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Bacillus subtilis SPB1 biosurfactant: Production optimization and insecticidal activity against the carob moth Ectomyelois ceratoniae
Abstract
Bacillus subtilis SPB1 was shown to produce a lipopeptide biosurfactant. The insecticidal activity of this
biosurfactant was evaluated against Ectomyelois ceratoniae Zeller, a moth pest of stored dates in Tunisia.
The LC50 and LC90 values after six days of contact were 152 mg/g and 641 mg/g, respectively. To promote an
economical production of this highly effective bioinsecticide, statistical experimental designs and
response surface methodology were employed to optimize the concentrations of agro-industrial residues
and humidity, for lipopeptide biosurfactant production by B. subtilis SPB1 under solid state fermentation.
The optimal medium leading to a production yield near to 28 mg of crude lipopeptide preparation per g
of wet solid material was composed of a mixture of 4.34 g of tuna fish flour and 5.66 g of potato waste
flour with a moisture content of 76%.
... Having the ability to decrease the surface tension, possessing emulsifying and oil-dispersing activities along with their efficiency under extreme conditions of salinity, pH and temperature, microbial surfactants have become very popular Markande et al. 2021;Debnath et al. 2022;Gayathiri et al. 2022;Sharma et al. 2022). They have become the best replacement for synthetic surfactants in various areas including medical and therapeutic fields Markande et al. 2021), cosmetic (Bouassida et al. 2017;Gayathiri et al. 2022), chemical industry like detergent formulation (Bouassida et al. 2018a;Mnif et al. 2023), food technology (Mnif et al. 2013a;Ribeiro et al. 2020;Debnath et al. 2022;Gayathiri et al. 2022), agriculture (Gayathiri et al. 2022) and for the biocontrol of plant pests (Mnif et al. 2013b;Markande et al. 2021). Moreover, they are widely used in environment and bioremediation as surface tension reducers, microbial growth inducers and flocculating agents, to improve hydrocarbon solubilization, mobilization and biodegradation, to increase dye biodecolorization and biodegradation and to remove HMs (Mnif et al. 2013c(Mnif et al. , 2013d(Mnif et al. , 2014(Mnif et al. , 2016(Mnif et al. , 2017a(Mnif et al. , 2017bBusi & Rajkumari 2016;Bouassida et al. 2018b;Markande et al. 2021;Sharma et al. 2022). ...
... In particular, being biodegradable and non-toxic, research on BioS is stimulated by major ecological concerns as they appear as the best choice to better fight against pollution. Being derived from microbial cells, BioS have great possibilities to be produced from renewable substrates with easy purification procedures (Mnif et al. 2013b(Mnif et al. , 2013d(Mnif et al. , 2021a(Mnif et al. , 2021b(Mnif et al. , 2021cZouari et al. 2014;Mnif et al. 2021aMnif et al. , 2021bGayathiri et al. 2022). Thus, having an anionic character, they have great opportunities to be exploited for metal sequestration enabling consequently metal desorption from soil particles and elimination from contaminated water Mnif et al. 2021a). ...
... Thus, given the incontestable concern of these molecules, their higher biodegradability (Darlane et al. 2016), biological and ecological compatibility (Gayathiri et al. 2022;Mnif et al. 2023), lack of toxicity (Camacho-Chab et al. 2013;Fei et al. 2020) and superior effectiveness against higher temperature, pH and salinity (Mnif et al. 2021a(Mnif et al. , 2021b(Mnif et al. , 2021c, BioS are very advantageous toward chemical surfactants. Moreover, they have the property to be generated from renewable and cheap substrates offering a low cost of production (Mnif et al. 2013b(Mnif et al. , 2013d(Mnif et al. , 2021a(Mnif et al. , 2021c Mnif et al. 2021c). In addition, we report the increase and decrease of the production yield and cost, respectively, by the innovation of novel fermentation systems including the submerged and solid state ones (Mnif et al. 2013b(Mnif et al. , 2013d(Mnif et al. , 2021a(Mnif et al. , 2021cZouari et al. 2014;Carolin et al. 2021). ...
Heavy metal pollution damages the ecosystems and presents a major problem for public health. Thus, an urgent need was developed to decrease the high levels of heavy metals in the soil and aquatic environments. With this aim, numerous physicochemical strategies were developed. However, they are money-consuming, require the use of energy and chemical additives and can release secondary compounds that can pollute and cause great damage to the environment. Then, biological methods based on the investigation of bacteria, fungi and plants along with their derived secondary active metabolites became the best alternatives. Using plant capacities, different phytoremediation strategies were developed such as phytoextraction, phytovolatilization, rhizofiltration and phytostabilization. Regarding bioremediation, bacterial biosorption of heavy metals, biolixiviation and lagooning offer great potential for their environmental cleaning. Additionally, the use of secondary active metabolites, such as biosurfactants, is well-studied. Generally, they are a class of structurally very varied molecules commonly synthesized by many microorganisms with amphiphilic character. Owing to their anionic charge, they have the capacity to sequestrate heavy metals permitting their elimination. Glycolipids and lipopeptides are among the most recognized biosurfactants with interesting heavy metal chelating properties.
... Additionally, this strategy permits to reduce the cost of wastes discharge and treatment (Almeida et al., 2017). In this regard, various studies reporting the use of complex agro-industrial wastes for lipopeptides production as substitutes of synthetic medium ingredients have been published in Submerged Fermentation (SmF) (Barros et al., 2008;Cho et al., 2009;Joshi et al., 2008;Zouari et al., 2015a) as well as in Solid State Fermentation (SSF) (Das and Mukherjee, 2007;Kim et al., 2009;Kuo, 2006;Mnif et al., 2013;Wang et al., 2008;Zouari et al., 2015b). They permit a high cost reduction along with valorization of agro-wastes. ...
... This procedure was considered as an important tool that could be used, on the one hand, to improve the production yield by optimizing the culture media compounds and conditions. On the other hand, a few experimental tests can be used to identify the ideal environmental conditions (Mnif et al., 2013). This technique worked well to improve BioS production by B. subtilis . ...
... Any overflow or overload in one of these values could influence the final yield . This production rate was similar to that obtained with the same strain (28 mg/g) by using 5.66 g of potato waste flour and 4.34 g of tuna fish flour by means of a moisture tenor of 76% (Mnif et al., 2013). Moreover, it was close to the highest yield ever recorded for B. subtilis SPB1 in SSF using, a combination of 6 g of olive leaf residue flour and 4 g of olive cake flour inoculated by an initial OD 600 of 0.08 with a total weight of the solid substrate of 10 g and 90% moisture content (Zouari et al., 2015b). ...
Bacillus subtilis SPB1 derived biosurfactants (BioS) proved its bio-control activity against Agrobacterium tumefaciens using tomato plant. Almost 83% of disease symptoms triggered by Agrobacterium tumefaciens were reduced. Aiming potential application, we studied lipopeptide cost-effective production in both fermentations systems, namely the submerged fermentation (SmF) and the solid-state fermentation (SSF) as well as the use of Aleppo pine waste and confectionery effluent as cheap substrates. Optimization studies using Box–Behnken (BB) design followed by the analysis with response surface methodology were applied. When using an effluent/sea water ratio of 1, Aleppo pine waste of 14.08 g/L and an inoculum size of 0.2, a best production yield of 17.16 ± 0.91 mg/g was obtained for the SmF. While for the SSF, the best production yield of 27.59 ± 1.63 mg/g was achieved when the value of Aleppo pine waste, moisture, and inoculum size were, respectively, equal to 25 g, 75%, and 0.2. Hence, this work demonstrated the superiority of SSF over SmF.
... In this aim, to enhance lipopeptide production by B. subtilis ZNI5, we adopted a strategy based on the use of an agricultural byproduct along with the optimization of fermentation parameters. As previously adopted, we opt for the use of experimental planning methodology to improve BioS production [6,57,60,61]. Moreover, Taguchi design was applied as an efficient tool to enhance the most biotechnological process [61,68,102,104]. ...
... As previously adopted, we opt for the use of experimental planning methodology to improve BioS production [6,57,60,61]. Moreover, Taguchi design was applied as an efficient tool to enhance the most biotechnological process [61,68,102,104]. It is a fractional factorial design that can show process variability and stability [61,68]. ...
... Moreover, Taguchi design was applied as an efficient tool to enhance the most biotechnological process [61,68,102,104]. It is a fractional factorial design that can show process variability and stability [61,68]. It permits to study simultaneously the effects of many parameters on process mean and variance [61,68]. ...
The present study summarizes the valorization of date flour by the production of lipopeptide biosurfactant (BioS) by Bacillus subtilis ZNI5 (MW091416). A Taguchi design permitted the formulation of a medium composed only of 6% date flour and 0.5% yeast extract within 2 days of incubation at 150 rpm with a maximal surface tension (ST) reduction of about 27.8 mN/m. The characterization of the lipopeptide shows a CMC value of about 400 mg/L with a minimal ST of 30 mN/m and an ability to disperse oil to about 80 mm at 800 mg/L. Having reduced phytotoxicity, the ZNI5 BioS and ZNI5 strain were assayed for Copper and Cobalt chelation and biosorption. The improvement of the germination index of radish seeds irrigated by the treated contaminated water showed the great potential application of ZNI5 lipopeptide in the bioremediation of heavy metals.
... As portrayed in our previous studies, B. subtilis SPB1 generated a mixture of lipopeptides biosurfactant belonging to surfactin, iturin and fengycin isoforms as identified by LC-MS analysis [26]. The SPB1 biosurfactants exhibit a broad spectrum of actions, including antimicrobial activity against microorganisms with multidrug resistant profiles [27], antifungal activity toward phytopathogenic fungi [28], insecticidal activity [29][30][31], antioxidant activity [32] and antidiabetic as well as antilipidemic properties in alloxaninduced diabetic rats [33][34][35] with a reduced toxicity toward living cells [36]. This is indicative of their potential application in biomedical, pharmaceutical and agricultures fields. ...
... desiccated at 105 °C until constant weight and evaluated by gravimetric method [31]. ...
Biosurfactants stand for highly useful and promising compounds. They basically serve for a variety of applications in multiple industries and aspects of human life. Therefore, it is highly required to improve their production yield especially through the development of new and more efficient fermentation processes. In this aim, batch and fed-batch were studied and compared in terms of their effective biosurfactant production by Bacillus subtilis SPB1. Experiments of fed-batch fermentations were carried out through three different glucose feeding strategies, namely the pulsed, the constant Donespeed and the exponential feeding. The comparison between different fermentation processes revealed that fed-batch process proved to be a more efficient cultivation strategy than the batch process in terms of cell biomass, biosurfactant production and productivity. Among the three different feeding strategies, the exponential feeding process achieved the highest fermentation results of final biosurfactant concentration. The latter increased more than twofolds compared to batch fermentation.
... The insecticidal activity of lipopeptid biosurfactant of B. subtilis SPB1against Ectomyelois ceratoniae (Zeller) (Lep.: Pyralidae), was investigated by Mnif, Elleuch, Chaabouni, & Ghribi (2013). The LC 50 and LC 90 values after six days of contact were measured as 152.3 and 641 μg/g, respectively. ...
... Studies on the histopatological effects of B. subtilis biosurfactants on the insect midgut cells revealed the lethal changes at the cellular level. Vesicale formation in the apical of cells, lysis vacuolization of columnar cells and destruction of epithelial cell and their boundaries in the midgut larvae of E. ceratoniae (Mnif et al, 2013) and S. littoralis (Ghribi et al, 2012a) were represented. Also, according to Ghribi, Elleuch, Abdelkefi-Mesrati, Boukadi, & Ellouze-Chaabouni (2012b), the tested dose level of B. subtilis SPB1 caused strong histopathological disturbances in the midgut of Ephestia kuehniella Zeller (Lep: Pyralidae). ...
The effects of Bacillus subtilis, wild type bacterium UTB1 and mutant M419, on two larval instar groups of the diamondback moth, Plutella xylostella L. (Lep.: Plutellidae) until three days after treatment have been investigated. Larval mortality rate increased with increasing the concentration and over the days after treatment. Increasing the larval instar resulted in elevating the LC50 value for both types of biosurfactants. In terms of lethality, there was no significant difference between the two bacteria in the final mortality rate after three days.
... They have received much attention in pest management and have been considered as green pesticides for many years, microbial bioinsecticides have controlled agricultural pests. The Bacillus sp has been found to produce lipopeptides including surfactin, iturin, bacilliomycin, fengycin, and lichenysin (Mnif, Elluech, Chaabouni, & Ghribi, 2013;Mukherjee & Das, 2005). These surfactants are found to have potent larvicidal activity (Chung et al., 2008;Geetha, Manonmani, & Prabakaran, 2011). ...
... The B. subtilis producing cyclic lipopeptides and lipopeptides are found to have larvicidal effect on insects like mosquitoes and Spodotera littoralis (Geetha et al., 2011;Geetha, Prabakaran, Paily, Manonmani, & Balaraman, 2007), B. thuringiensis are found to have larvicidal effect on insects like Colorado potato beetle and Spodoptera litoralis (Ochoa-Campuzano, Real, Matinez-Ramirez, Bravo, & Rausell, 2007;Ben-Farhat-Touzri et al., 2013). Bacillus subtilis SPB1 biosurfactant has been found to produce lipopolypeptide surfactants which have insecticidal activity against storage insects, carob moths, E. Ceratoniae (Mnif et al., 2013). This shows that Bacillus sp cause death of treated insects by targeting the midgut tissue via the vesicle formation in the apical region of cells and lysis and strong vacuolization of columnar cells. ...
Beverage or “drinks” inclusively stands for various consumable liquids, such as soft drinks, juices, milk derivatives, alcohols, beers, and hot liquids such as coffee, tea, hot chocolate, caffeinated drinks, etc. In contemporary times, various other types of beverages are produced for purposes such as immunization, personal care, and social celebrations, etc., with the main aim of compensation of thirst and balancing electrolytic equilibrium in the body system. With the evolution of health science, more consciousness regarding health and wellness has spread among people, and modification of traditional beverages is now a demand. Consumers around the globe are looking for drinks that are more sophisticated, more natural, and authentic. The definition of new generation food invokes more “green” and less synthetic foods for consumption, which includes lowering of addition of sugars, synthetic flavors, and chemicals. The demand for add-on benefits such as promotion of immunity, fitness, and overall wellness without altering taste is on top. To fulfill all these demands, the formulation of beverages needs a holistic understanding of science and technology of production and also alternative biomolecules that may replace the synthetic chemicals used in beverages. In this context, the most potential candidate in modern science has recognized is biosurfactants (BSs). BSs are termed as “new generation bio-chemicals,” because of their excellent properties, which include the least toxicity, effective environmental compatibility, efficient biodegradability, enhanced foaming property, advanced selectivity, specificity at exciting temperature, pH, and salinity; also, for their facility to be produced from renewable feedstock. In this book chapter, we have extensively discussed the application of both microbial-assisted BSs and plant-based BSs, in the production of various types of beverages. BSs act as emulsifiers, antioxidants, antimicrobials, and antiadhesives. Each application is discussed with scientific documentation and examples. The real-time commercial applications and their add-on benefits to promote human health have also been discussed in this book chapter. The recent market reports along with prospects of these BSs in the beverage industry have also been reported for the benefit of readers.
... They have received much attention in pest management and have been considered as green pesticides for many years, microbial bioinsecticides have controlled agricultural pests. The Bacillus sp has been found to produce lipopeptides including surfactin, iturin, bacilliomycin, fengycin, and lichenysin (Mnif, Elluech, Chaabouni, & Ghribi, 2013;Mukherjee & Das, 2005). These surfactants are found to have potent larvicidal activity (Chung et al., 2008;Geetha, Manonmani, & Prabakaran, 2011). ...
... The B. subtilis producing cyclic lipopeptides and lipopeptides are found to have larvicidal effect on insects like mosquitoes and Spodotera littoralis (Geetha et al., 2011;Geetha, Prabakaran, Paily, Manonmani, & Balaraman, 2007), B. thuringiensis are found to have larvicidal effect on insects like Colorado potato beetle and Spodoptera litoralis (Ochoa-Campuzano, Real, Matinez-Ramirez, Bravo, & Rausell, 2007;Ben-Farhat-Touzri et al., 2013). Bacillus subtilis SPB1 biosurfactant has been found to produce lipopolypeptide surfactants which have insecticidal activity against storage insects, carob moths, E. Ceratoniae (Mnif et al., 2013). This shows that Bacillus sp cause death of treated insects by targeting the midgut tissue via the vesicle formation in the apical region of cells and lysis and strong vacuolization of columnar cells. ...
Biosurfactants may be defined as molecules of amphiphilic nature having the capacity of decreasing both surface as well as interface tension between nonmiscible fluids. These are generally classified on the basis of their microbial origin and chemical composition. These are environment friendly molecules with lesser toxic effect and having higher biodegradation. These have full potential of replacing the chemical surfactants. The most important biosurfactants include Glycolipids and lipopeptides. Some other classes of biosurfactants are Phospholipids, fatty acids and Polymeric. These biosurfactants are manufactured throughout the microbial growth on both water soluble or insoluble substrates. These have widespread usage in bioremediation, pathogens management, medicines, cosmetics, and petroleum industry. Although, their usage is encouraging in bioremediation practices, their mass production on industrial basis is a tough task because of costly inputs low manufacturing outputs.
... They have received much attention in pest management and have been considered as green pesticides for many years, microbial bioinsecticides have controlled agricultural pests. The Bacillus sp has been found to produce lipopeptides including surfactin, iturin, bacilliomycin, fengycin, and lichenysin (Mnif, Elluech, Chaabouni, & Ghribi, 2013;Mukherjee & Das, 2005). These surfactants are found to have potent larvicidal activity (Chung et al., 2008;Geetha, Manonmani, & Prabakaran, 2011). ...
... The B. subtilis producing cyclic lipopeptides and lipopeptides are found to have larvicidal effect on insects like mosquitoes and Spodotera littoralis (Geetha et al., 2011;Geetha, Prabakaran, Paily, Manonmani, & Balaraman, 2007), B. thuringiensis are found to have larvicidal effect on insects like Colorado potato beetle and Spodoptera litoralis (Ochoa-Campuzano, Real, Matinez-Ramirez, Bravo, & Rausell, 2007;Ben-Farhat-Touzri et al., 2013). Bacillus subtilis SPB1 biosurfactant has been found to produce lipopolypeptide surfactants which have insecticidal activity against storage insects, carob moths, E. Ceratoniae (Mnif et al., 2013). This shows that Bacillus sp cause death of treated insects by targeting the midgut tissue via the vesicle formation in the apical region of cells and lysis and strong vacuolization of columnar cells. ...
The biosurfactants produced by the microbes are mostly glycolipid which
owing to their low toxicity, biodegradability shows a greater utility than
the chemical surfactants. With the enhanced use of biosurfactants the envi�ronment gets converted into a green environment. They apart from hav�ing these properties have the emulsifying capability, pore-forming ability and
antibiofilm forming abilities which have made them potent biopesticides.
Numerous reviews showed the efficiency of glycolipids. The antiphyto�pathogenic activities of glycolipids, the insecticidal and larvicidal activities
their antiadhesive properties have attracted the industries in producing
amplified amounts of these green compounds
... Additionally, economical production is of great interest for the decrease the cost of production and the maximization of the production yield. Several food industry wastes were used in the production of surfactant lipopeptides such as millet flour [24], sesame peel flour [44], rice bran [80], tuna fish flour and potato waste flour [46], soybean flour [36,88], soybean sauce [15], potato residues [88], brewery waste [57], papaya waste [83], molasses and whey [26,32,76] and butter milk and poultry-transforming wastes Zouari et al. [95]. These raw materials are very rich in sugars corresponding to carbon substrates favorable for the production of lipopeptides. ...
... The model coefficients were estimated using multi-linear regression by the statistical software package (Nemrod-W by LPRAI Marseilles, France) as described in our previous works [24,[45][46][47]. The multiple regression analysis permitted to evaluate the statistical significance of the model based upon the F test with unequal variance (p < 0.05). ...
Lipopeptides biosurfactants (BioS) are natural surface-active compounds produced by a variety of microorganisms. They have great interest in environmental, biomedical and agro-industrial fields. However their large-scale application and production is limited by the cost of culture media and the low yield of production. Therefore, the improvement of the production yields and the development of efficient and cost-effective bioprocess became of a great interest. In this aim, we applied the response surface method to optimize an economic BioS production by a newly isolated strain Bacillus mojavensis BI2 on date Juice called “Luegmi” as unique carbon and nitrogen source. Using a Box-Bhenken design, we studied the effect of three independent variables on lipopeptide production; Leugmi concentration, Na2HPO4 and incubation time. The results of this study showed that Leugmi concentration at 25%, Na2HPO4 at 0.1% and incubation time of 24 h were optimal conditions for BioS production, with a maximum Surface Tension (ST) decreasing capacity of 55% corresponding to 27 mN/m and an Oil Dispersing Activity (ODA) of 30 cm2 corresponding to a diameter of 6 cm. Preliminary characterization of the BioS produced on Luegmi by UV-Spectra and Thin Layer Chromatography showed its lipopeptide nature. Physic-chemical characterization of the produced lipopeptide on Leugmi showed its great surface activities and stabilities at different pH, temperature and salts concentration. The results of this study suggested that Leugmi, an agricultural byproducts can be used as a low-cost substrate to enhance the yield of lipopeptide BioS with great surface activities for potential environmental application.
... Ecology, population, damage rate, host preference and management of carob moth have been extensively studied in Turkey and globally (Mehrnejad 1993;Mamay et al., 2014b;Mamay and Unlu, 2013;Sobhani et al., 2015;Mamay and Bilgili, 2020). Numerous control methods, including mating disruption Dhoubi et al., 2017), mass trapping (Mamay and Dag, 2016;Zougari et al., 2020), biological control (Memari et al., 2016;Zougari et al., 2020), sterile insect technique (Chakroun et al., 2017;Soufbaf et al., 2018) (Sheikhali et al., 2009;Karami et al., 2011;Mamay, 2018) and chemical control (Warner et al., 1990;Peyrovi et al., 2011;Mnif et al., 2013) have been explored to reduce carob moth damage in pomegranate orchards. ...
... Chemical control of carob moth has been recommended by several researchers (Warner et al., 1990;Peyrovi et al., 2011;Mnif et al., 2013). However, despite 4-5 conventional pesticides available, carob moth often remains a challenging pest in pomegranate orchards of Turkey. ...
Carob moth [Ectomyelois ceratoniae Zeller (Lepidoptera: Pyralidae)] is a serious pest of pomegranate orchards in several parts of the world, including Turkey. Insecticides are often not a viable option to manage this pest as the larvae are protected inside the pomegranate fruit. This study evaluated the potential of fruit bagging (B), calyx removal (RC) and fruit bagging after calyx removal (BRC) for managing carob moth during 2016 to 2018 in two districts of Şanlıurfa Province, Turkey. Fifty trees were randomly selected from each location when pomegranate fruits reached the size of a walnut, i.e., approximately 3-5 cm diameter (end of May to start of June). Two fruits were marked for each method on each selected tree, whereas two fruits were reserved for control treatment. All fruits were examined during mid-August and late-September to determine carob moth infestation. The tested methods significantly (p<0.01) differed for carob moth damage at both locations during each year. All the methods successfully controlled carob moth compared to control treatment. Infestation rate was 0%, 3.75% 23.75% and 57.25% for BRC, B, RC and control treatments, respectively. Covering pomegranate fruits with net bags has potential as an environment-friendly alternative management method for carob moth. Fruit bagging after calyx removal can give 100% control of the pest without any damage to the fruit. Nonetheless, future studies are needed to explore whether bagging can protect fruits from abiotic stresses and other pests.
... Additionally, economical production is of great interest for the decrease the cost of production and the maximization of the production yield. Several food industry wastes were used in the production of surfactant lipopeptides such as millet our (Ghribi et al. 2012), sesame peel our (Mnif et al. 2013a), rice bran (Shih et al. 2008), tuna sh our and potato waste our (Mnif et al. 2013c), soybean our (Wang et al. 2008; ), soybean sauce (Cho et al. 2009), potato residues (Wang et al. 2008, brewery waste (Moshtagh et al. 2019), papaya waste (Soares et al. 2018), molasses and whey (Rodrigues et al. 2006); (Joshi et al. 2008); (Hippolyte et al. 2018) and butter milk and poultry-transforming wastes (Zouari et al. 2019a). These raw materials are very rich in sugars corresponding to carbon substrates favorable for the production of lipopeptides. ...
... They are used to study the effects of the variation of the factors in the domain studied and, consequently, to determine the optimal experimental conditions. In fact, the elliptical nature of the contour plots indicated the signi cance of the interactions between the corresponding variables (Mnif et al. 2013d(Mnif et al. , 2013c(Mnif et al. , 2013b(Mnif et al. , 2013a. As mentioned previously, the enhancement of incubation time had no signi cant effect on biosurfactant production. ...
Lipopeptides Biosurfactants are natural surface-active compounds produced by a variety of microorganisms. They have great interest in environmental, biomedical and agro-industrial fields. However, the high cost of culture media and the low yield of production limit their large-scale production and application. The development of efficient and cost-effective bioprocess became of a great interest for the improvement of the yield of biosurfactants and the decrease of production cost. In this aim, we applied the response surface method to optimize an economic biosurfactant production by a newly isolated strain B. mojavensis BI2 on date syrup called “Luegmi” as unique carbon and nitrogen source. Using a Box-Bhenken design, we studied the effect of three independent variables on lipopeptide production; Leugmi concentration, Na 2 HPO 4 and incubation time. The results of this study showed that Leugmi concentration at 25%, Na 2 HPO 4 at 0.1% and incubation time of 24 hours were optimal conditions for biosurfactant production, with a maximum surface tension decreasing capacity of 55% corresponding to 27 mN/m and oil dispersing of 30 cm 2 corresponding to a diameter of 6 cm. Preliminary characterization of the biosurfactant produced on Luegmi by UV-Spectra and Thin Layer Chromatography showed its lipopeptide characters. Physic-chemical characterization of the produced lipopepetide on Leugmi showed its great surface activities and stabilities at different pH, temperature and salts concentration. The results of this study suggested that Leugmi, an agricultural byproducts can be used as a low-cost substrate to enhance the yield of lipopeptide biosurfactants with great surface activities for potential environmental application.
... The six-day contact LC50 and LC90 were 152 mg/g and 641 mg/g, respectively. Thus, results showed that E. ceratoniae is a primary site of action of the biosurfactant SPB1 and tissue disintegration leads to larval death [73]. In fact, the potential use of the biosurfactant B. subtilis SPB1 formulated as a biological control agent can successfully control E. ceratoniae within shelflife (in vivo) and protect the crop. ...
... A lipopeptide biosurfactant produced by B. subtilis SPB1 has been shown to be highly effective against E. ceratoniae infesting dates stored in Tunisia, causing histopathological destruction of larval tissues. Consequently, this biosurfactant with such properties can be exploited for the formulation of a new microbial biopesticide for the effective control of E. ceratoniae larvae [73] and as a promising alternative to the use of chemical fumigants as the main control tool. In addition, it is interesting to note that applications of B. thuringiensis (Berliner) as a biopesticide have been shown to be harmless to the parasitoid Trichogramma cacoeciae Marchal, Trichogramma bourarachae Pintureau and Babault and Trichogramma evanescens Westwood in pomegranate plantations in Tunisia, implying that the combined application of Bt with release of either parasitoid species would be a promising control approach against E. ceratoniae [59]. ...
Ectomyelois ceratoniae integrated pest management defines three main keys: Sterile Insect Technique (SIT), post-harvest chemical control and biological control. Each component is described with information on its implementation, adoption and importance in palm groves. The SIT, a control tool using gamma radiation to sterilize male and/or female moths before release, has been shown to significantly reduce density in subsequent generations. Alternatively, date fumigation with CO 2 , ethyl formate or eucalyptus essential oils has proven to be a promising control alternative to fumigation with methyl bromide. However, biological control can be considered as the most environmentally friendly and better option against this pest. A lipopeptide biosurfactant produced by Bacillus subtilis SPB1 has been shown to be very effective against E. ceratoniae infesting stored dates. In addition, the combined application of Bacillus thuringiensis with the release of para-sitoids of the genus Trichogramma, Phanerotoma or Bracon would be a promising control approach.
... Several reports indicated that Bacillus subtilis have insecticidal activity against some lepidopteran pests Larvae including Ephestia kuehniella (Lep: Pyralidae) [5], Ectomyelois ceratoniae (Lep: Pyralidae) [15] and Spodoptera littoralis (Lep: Noctuidae) [16,5]. ...
... Ghribi et al. [5] reported B. subtilis SPB1 causes mortality of Ephestia kuehniella in larval stage. Studies of Mnif et al. [15] have shown biosurfactant of B. subtilis SPB1 capable of causing mortality of carob moth, Ectomyelois ceratoniae larvae. Geetha et al. [33], Geetha et al. [34], Geetha and manonmani [35], have reported that a strain of B. subtilis exhibiting mosquito larvicidal, pupicidal and adulticidal activity. ...
Bacillus subtilis inhibits growth of plant pathogen and causes mortality of plant pests by producing lipopeptide biosurfactans. In this study secondary metabolites produced by Bacillus subtilis mutant M419 was extracted and production of lipopeptide surfactants of the mutant was observed by hemolytic activity and oil spreading techniques. The effects of the biosurfactant on mortality of the first and second instars of Papilio demoleus Linnaeus was evaluated by leaves immersion method at 3600, 1800, 900, 450 and 0 mg/l concentrations in laboratory. The LC50 and LC90 values after 4 days of contact were measured 1172.145 mg/l and 3336.999 mg/l, respectively. Results indicated that, these values were 3.8-fold and 1.62-fold lower than that obtained after 2 and 3 days, respectively. The crude biosurfactant retained the larvicidal activity even when autoclaved at 121 °C for 15 min. B. subtilis M419 was able to inhibit considerably Aspergillus flavus growth in a dual culture assay.
... Bacillus thuringiensis shows promise as a larvicide against E. ceratoniae, and the combination of a low level of B. thuringiensis with Beauveria bassiana produces a greater reduction in larvae than a low level of B. thuringiensis. In addition, Bacillus subtilis is shown to be highly effective against E. ceratoniae infesting dates stored in Tunisia (Mnif et al., 2013). Note that the applications of B. thuringiensis (Berliner) as a biopesticide had no effect on parasitoid natural enemies such as Trichogramma sp. ...
This datasheet on Ectomyelois ceratoniae covers Identity, Overview, Distribution, Dispersal, Hosts/Species Affected, Diagnosis, Biology & Ecology, Environmental Requirements, Natural Enemies, Impacts, Prevention/Control, Further Information.
... Waste product use improves cost-efficiency; for example, potato peel and fish wastes enable the production of active lipopeptides with MICs for Mucor sp. at 6.25 ppm and Aspergillus niger at 12.5 ppm [171]. An extended culture time enhances yield [18] and the product's potential to thwart pathogenic bacteria and fungi upon application [172]. ...
Biological control is an important process for sustainable plant production, and this trait is found in many plant-associated microbes. This study reviews microbes that could be formulated into pesticides active against various microbial plant pathogens as well as damaging insects or nematodes. The focus is on the beneficial microbes that colonize the rhizosphere where, through various mechanisms, they promote healthy plant growth. Although these microbes have adapted to cohabit root tissues without causing disease, they are pathogenic to plant pathogens, including microbes, insects, and nematodes. The cocktail of metabolites released from the beneficial strains inhibits the growth of certain bacterial and fungal plant pathogens and participates in insect and nematode toxicity. There is a reinforcement of plant health through the systemic induction of defenses against pathogen attack and abiotic stress in the plant; metabolites in the beneficial microbial cocktail function in triggering the plant defenses. The review discusses a wide range of metabolites involved in plant protection through biocontrol in the rhizosphere. The focus is on the beneficial firmicutes and pseudomonads, because of the extensive studies with these isolates. The review evaluates how culture conditions can be optimized to provide formulations containing the preformed active metabolites for rapid control, with or without viable microbial cells as plant inocula, to boost plant productivity in field situations.
... Biosurfactants are amphiphilic molecules mainly produced by microorganisms as a secondary metabolite. They possess both hydrophilic and hydrophobic moieties and are able to display a variety of surface activities and help to solubilize hydrophobic substrates (Mnif et al., 2013). The biosurfactants are used in cosmetic, pharmaceutical, chemical, food, agriculture, cleansers, enhanced oil recovery industries, and in bioremediation of oil contaminated sites, considering the advantages and characteristics as thermostability, tolerance to ionic strength, biodegradability and low toxicity (Jain et al., 2013a andb) Biosurfactants exhibit such important advantages but they have not been yet employed extensively in industry because of relatively high production cost. ...
In this present study, biosurfactant producing microorganism seudomonasa eruginosa, was isolated. The bio surfactant production was studied using a Minimal Salt Medium with crude oil (1 %) as the hydrocarbon. The optimization study was carried out using various carbon, nitrogen sources, pH, temperature, hydrocarbons, and trace elements. The effect of dry cell biomass, biosurfactant production, emulsification activity and surface tension were studied. The glycerol and sodium nitrate was the best carbon and nitrogen source studied with the isolate. The environmental factors such as pH 7 and temperature 30oC were found to be optimum for the biosurfactant production. Among the hydrocarbon tested the crude oil and n-hexadecane showed statistically on par results.
... The variance and mean larval mortality calculated using the SAS software is shown in Tables 3 and 4, respectively. A comparison between the effects of the biosurfactant on larval mortality demonstrated that the concentration of 10000 µg/g on a ninth day had the highest mortality (63.33%) on the larvae and the LD50 equal to 25001.7 µg/g was calculated for S. epidermidis on a ninth day by the Probit They can also modify membrane permeability by channel formation or membrane solubilization through their insertion into lipid bilayers due to hydrophobic interactions [35]. ...
Biosurfactants, produced by microorganisms, are surface-active compounds with abundant applications in miscellaneous industries like food, cosmetics, bioremediation, agriculture, and so on. The primary objective of this study was to investigate the larvicidal activity of biosurfactants produced by Staphylococcus epidermidis (S. epidermidis) isolated from petrochemical wastes. As the secondary objective, this study was to perform a phylogenetic analysis of this bacterium. To this end, the type of the extracted biosurfactant was characterized using the thin-layer chromatography (TLC) and the gas chromatography/mass spectrometry (GC-MS). The isolated bacterium was then identified through molecular tests based on 16S ribosomal ribonucleic acid (16S rRNA) and serum response factor (srf) genes. Likewise, the phylogenetic tree of the bacterium was deduced via the Molecular Evolutionary Genetics Analysis (MEGA-X) software. Besides, the larvicidal activity of the biosurfactant on the larvae of flour beetles, Tribolium castaneum (T. castaneum), was examined. The mean mortality rate and the lethal dose (LD50) were further calculated using the Statistical Analysis System (SAS) and the Probit Analysis-MSChart software. Totally, nine diverse types of colonies were isolated and three of them were found with potential activity to produce biosurfactants. The best bacterium was accordingly selected for subsequent experiments recruiting the oil displacement process and the emulsification index (E24). The extracted biosurfactant was then characterized as a lipopeptide. Moreover, biochemical tests showed that the bacterium was Gram-positive cocci of gamma species. Hemolysis and molecular tests also confirmed that the bacterium was S. epidermidis. As well, the presence of the SRF gene in the isolation was established via the polymerase chain reaction (PCR). The mean mortality rate revealed that the mentioned bacterial biosurfactant at the concentration of 10000 µg/g and on the ninth day of the treatment had the highest larval mortality rate (63.33%). In addition, the LD50 equal to 25001.7 μg/g was calculated for S. epidermidis on the ninth day. The results demonstrated that the biosurfactant produced by this bacterium was endowed with an acceptable ability to control T. castaneum and it could be used in further research on the larvae of other insects.
... (Ghribi et al., 2012) . (Mnif et al., 2013) . ...
Biosurfactants are surface active biomolecules that are produced by microorganisms and have diffetent applications. In recent years, these biological molecules have received much attention due to their special properties such as specificity, low toxicity and easy preparation. The effect of biosurfactant produced by Staphylococcus hominis on red flour beetle larvae (Tribolium castaneum) was investigated. This experiment was done with three replications by different concentrations, and the results were analysed by SAS software. The results of the mean mortality percentage showed that the mentioned bacterial biosurfactant at a concentration of 10000 µg/g on the ninth day of treatment with 66.67% had the highest effect on larval mortality. LD50 was evaluated as 6395758/49, 1131823.60 and 15359.4 µg/g on the fifth, seventh and ninth days, respectively. The results showed that the biosurfactant produced by S. hominis had an acceptable ability to control T. castaneum.
... Numerous studies have also evaluated the effectiveness of biological control agents, such as Bt in controlling CM. For example, the biosurfactant of Bacillus subtilis (Ehrenberg) Cohn was found to be effective for CM control (Mnif et al. 2013), and laboratory bioassay demonstrated the high susceptibility of fourth instar CM larvae to Bt (Harpaz and Wysoki 1984;Elsayed and Bazaid 2011). Further, Ksentini et al. (2010a) reported harmlessness of Bt application to three Trichogramma species collected from CM on pomegranates in Tunisia, advocating its application along with these egg parasitoids. ...
Balanites fruit pulp and seed kernel contain considerable amount of steroidal saponins, which are used as raw material for the production of pharmaceutical drugs. However, insect and avian pests are the key limiting factors in balanites production. This study was conducted to record the causal insect and avian pests and level of their infestation. Balanites fruits fallen on the ground were collected at regular intervals for two fruiting seasons at Keren, Eritrea. The fruits were put in polybags and stored at room temperature. The emerging insects were counted and percent infestation was calculated. The insects identified were balanites stone borer, Eublemma (= Eupsoropsis) robertsi (Lepidoptera: Erebidae) and carob moth, Apomyelois (=Ectomyelois) ceratoniae (Lepidoptera: Pyralidae). Eublemma robertsi larva consumed the kernel and bored into the stone with one exit hole (ca. 3 mm) at pre-pupal stage whereas A. ceratoniae larvae infested and contaminated fruit pulp with faecal waste. More than 70% of fruits collected during October and November were infested by E. robertsi and oviposition of 1-3 eggs were found on 73% of examined fruits. Damage from A. ceratoniae was unnoticeable in field-collected fruits but larval infestation was observable after one month of storage. The speckled mousebird, Colius striatus (Coliiformes: Coliidae), was the most frequent avian visitor, which not only nibbled on fruits attached to branches but also caused drop of fruits to the ground. Fruit damage caused by birds ranged 58 to 95% during the two fruiting seasons.
... The date moth [Apomyelois (Ectomyelois) ceratoniae, Zeller] is a cosmopolite pest of the many fruits, nuts and dried fruits during storage (Gothilf, 1984;Warner, 1988). Therefore, numerous studies have been conducted in different parts of the world to determine the organisms that can be used in the control of this insect (Alrubeai, 1988;Elsayed and Bazaid, 2011;Mnif et al., 2013). Similarly, in the study, conducted by Lange in 1991 from Argentina, they declared the microsporidiosis from A. ceratoniae which were collected from walnuts. ...
In this study, a microsporidian pathogen of the date moth (Apomyelois (Ectomyelois) ceratoniae, Zeller, 1839) also known as the carob moth, is described based on light microscopy, ultrastructural characteristics and comparative molecular analysis. The pathogen infects the gut and hemolymph of A. ceratoniae. All development stages are in direct contact with the host cell cytoplasm. Fresh spores with nuclei arranged in a diplokaryon are oval and measured 3.29 ± 0.23 μm (4.18-3.03 μm, n = 200) in length and 1.91 ± 0.23 μm (2.98-1.66 μm, n = 200) in width. Spores stained with Giemsa's stain measured 3.11 ± 0.31 μm (3.72-2.41 μm, n = 150) in length and 1.76 ± 0.23 μm (2.16-1.25 μm, n = 150) in width. Spores have an isofilar polar filament with 10-12 coils. An 1110 bp long alignment of the current microsporidium showed an SSU rRNA gene difference of only 0.0009, corresponding to >99.91% sequence similarity with Nosema fumiferanae, while RPB1 gene sequences were 98.03% similar within an alignment of 969 bp. All morphological, ultrastructural and molecular features indicate that the microsporidian pathogen of A. ceratoniae is the new isolate of the N. fumiferanae and is named here as Nosema fumiferanae TY61.
... Biosurfactants are amphipathic molecules having both hydrophilic and hydrophobic moieties. Biosurfactants have the ability to reduce surface and interfacial tensions by accumulating at the interface between two immiscible fluid phases (1) . Biosurfactants are surfactants produced by microorganisms, mostly in microbial cell surfaces or excreted extracellularly (2) . ...
... Surfactants are amphipathic compounds which have both hydrophilic and hydrophobic portions which can decrease surface tension between two liquids or between liquid and solid (1) . Synthetic surfactant and biosurfactant are main two groups of surfactant. ...
... Surfactin showed excellent surface properties such as low critical micelle concentration (CMC) [16], stable emulsification properties [17] and wettability [18], and it also exhibited hemolytic [19], anticoagulant [20], antimicrobial [21] and antitumoral [22] activities. Due to its outstanding surface properties and special bioactivities, surfactin has attracted much attention from the communities of pharmaceuticals [23], bioremediation [24], microbial enhanced oil recovery [25] and many other fields. ...
A new member of the surfactin family of microbial lipopeptides has been isolated from the cell broth of Bacillus subtilis TD 7 by reverse phase high performance liquid chromatography (RP-HPLC), and identified by FT-IR, GC-MS, LC-MS/MS, ¹H-NMR and ¹³C-NMR. The surfactin-C11 consists of a heptapeptide with the sequence of N - Glu - Leu - Leu - Val - Asp - Leu - Leu - C, and a β-hydroxy fatty acid chain with 11 carbons, which is a new member with the shortest hydrophobic chain among the surfactin family produced by B. subtilis. The critical micelle concentration (CMC) of the surfactin-C11 is 5.59 × 10⁻⁵ mol/L in 10 mmol/L phosphate buffer solution (PBS, pH 7.4) at 25 °C, and the surface tension at CMC (γCMC) is 34.42 mN/m. The hemolytic activities of the surfactin-C11 on 2% defibrinated sheep blood showed a HC50 of 448.51 μmol/L. Surfactin with short fatty acid chain has low toxicity on erythrocyte, which implies potential applications in biotechnological and pharmaceutical fields.
... A lipopeptide biosurfactant produced by Bacillus subtilis SPB1 was shown to be highly effective against E. ceratoniae infesting stored dates in Tunisia, causing histopathological destruction in larvae tissues. Accordingly, this biosurfactant with such properties can be exploited for the formulation of a novel microbial biopesticide for effective control of E. ceratoniae larvae (Mnif et al. 2013) and as promising alternative to the use of chemical fumigants as main control tool. Moreover, interestingly, applications of Bacillus thuringiensis (Berliner) as biopesticide were shown to be harmless to the parasitoids Trichogramma cacoeciae Marchal, Trichogramma bourarachae Pintureau & Babault, and Trichogramma evanescens Westwood in pomegranate plantations in Tunisia, implying that combined application of Bt with release of either parasitoid species would be a promising control approach against E. ceratoniae (Ksentini et al. 2010a). ...
An overview on the bio-ecology, natural enemies and pest contol tools of the main pests infesting carob tree (Ceratonia siliqua L.), pods and seeds in the Mediterranean region is provided herein. Most of the species are occasionally present on host carobs where they did not cause serious damage. In particular, the occurrence of mealybugs, soft and armored scales and also mites is usually sporadic. This is also the case for dipteran and lepidopteran pests, except for the most damaging and economic species, the carob moth Ectomyelois ceratoniae (Zeller), a highly polyphagous insect that can infest carob either in open-field or in storage.
Cause of wounding are bark and wood-boring coleopteran insects, which can induce severe wilting and/or death of carob branches and trunk. The recent introduction in Europe of two species of Xylosandrus spp. (X. compactus and X. crassiusculus) is of increasing importance, due to their proven initial aggressiveness in Italy. Brief details regarding moth and rodent populations residing inside the storage buildings are also emphasized. Obviously, one aspect warranting special attention concerns the introduction and rapid spread in the Mediterranean region of invasive alien insect species such as some ambrosia beetles.
... The global biocontrol market of these BCAs was expected to rise to 3-4 billion US dollars by 2017 (Velivelli et al. 2014). However, Bacillus-derived lipopeptides have rarely been developed commercially as fungicides (Wei et al. 2010;Ye et al. 2012;Donio et al. 2013;Wang et al. 2013), systemic resistance inducers (Ongena et al. 2007), or insecticides (Geetha et al. 2010;Mnif et al. 2013). Before scaled-up purification was practical, development of bacterial lipopeptides was affected by a lack of information about the practical applications (e.g., field experiments), their affects on food security (e.g., acute toxicity tests), or advantages over agrochemicals (e.g., swarming motility tests or manufacturing increases of Bacillus-based BCA). ...
Agricultural application studies, including field experiments and acute toxicity tests, were conducted for lipopeptides secreted by marine-derived Bacillus marinus B-9987. Benefiting from commercially available scaled-up lipopeptide purification, the sample of impurities (isolated from target lipopeptides), raw extracted sample (purity: 9.08%), partially purified sample (purity: 20.86%), and highly purified sample (purity: 87.51%) were prepared from B. marinus B-9987 fermentation broth, and used in lab-scale antagonism tests, field experiments, swarming motility tests, and acute toxicity tests. Operations and conditions in field experiments were consistent with the Pesticide-Guidelines for the Field Efficacy Trials (GB/T 17980.28-2000), and acute toxicity tests were executed according to Toxicological Test Methods of Pesticides for Registration (GB 15670-1995). In agar diffusion tests in vitro and pot tests in vivo, all lipopeptide samples with different purities significantly inhibited Botrytis cinerea; meanwhile the sample of impurities isolated from target lipopeptides were not effective against B. cinerea. Results of lab-scale tests showed that the target lipopeptides were effective substances against B. cinerea. Thus, partially purified and raw extracted samples were used in field experiments instead of the highly purified sample for cost saving. In the field experiments against rose grey mold, biological control efficacy of 500 mg L⁻¹ lipopeptides reached 67.53%, slightly lower than 74.05% reached by the agrochemical pyrimethanil. However, pyrimethanil severely suppressed B. marinus B-9987, whereas the lipopeptides promoted swarming motility and biocontrol efficacy of Bacillus biomass. Lipopeptides at 87.51% purity were tested for systemic acute toxicity and confirmed as low-toxicity substances. In conclusion, low-toxicity lipopeptides were potential alternatives to agrochemicals, and they also performed good promotion when combined with homologous biological control microorganism. There were 2 breakthroughs in this research: (1) marine-derived bacterial lipopeptides inhibited grey mold caused by B. cinerea in field experiments; and (2) purified bacterial lipopeptides (sample purity: >87.51%) were determined to be low-toxicity substances by systemic acute toxicity tests, satisfying the strict requirement of pesticide registration in China (required purity: >85%). This study provides support for using extracellular Bacillus-derived lipopeptides commercially similar to Bacillus-based biological control agents.
... 1984 ;Pusey 1989), iturin A and surfactin (Asaka and Shoda 1996), as well as gramicidin S (Chandel et al. 2010;Che et al. 2015). Some of these produced cyclic AMPs which play a role in plant protection additionally display insecticidal activity, predominantly among these are the socalled lipopeptide biosurfactants which are utilised to further benefit plant production (Ghribi et al. 2012;Mnif et al. 2013). The latter includes surfactin which is insecticidal toward adult and larvae of the fruit fly Drosophila melanogaster , in contrast to coproduced iturin which shows no activity (Assie et al. 2002). ...
Tyrothricin is a peptide complex containing the linear gramicidins and cyclic tyrocidines. The tyrocidines have potent activity against fungal plant pathogens. As these peptides have possible agricultural applications, their toxicity was evaluated toward honey bee adults and larvae. Tyrothricin formulated in sucrose was non-toxic to caged adult honey bees at up to 1.5 g/L over 48-h exposure, which is 100- to 200-fold higher than the amount needed to eradicate high fungal loads (2 × 10⁴ spores/mL). Moreover, tyrothricin and the tyrocidines displayed potent in vitro activity toward foulbrood causing pathogens (Paenibacillus larvae, Melissococcus plutonius, Paenibacillus alvei) in honey bee larvae. In vivo tyrothricin or tyrocidine treatment delayed infection onset, indicating potential for curing. Tyrothricin was also found to be non-toxic with possible protective action in a semi-field trial on young bees released into hives, indicating the relative safety of the application of these antimicrobial peptides in an agricultural setting.
... Surface-active components, including biosurfactants, have been reported in B. subtilis, which act as effective fungicides against fungal diseases caused the Fusarium, Rhizoctonia, Alternaria and Aspergillus genera. B. sphaericus fungi have also shown insecticidal activity (Mnif et al., 2013;Chojnacka, 2015). ...
Biosurfactants which reduce the surface or interfacial tension of liquids and act as emulsifiers, foaming and dispersing agents with low toxicity, are increasingly finding applications in biotechnology and driving the search for novel compounds for further exploitation. Potential biosurfactants sourced from bacteria are often selected first by qualitative assessment of surface tension using simple assays such as the drop collapse technique or by quantitative tensiometry measuring air-liquid interfacial tension of cell-free culture supernatants or purified samples, and subsequently tested for appropriate physical-chemical behaviours using a range of application-specific assays. Highly active or strong biosurfactants have been reported to reduce the surface tension of water to approximately 22 - 25 mN.m-1, and show a range of behaviours determined by the choice of conditions (temperature, pH, salt concentration, etc.) used to test particular aqueous-hydrophobic (oil) mixtures. However, recent analyses of biosurfactant strengths using a predictive statistical approach (Individual Distribution Identification) have shown that it is unlikely that new compounds will be identified able to significantly reduce aqueous surface tensions below 24 mN.m-1. The mechanistic basis of this limit requires an explanation of why stronger compounds are not produced by bacteria, with a limitation of self-harm to producing cells probably the most likely biophysical explanation. However, behavioural analyses using a combination of emulsion, foam stability and oil-dispersion assays indicates high chemical diversity exists amongst biosurfactants exhibiting the strongest levels of activity (24 - 28 mN.m-1), suggesting that bacteria are still likely to provide a rich source of potentially novel compounds for use in biotechnology.
... Surface-active components, including biosurfactants, have been reported in B. subtilis, which act as effective fungicides against fungal diseases caused the Fusarium, Rhizoctonia, Alternaria and Aspergillus genera. B. sphaericus fungi have also shown insecticidal activity (Mnif et al., 2013;Chojnacka, 2015). ...
The instability of oil supply allied with the increasing environmental public awareness has raised interest in the development of alternatives to petroleum derivatives. In this sense, biosurfactants present an interesting opportunity since, apart from the potential to replace synthetic surfactants in industrial scale, they can be produced using low-value substrates, which is strongly aligned to the green chemistry concept. Mannosylerythritol lipid (MEL) is a glycolipid biosurfactant that has risen to prominence due to its high production yield and possible applications in different industries. MEL is a mixture of a partially acylated derivative of 4-O-β-D-mannopyranosyl-D-erythritol and can be classified as -A, -B, -C or -D taking exclusively into account the acetylation of C-4' and C-6' (mannose), although some other variants of MEL as mannosylmannitol lipids and tri-acylatedmannosylerythritol lipids have also been reported. Microbial MEL production has been reported in synthetic media as well as in agro-industrial residues using the fungi Pseudozyma sp., Ustilago sp., Schizonella melanogramma and Kurtzmanomyces sp. Traditionally, the purification steps of MEL are mainly undertaken through liquid extraction using ethyl acetate and silica column; nevertheless, the use of alternative methods such as ultrafiltration have also been described. Although the high hydrophobicity of MEL disfavors water-based applications, a wide range of potential uses have been described, such as (i) pharmaceutical drugs, (ii) bioremediation agents, (iii) cosmetic formulations, (iv) laundry detergent formulations, (v) antimicrobials. This chapter highlights the key features in MEL production as well as its applications and perspectives on future developments.
... Surface-active components, including biosurfactants, have been reported in B. subtilis, which act as effective fungicides against fungal diseases caused the Fusarium, Rhizoctonia, Alternaria and Aspergillus genera. B. sphaericus fungi have also shown insecticidal activity (Mnif et al., 2013;Chojnacka, 2015). ...
During last decades the interest on microbial surfactants or biosurfactants (BS) has gained attention due to their natural origin and environmental compatibility. These characteristics fulfill the demand of regulatory agencies and society to use of more sustained and green chemicals. Microbial-derived surfactants can replace synthetic surfactants in a great variety of industrial uses as detergents, foaming, emulsifiers, solubilizers and wetting agents. Actually, the main biotechnological application of biosurfactants is related to bioremediation and oil industry however, there is an increasing number of patents and research focusing the use of these molecules for pharmaceutical products and processes, suggesting that their potential as new ingredients is far from been entirely exploited. Bioremediation of pollutants such as organic contaminants and heavy metals present in soil and water can be improved by biosurfactants using bioaugmentation and biostimulation strategies. Biosurfactants also are useful for enhancing phytoremediation processes by increasing the bioavailability of heavy metals for plants. In pharmaceutical area, BS have shown antimicrobial, anti-biofilm, antitumor and immunomodulation activity among others. This review emphasizes current developments and applications of BS in environmental and health area.
... Surface-active components, including biosurfactants, have been reported in B. subtilis, which act as effective fungicides against fungal diseases caused the Fusarium, Rhizoctonia, Alternaria and Aspergillus genera. B. sphaericus fungi have also shown insecticidal activity (Mnif et al., 2013;Chojnacka, 2015). ...
Soil and water contamination associated with hydrocarbons is increasing every year due to hydrocarbon use in many industrial sectors. Physical, chemical and biotechnological processes are used to remove these contaminants. Bioremediation is one of the most important methods of removing hydrocarbons, wherein petrophilic microorganisms or their biosurfactants are used. These biological compounds have surface and interfacial activities and are mainly produced by microorganisms that are capable of degrading oil molecules, thereby increasing their mobility and availability to bacteria. The application of these metabolites is based on a lipophilic-hydrophilic balance. The metabolite structure, which depends on the type of bacteria that produces them, includes glycolipids (Alcanivorax borkumensis and Tsukamurella spp), rhamnolipids (Pseudomonas aeruginosa and Serratia rubidaea), sophorolipids (Torulopsis bombicola and Candida apicola) and trehalolipids (Rhodococcus erythropolis, Mycobacterium spp., Arthrobacter spp. and Nocardia spp). Interest in these compounds has significantly increased due to their potential industrial applications especially in environmental care (e.g., in restoring sites impacted by oil spills, in cleaning hydrocarbon bulk storage containers or as corrosion inhibitors). Unlike chemical surfactants, biosurfactants are able to produce more stable emulsions and have unique properties, including low toxicity and high biodegradability, selectivity and surface activity. These properties are retained even at high temperatures and wide pH and salinity ranges, which makes them attractive for enhanced hydrocarbon recovery processes. These biosurfactants could be applied to mature petroleum reservoirs, wherein residual crude oil recovery by conventional methods is unaffordable. Biosurfactants have the ability to modify the wettability of oil-storing rocks by reducing the surface and interfacial tension between oil and water, thereby facilitating oil recovery. Biosurfactants have been used in forest areas to address environmental problems in water, soil and sediments caused by oil spills and their derivatives. Specifically, biosurfactants have been applied in restoring mangrove forests contaminated with hydrocarbons, revitalizing multiple ecological and productive functions. Biosurfactants have also been used as stabilizing agents in producing Hevea brasiliensis rubber latex. Biosurfactants have also shown bioherbicide and antimicrobial activity. For example, biosurfactants have key applications as bioinsecticides, protecting the date palm (Phoenix dactylifera) against Ectomyelois ceratoniae. Thus, in addition to their use in mitigating hydrocarbon contamination, biosurfactants could be used to improve agrochemical and forestry processes.
... Related work evaluated the insecticidal activity of the biosurfactant of Bacillus subtilis (Ehrenberg) Cohn and found this to be effective for E . ceratoniae control (Mnif et al. 2013 ). Further work found the optimal medium for growing the biosurfactant, which may show promise for carob moth control. ...
Lepidopteran pest species attacking date palms and fruits are problematic in stored dates or in the date garden. Three such species, the carob moth, lesser date moth, and raisin moth, have biologies that are timed with the seasonal occurrence of date fruit. Thus they have become primary pests for the date producer and have been the focus of scientific research toward the development of sustainable management. This chapter provides an in-depth coverage of these three insects, with particular emphasis on their distribution, natural history, and management in date gardens.
... Different life stages of the carob moth have natural enemies from various groups of parasitoids, including Ichneumonoidea and Chalcidoidea (Kishani-Farahani et al., 2009), of which Trichogramma wasps have been released for pest control in pomegranate orchards (Nasrollahi et al., 1998). Among the insect pathogens, laboratory data are available about the potential of Bacillus subtilis (Ehrenberg) (Mnif et al., 2013) but the effect of other groups of insect pathogens and their pathogenicity against the carob moth have not yet been explored. Few studies have shown that entomopathogenic nematodes (EPN) have significant pathogenicity against different pest species from the Pyralidae family (Kaya and Gaugler, 1993;Grewal, 2002;Shapiro-Ilan and Gaugler, 2002;Lacey et al., 2015). ...
The carob moth (Ectomyelois ceratoniae) is the key pest of pomegranate, which causes a significant percentage of losses in pomegranate orchards and warehouses of Iran annually. The pest larvae are characterized by displaying a cryptic behavior within the fruit, which avoids most routine control techniques, especially chemical method. The low efficiency of traditional measurements and also the rich species diversity of natural enemies within the infested fruits highlight the necessity of exploring effective control methods, especially environmental friendly approaches. Entomopathogenic nematodes (EPNs) are a group of biological control agents that actively search for the host, including those in a cryptic habitat like the carob moth larvae within infested fruits. Here, we assumed that treatment of the infested and dropped fruits with EPNs may provide new insight into the management of the carob moth. Three species of EPNs, Steinernema feltiae, S. carpocapsae, and Heterorhabditis bacteriophora were selected and used in a series of in vitro and in vivo experiments. In preliminary assays, the EPNs species were used with different concentrations of infective juveniles (IJs) (0, 1, 5, 10, 25, and 50 IJ/larvae) in 2-cm diam. plates. The mortality rates of the laboratory tests were 79.75% and 76.5% for S. feltiae and S. carpocapsae, corresponded to LC 50 value of 2.02 IJ/larva for S. feltiae and 2.05 IJ/larva for S. carpocapsae. On the contrary, H. bacteriophora demonstrated low virulence on the pest larvae in petri tests with a LC 50 = 426.92 IJ/larva. Hence, both Steinernema species were selected for subsequent experiments. The penetration rate for S. feltiae and S. carpocapsae into the hemocoel of the pest was 43% and 31%, respectively, and the corresponding reproduction rate was 15,452 IJ/larva for S. feltiae and 18,456 IJ/larva for S. carpocapsae. The gathered data from those in vitro tests were used for a field assay. Different concentrations (5, 10, 50, 100, and 160 IJ/cm 2 of the arena) of S. feltiae and S. carpocapsae were applied in the field test. The mean mortality results from the last test were 10.89% and 26.65% for S. feltiae and S. carpocapsae, respectively. Finally, we found that these low virulence rates of the nematodes were attributed to inhibitory/repellency effects of saprophytic fungi within the infested pomegranates, a usual status of the infested fruits in autumn or winter seasons. Future work on additional EPN populations more adapted to the extreme conditions of the pomegranate production area in Iran may provide sufficient evidence to continue the further investigation on the best EPN species populations and advanced formulations with high durability.
... The global biocontrol market of these BCAs was expected to rise to 3-4 billion US dollars by 2017 (Velivelli et al. 2014). However, Bacillus-derived lipopeptides have rarely been developed commercially as fungicides (Wei et al. 2010;Ye et al. 2012;Donio et al. 2013;Wang et al. 2013), systemic resistance inducers (Ongena et al. 2007), or insecticides (Geetha et al. 2010;Mnif et al. 2013). Before scaled-up purification was practical, development of bacterial lipopeptides was affected by a lack of information about the practical applications (e.g., field experiments), their affects on food security (e.g., acute toxicity tests), or advantages over agrochemicals (e.g., swarming motility tests or manufacturing increases of Bacillus-based BCA). ...
This research was aimed at establishing the pilot-scale purification technology of lipopeptide from marine-derived Bacillus marinus. We studied lipopeptide surfactivity interferences on scale-up unit technologies including acid precipitation, methanol extraction, solvent precipitation, salting out, extraction, silica gel column chromatography and HZ806 macroporous absorption resin column chromatography. Then, the unit technologies were combined in a certain order, to remove the impurities gradually, and to gain purified lipopeptide finally, with high recovery rate throughout the whole process. The novel pilot-scale purification technology could effectively isolate and purify lipopeptide with 87.51% to 100% purity in hectograms from 1 ton of Bacillus marinus B-9987 fermentation broth with more than 81.73% recovery rate. The first practical hectogram production of highly purified lipopeptide derived from Bacillus marinus was achieved. With this new purification method, using complex media became possible in fermentation process to reduce the fermentation cost and scale-up the purification for lipopeptide production. For practicability and economy, foaming problem resulting from massive water evaporation was avoided in this technology.
... Luna et al. (2011) evaluated biosurfactant production by Candida sphaerica UCP 0995 through factor planning and found a surface tension of 25.25 mN/m for the cell-free broth. Mnif et al. (2013) also report the production of a biosurfactant using experimental planning, demonstrating the empirical relationships among the combinations of variables studied. The elliptical nature of the response surface graphs indicated the importance of interactions among the corresponding variables. ...
The production of surfactants by microorganisms has become an attraction option, as biosurfactants are biodegradable and less toxic than synthetic surfactants, although the production costs remain high. With the aim of reducing the cost of biosurfactant production, three strains of Pseudomonas (designated P1, P2 and P3) were cultivated in a low-cost medium containing molasses and corn steep liquor as substrates. Following the selection of the best producer (P3), a rotational central composite design (RCCD) was used to determine the influence of substrates concentration of on the surface tension and biosurfactant yield. The biosurfactant reduced the surface tension of water to 27.5 mN/m and its CMC was determined as 600 mg/L. The yield was 4.0 g/L. The biosurfactant demonstrated applicability under specific environmental conditions and was able to remove 80-90% of motor oil adsorbed to sand. The properties of the biosurfactant suggest its potential application in the bioremediation of hydrophobic pollutants.
Agricultural productivity is serious concern for all the developing countries to meet the emerging needs of the human population. There is requirement of green compounds to achieve the productive agriculture and worldwide an average of 35% of crop yield is lost due to preharvest pest. Today, the commonly produced chemical pesticides in agriculture are still under stress to be excluded from the market due to their hazardous effect on the ecosystem, and resistance by bacteria and fungi also poses a significant barrier to their use.In recent times, biosurfactants have become one of the promising biopesticides. The biopesticides have gained attention in the management of fungi, pest, and insects, and have long been boosted as potential alternative of chemical pesticide. The scientific reports have stated the use of microbial biosurfactant in disease control of fungi, pest insects, and Induced Systemic Resistance. Lipopeptide and rhamnolipid biosurfactants are low in toxicity to the ecosystem and highly biodegradable in nature and promising surface-active compound that could be used as biopesticides. Until now, rhamnolipid biosurfactants have been studied and successfully commercialized for biopesticide application. The increased environment concern on pesticide and agrochemical provides incitement for the requirement of eco-friendly chemicals in the agrochemical industries, where biosurfactant may be the best alternative. This chapter reviews the lipopeptide and rhamnolipid biosurfactant as biopesticides and promising alternatives to chemical pesticides.KeywordsRhamnolipidLipopeptideBiopesticideAgrochemicalsBiosurfactants
The biosurfactants produced by microorganisms have high demand from microbial-enhanced oil recovery (MEOR) and they have focused on a chemical surfactant for the past few decades for degrading petro-based pollutants and oil spills due to its non-toxicity and increasing bioavailability. The study aims to identify and screen potential lipopeptide biosurfactant produced by Paenibacillus species employing a design experiment based on RSM. The bacterial culture was isolated from Chilika Lake, India. The data generated from the biosurfactant stability experiments were used to fit a regression model using the parameters such as ph, temp, and salinity to predict the E24 index. R-squared value 0.91 obtained from the ANOVA model explains that the regression model was significant, and the model p-value obtained was < 0.05 and was also statistically significant. Therefore the statistical regression model obtained in the present investigation can predict the E24 index by using any combination of ph, temp, and salinity parameters. The novel isolates obtained in this research were further named Paenibacillus dendritiformis ANSKLAB02 and deposited in GenBank with accession number KU518891. The growth of this species under controlled conditions has a high potential to help in environmental clean-up and is suitable for use in MEOR applications.
Detergent products are a formulated mixture of ingredients with a washing or cleaning power. The most active compounds involved in the cleaning process are the so-called surfactants; amphiphilic compounds with polar head and an-polar teal. They have the property to lower the surface tension (ST) of water, to adsorb to the interface and to reduce the interfacial tension (IFT) between two immiscible liquid. Then, they are very good at liberating dirt and to eliminate impurities. However, owing their chemical nature, they are characterized by their high toxicity and low biodegradability causing serious risks to natural ecosystems. Therefore, an urgent need was developed for the production of environment friendly detergent. Thus, developing eco-friendly, nonirritant, low-toxic, and high-efficient surface active ingredients for detergents is an ongoing challenge in the detergent field. To know, biosurfactants (BioS) or microbial surfactants are amphiphilic compounds having the ability to reduce the surface and interfacial tension. They are characterized by their higher biodegradability, low toxicity and eco-friendly. Thus, they can be the best substitutes of chemical surfactants in detergent formulation permitting the development of eco-friendly bio-based detergent formula. With this aim, we will discuss in the first part of the presented review detergent formula and surfactants as the base ingredients; their physic-chemical properties and higher toxicity. In the second part of the review paper, BioS as emerging ingredients for detergent formulation will be presented; their classification, physic-chemical and functional properties along with their potential application in detergent formulation.
Bacillus sp. PHP1601 (Bacillales: Bacillaceae), a member of the B. subtilis sensu lato, possesses an interesting ability to antagonise fly larvae. Blowflies are considered occupational nuisances and recognised as vectors of disease. A study was undertaken to evaluate the biocontrol potential of Bacillus sp. PHP1601 against Lucilia cuprina (Wiedemann) (Diptera, Calliphoridae) larvae. Bioassays were established to determine the biocontrol efficacy of various treatment formulations, i.e., vegetative cell (102–1010 cells g−1), endospore (102–1010 endospores g−1), cell-free supernatant (1–30% v w−1) and crude biosurfactant extract (5–1000 μg g−1) against second instar L. cuprina fly larvae reared on milk agar medium. All treatments demonstrated a dose-dependent larvicidal response over a 240 h period. Even at the lowest cell and endospore concentrations tested (i.e., 102 cells/endospores g−1) the pupation stage was inhibited, effectively interrupting the fly reproduction cycle. Larvae antagonism elicited by partially purified biosurfactant extracts indicated the likely contribution of bioactive lipopeptide compounds to the mechanism of inhibition. Larvae cadavers recovered from these treatments displayed substantial physiological discolouration and lacked structural integrity. PHP1601 was confirmed to be a strain of B. velezensis based on multiple-locus sequence analysis of 16S rRNA, gyrA, rpoB and dnaJ housekeeping genes. This study constitutes the first report of a strain of B. velezensis demonstrating a larvicidal response towards a member of the suborder Brachycera.
The biosurfactants produced by microorganisms have high demand from microbial-enhanced oil recovery (MEOR) and they have focused on a chemical surfactant for the past few decades for degrading petro-based pollutants and oil spills due to its non-toxicity and increasing bioavailability. The study aims to identify and screen potential lipopeptide biosurfactant produced by Paenibacillus species employing a design experiment based on RSM. The bacterial culture was isolated from Chilika Lake, India. The data generated from the biosurfactant stability experiments were used to fit a regression model using the parameters such as ph, temp, and salinity to predict the E24 index. R-squared value 0.91 obtained from the ANOVA model explains that the regression model was significant, and the model p-value obtained was < 0.05 and was also statistically significant. Therefore the statistical regression model obtained in the present investigation can predict the E24 index by using any combination of ph, temp, and salinity parameters. The novel isolates obtained in this research were further named Paenibacillus dendritiformis ANSKLAB02 and deposited in GenBank with accession number KU518891. The growth of this species under controlled conditions has a high potential to help in environmental clean-up and is suitable for use in MEOR applications.
The biosurfactants produced by microorganisms have high demand from microbial-enhanced oil recovery (MEOR) and they have focused on a chemical surfactant for the past few decades for degrading petro-based pollutants and oil spills due to its non-toxicity and increasing bioavailability. The study aims to identify and screen potential lipopeptide biosurfactant produced by Paenibacillus species employing a design experiment based on RSM. The bacterial culture was isolated from Chilika Lake, India. The data generated from the biosurfactant stability experiments were used to fit a regression model using the parameters such as ph, temp, and salinity to predict the E24 index. R-squared value 0.91 obtained from the ANOVA model explains that the regression model was significant, and the model p-value obtained was < 0.05 and was also statistically significant. Therefore the statistical regression model obtained in the present investigation can predict the E24 index by using any combination of ph, temp, and salinity parameters. The novel isolates obtained in this research were further named Paenibacillus dendritiformis ANSKLAB02 and deposited in GenBank with accession number KU518891. The growth of this species under controlled conditions has a high potential to help in environmental clean-up and is suitable for use in MEOR applications.
Biosurfactants, in comparison to chemical surfactants, have a greater impact on various applications due to their stability, degradability, and other physicochemical characteristics. Increasing yield and lowering production costs are critical to enhancing biosurfactant efficiency. Because biosurfactant production costs are determined by the least expensive substrate, agro-based industrial waste is one of the most promising economic strategies. Therefore, in this study we aimed to achieve the biosurfactant production in Pseudomonas aeruginosa by low cost rice medium using Response surface methodology (RSM) and assessed their competence in controlling the Fusarium wilt of Abelmoschus esculentus. Initially, the selected strain P. aeruginosa PBS29 was confirmed using 16S rRNA sequencing. Then, the 20 % (v/v) of rice water was chosen as the cheapest carbon source for formulating rice water medium to optimize biosurfactant production using Central Composite Design. Enhanced biosurfactant yield of 9.35 g/l was attained through RSM by 0.59 fold higher than preliminary analysis. The model was significant with a regression coefficient of 0.98. The optimal condition was identified as 1.18% (w/v) nitrogen source [glutamic acid], pH 6.8, temperature at 37.4 °C, 2.5% (v/v) inoculum size, and 167.9 rpm agitation. In-vitro antifungal activity and biocontrol strategy of the biosurfactant demonstrated against Fusarium wilt of Abelmoschus esculentus at 100 μg/ml concentration by both soil drenching and foliar spray by pot trial. Furthermore, the detection of rhl gene, TLC, FT-IR, HPLC and GC-MS analyses suggested that the biosurfactant is rhamnolipid. Overall, in this study, the biosurfactant was synthesized using inexpensive rice water and substantiated its safe use as a biocontrol agent, which will help large-scale commercialization and interchange chemical surfactant used in agricultural wastes.
The bio-surfactants produced by microorganisms have high demand from microbial-enhanced oil recovery (MEOR) and they have focused on a chemical surfactant for the past few decades for degrading petro-based pollutants and oil spills due to its non-toxicity and increasing bioavailability. These microorganisms can survive over the different oil species and contaminants that lead to their degradation with carbon dioxide and water as the remnants. The study aims to identify and screen potential lipopeptide biosurfactant produced by Paenibacillus species employing a design experiment based on response surface methodology (RSM) . The bacterial culture was isolated from India's most significant brackish water, Chilika Lake. It screened using various protocols, including oil spread assay, BATH, drop collapse assay, hydrocarbon overlay agar method, E24, etc. The acid precipitation performed to extract the biosurfactant produced by isolate succeeding solvent recovery. 0.426g of biosurfactant per 100ml medium was obtained from the isolated novel Paenibacillus dendritiformis strain (C50H87N7O13), having a molecular weight of 999.300g/mol. The highest yield is attained at emulsification activity (E24 = 73.37%), having optimized environmental parameters (pH- 7, temp- 30°C and 4% salinity) using crude oil as the sole carbon source. The isolated novel strain owing an advantage in improving bioremediation of PAH (polycyclic aromatic hydrocarbons) and efficiently impact the environmental contaminants due to its high lipopeptide concentration up to a threshold level. Based on the Box-Behnken experimental design, the E24 values were varied from 24.6% to 73.3%, and the highest E24 was observed for pH 7, temperature 30°C and 4% salinity. The data generated from the biosurfactant stability experiments were used to fit a regression model using the parameters such as ph, temp and salinity to predict the E24 index. R-squared value 0.91 obtained from the annova model explains that the regression model was significant, and the model p-value obtained was < 0.05 and was also statistically significant. Therefore the statistical regression model obtained in the present investigation can predict the E24 index by using any combination of ph, temp and salinity parameters. Molecular characterization of the isolate was carried out by 16S rRNA gene sequencing using Sanger dideoxy sequencing followed by a phylogenetic assessment. The isolate was found to be a novel strain of Paenibacillus dendritiformis , further named Paenibacillus dendritiformis ANSKLAB02. The novel isolates obtained in this research was deposited in GenBank with accession number KU518891. The present study contributes to the list of such microbial factories by introducing a new strain of Paenibacillus dendritiformis . The growth of this species under controlled conditions has a high potential to help in environmental clean-up and is suitable for use in MEOR applications.
Purpose: Heterorhabdits indica successfully controlled apple root borer Dorysthenes huegelii in the orchards, but nematode-infected cadavers revealed the presence of non-symbiotic bacteria B. subtilis and B. licheniformis, and no subsequent generations of H. indica were produced (hampered recycling phenomenon). Intrigued, we tested the effect of the two Bacillus species on symbiotic association of H. indica - Photorhabdus luminescens.
Methods: One-to-one competitive parallel line in vitro assays were carried out between P. luminescens and the two Bacillus spp., while in vivo H. indica development was studied on the test insect Galleria mellonella which were fed with Bacillus mixed diet, followed by nematode exposure.
Results: Where P. luminescens was flanked by either of the two Bacillus species, only B. subtilis significantly suppressed its growth, while in reversed assays both the Bacillus growth was unaffected. Heterorhabditis indica was able to kill Galleria larvae pre-fed with the two Bacillus spp.; these cadavers did not develop the characteristic evenly distributed brick red coloration. Besides P. luminesecns, both Bacillus spp. were found to coexist in these cadavers. Development of hermaphrodites was not affected, but second-generation females, and final nematode progeny was reduced significantly. Monozenic lawns of B. subtilis and B. licheniformis did not support H. indica development.
Conclusion: These results show the reduced development of H. indica by the presence of the non-symbiotic bacteria in G. mellonella is likely to affect their ability to recycle in other insect larvae. Reduced recycling caused by non-symbiotic bacteria will reduce the overall long-term pest control benefits and have implications in the development of application strategies using entomopathogenic nematodes (EPNs) as insect control agents.
Nowadays, the worldwide search regarding renewable products from natural resources is increasing due to the toxicity of chemical counterparts. Biosurfactants are surface-active compounds that contain several physiological functions that are used in industries like food, pharmaceutical, petroleum and agriculture. Microbial lipopeptides have gained more attention among the researchers for their low toxicity, efficient action and good biodegradability when compared with other surfactants. Because of their versatile properties, lipopeptide compounds are utilized in the remediation of organic and inorganic pollutants. This review presented a depth evaluation of lipopeptide surfactants in the bioremediation process and their properties to maintain a sustainable environment. Lipopeptide can acts as a replacement to chemical surfactants only if they meet industrial-scale production and low-cost substrates. This review also demonstrated the production of a lipopeptide biosurfactant from a low-cost substrate and depicted plausible techniques to manage the substrate residues to determine its ability in the different applications particularly in the bioremediation process.
Crude oil and its derivatives are the most important pollutants in natural environments. Bioremediation of crude oil using bacteria has emerged as a green cleanup approach in recent years. In this study, biosurfactant-producing Bacillus subtilis strain Al-Dhabi-130 was isolated from the marine soil sediment. This organism was cultured in solid-state fermentation using agro-residues to produce cost-effective biosurfactants for the bioremediation of crude-oil contaminated environments. Date molasses improved biosurfactant production and were used for further optimization studies. The traditional “one-variable-at-a-time approach”, “two-level full factorial designs”, and a response surface methodology were used to optimize the concentrations of date molasses and nutrient supplements for surfactant production. The optimum bioprocess conditions were 79.3% (v/w) moisture, 34 h incubation period, and 8.3% (v/v) glucose in date molasses. To validate the quadratic model, the production of biosurfactant was performed in triplicate experiments, with yields of 74 mg/g substrate. These findings support the applications of date molasses for the production of biosurfactants by B. subtilis strain Al-Dhabi-130. Analytical experiments revealed that the bacterial strain degraded various aromatic hydrocarbons and n-alkanes within two weeks of culture with 1% crude oil. The crude biosurfactant produced by the B. subtilis strain Al-Dhabi-130 desorbed 89% of applied crude oil from the soil sample. To conclude, biosurfactant-producing bacterial strains can increase emulsification of crude oil and support the degradation of crude oil.
Surfactants are multipurpose products found in most sectors of contemporary industry. Their large-scale manufacturing has been mainly carried out using traditional chemical processes. Some of the chemical species involved in their production are considered hazardous and some industrial processes employing them categorised as “having potential negative impact on the environment”. Biological surfactants have therefore been generally accepted worldwide as suitable sustainable greener alternatives. Biosurfactants exhibit the same functionalities of synthetic analogues while having the ability to synergize with other molecules improving performances; this strengthens the possibility of reaching different markets via innovative formulations. Recently, their use was suggested to help combat Covid-19. In this review, an analysis of recent bibliography is presented with descriptions, statistics, classifications, applications, advantages, and challenges; evincing the reasons why biosurfactants can be considered as the chemical specialities of the future. Finally, the uses of the solid-state fermentation as a production technology for biosurfactants is presented.
Biosurfactants are amphipathic molecules synthesized by microorganisms (bacteria, yeasts, and filamentous fungi) that exhibit surface‐active (biotensoactives) and/or emulsifying (bioemulsifiers), antimicrobial, and antitumor properties. The number of studies on the production of biological surfactants has increased significantly due to the features and benefits of these products over synthetic surfactants. Their eco‐friendly characteristics, such as low toxicity, biodegradability, possibility of being produced from inexpensive and renewable raw materials, diversity of applications and functionality under extreme conditions, make these versatile molecules promising for the future. In this chapter, we present aspects related to the basic concepts of surfactants, microbial and enzymatic synthesis of biosurfactants, conventional and nonconventional raw materials, applications in various industrial sectors, and sustainable production in the context of lignocellulosic biorefineries. Thus, it is intended to show that biosurfactants are versatile molecules, with high added value and fit in the context of sustainable development that is transforming society and science.
An efficient biosurfactant-producing strain was isolated and cultured from Dagang oil field (China) using crude oil as sole source of carbon. Based on partial sequenced 16S rDNA analysis, the isolated strain was identified as Pseudomonas aeruginosa SNP0614. The bacterium P. aeruginosa SNP0614 produced a type of biosurfactant with excessive foam-forming properties. After microbial cultivation at 37°C and 150 rpm for 12 h, the produced biosurfactant was found to reduce the surface tension to 25.4 mN/m with critical micelle concentration (CMC) of 45.0 mg/L. After 20 days of incubation, the biosurfactant exhibited 90% emulsification activity (E24) on crude oil. FTIR spectroscopy of extracted biosurfactant indicated the biosurfactant as lipopeptide. The significant synergistic effect between P. aeruginosa SNP0614 and the mixed oildegrading bacteria resulted in increasing n-alkanes degradation rate by 30%. The strain P. aeruginosa SNP0614 represented as a promising biosurfactant producer and could be applied in a variety of biotechnological and industrial processes, particularly in microbial enhanced oil recovery and the bioremediation of oil pollution.
Ectomyeolis ceratoniae Zeller (Lepidoptera: Pyralidae), carob moth, is a pest of several crops in South Africa. A laboratory culture was established from field-collected larvae infesting mummified pecan nuts. Biological parameters of larvae reared on an artificial diet were measured. The insect goes through five larval instars, and the head capsule sizes of the five instars were determined to be ≤0.34 mm, 0.35-0.64 mm, 0.65-0.94 mm, 0.95-1.14 mm and ≥0.15 mm for the five instars, respectively. The insect was reared individually and communally in glass vials, the latter to develop a mass-rearing technique. Developmental time from neonate to pupa was significantly slower when larvae were individually reared (38.18 ± 1.2 days) compared to when they were communally reared (24.6 ± 0.65 days).Amicrosporidian infection (Nosema sp.) was recorded in the culture, causing significantly (F1,6 = 14.99, P = 0.0082) higher mortality of communally reared larvae (76.25 % ± 11.87) than individually reared larvae (24.9 % ± 9.6).
Laboratoire de Protection des Végétaux, INRAT, 2080 Ariana, Université de 7 Novembre à Carthage, Tunisia, and Mohamed Larbi Khouja, Laboratoire d'Ecologie et Amélioration Sylvo-Pastorale, INRGREF, 2080 Ariana, Université de 7 Novembre à Carthage, Tunisia __________________________________________________________________________ ABSTRACT Haouel, S., Mediouni-Ben Jemâa, J., and Khouja, M.L. 2010. Postharvest control of the date moth Ectomyelois ceratoniae using eucalyptus essential oil fumigation. Tunisian Journal of Plant Protection 5: 201-212. This work aims to investigate the chemical composition and to assess for the first time the fumigant toxicity of two eucalyptus (Eucalyptus camaldulensis and E. rudis) essential oils against the date moth Ectomyelois ceratoniae in storage as alternative to methyl bromide. GC-MS analyses showed that E. rudis essential oil presented α-pinene (14.49%), 1,8-cineole (19.87%), β-pinene (3.91%), γ-terpinene (6.04%), terpinene-4-ol (4.46%) and α-terpineol (4.32%) as major compounds whereas, E. camaldulensis essential oil had α-pinene (16.49%), 1,8-cineole (20.62%), γ-terpinene (4.08%), terpinene-4-ol (4.45%), aromadendrene (3.93%) and isothymol (7.3%) as major compounds. Results showed that fumigant toxicity depends on oil species, concentrations and exposure time. The fumigant toxicity potential of E. rudis (LC 50 = 31.37 µl/l air) was greater than E. camaldulensis (LC 50 = 34.08 µl/l air). Moreover, the median lethal time values (LT 50) were 36.10 and 48.84 h, respectively. Results suggested that E. rudis and E. camaldulensis essential oils could be used as an alternative to the synthetic fumigant in postharvest treatment program for the control of E. ceratoniae.
This paper reports results of the first cytogenetic investigation carried out in the carob moth, Ectomyelois ceratoniae Zeller, the serious polyphagous pest of both stored products and field crops in the Mediterranean basin and Near East regions. Preparations of mitotically dividing spermatogonia and oogonia revealed that the carob moth karyotype consists of 2n = 62 chromosomes. As typical for Lepidoptera, the chromosomes were of a holokinetic type, only slightly differed in their sizes, and displayed no morphological structures including primary constrictions (the centromeres) that could enable us their identification. Metaphase I spermatocytes showed 31 bivalents. Accordingly, 31 chromosome elements were observed in metaphase II spermatocytes. Hence the haploid chromosome number is n = 31. In pachytene complements, two NOR bivalents were observed. In highly polyploid nuclei of the Malpighian tubule cells and silk glands, females showed a heterochromatin body, the so-called sex chromatin or W chromatin, that was absent in male nuclei. This indicated that the carob moth possesses a WZ/ZZ sex chromosome system. However, we failed to identify the sex chromosome bivalent WZ in pachytene oocytes. In order to differentiate the sex chromosomes, we employed genomic in situ hybridization (GISH) and comparative genomic hybridization (CGH). GISH detected the W chromosome by strong binding of the Cy3-labelled, female-derived DNA probe. With CGH, both the Cy3-labelled female-derived probe and Fluor-X labelled male-derived probe evenly bound to the W. This suggested that the W is composed predominantly of repetitive DNA sequences occurring scattered in other chromosomes but accumulated in the W chromosome.
An artificial diet for rearing the carob moth Ectomyelois ceratoniae Zeller was developed composed of wheat bran, yeast, sucrose, salt mixture, vitamin C, aureomycine, methyl paraben, lysine, glycerine and distilled water. Carob moths, mass-reared on this artificial diet showed a similar performance to moths reared on this diet as single pairs with respect to larval developmental time, percent adult emergence, adult weight, longevity, percentage egg hatch and sex ratio. However, fecundity and fertility of adults reared on the artificial diet was significantly lower than single-pair reared moths. In addition, an assessment was made of the propensity of male carob moths to respond to the female pheromone during field cage studies using non-irradiated and irradiated males in the presence of virgin non-irradiated females. The data indicated that irradiated males responded equally well to the virgin females as untreated males, irrespective of the male ratio. The dispersal of partially sterile carob moth males was assessed in a pomegranate orchard using mark-release-recapture tests.Asimilar dispersal between irradiated and normal males was observed for distances between 40 to 80 metres from the release point. Significant differences between dispersal of irradiated versus untreated males were obtained for distances exceeding 100 metres from the release point.
KEYWORDS sterile insect technique, artificial diet, rearing, inherited sterility, dispersal, markrelease- recapture, pomegranate, Ectomyelois ceratoniae, carob moth, Tunisia
During the last years, several applications of biosurfactants with medical purposes have been reported. Biosurfactants are considered relevant molecules for applications in combating many diseases. However, their use is currently extremely limited due to their high cost in relation to that of chemical surfactants. Use of inexpensive substrates can drastically decrease its production cost. Here, twelve solid substrates were screened for the production of Bacillus subtilis SPB1 biosurfactant and the maximum yield was found with millet. A Plackett-Burman design was then used to evaluate the effects of five variables (temperature, moisture, initial pH, inoculum age, and inoculum size). Statistical analyses showed that temperature, inoculum age, and moisture content had significantly positive effect on SPB1 biosurfactant production. Their values were further optimized using a central composite design and a response surface methodology. The optimal conditions of temperature, inoculum age, and moisture content obtained under the conditions of study were 37°C, 14 h, and 88%, respectively. The evaluation of the antimicrobial activity of this compound was carried out against 11 bacteria and 8 fungi. The results demonstrated that this biosurfactant exhibited an important antimicrobial activity against microorganisms with multidrug-resistant profiles. Its activity was very effective against Staphylococcus aureus, Staphylococcus xylosus, Enterococcus faecalis, Klebsiella pneumonia, and so forth.
The present investigation aimed to throw light on the effect of Bacillus subtilis SPB1 biosurfactant on the third larval instars of the Mediterranean flour moth, Ephestia kuehniella, under laboratory conditions. The toxicity of this compound was investigated with emphasis on histopathological effects in the midgut of larvae. The tested dose levels showed strong histopathological disturbances in the midgut of this pest. The most frequently observed effects were cell vacuolisa-tion, microvilli damage and epithelium cell contents passing into the midgut lumen. The present study was also extended to improve the insecticidal activity of the SPB1 biosurfactant against E. kuehniella larvae through optimisation of the pH of the biosurfactant solution and the incubation temperature using Central Composite Design. The experimental results were fitted to a second-order polynomial model that yielded a determination coefficient of R 2 = 0.998. The optimal insecticidal activity conditions were found to be a temperature of 33.20°C and pH of 6.66. The predicted and observed responses were 200.4 ng mg -1 and 182.57 ng mg -1, respectively. In comparison to the original LC 50 level, a 30% decrease was obtained.
Biosurfactants are currently not a feasible alternative to chemically synthesized surfactants as a result of their potentially high production costs. In this work, Bacillus subtilis SPB1 biosurfactant was shown to be efficient in the biocontrol of the olive moth Prays oleae. Its production was improved by optimizing the medium components using inexpensive substrates. The effect of orange peels, soya bean and diluted sea water on SPB1 biosurfactant production was studied and was adjusted using central composite design. The experimental results were fitted to a second-order polynomial model that yielded a determination coefficient of R2=0.932. The optimal medium for biosurfactant production was found to be composed only by orange peels (15.5 g/L), soya bean (10 g/L) and diluted sea water (30%). The predicted and observed response were 4.3 g/L (with desirability = 0. 21) and 4.45 g/L, respectively. In comparison to original level production, two fold increases had been obtained.
A cyclic lipopeptide, surfactin produced by a strain of Bacillus subtilis subsp. subtilis (VCRC B471) was found to exhibit activity against both the larval and pupal stages of mosquitoes. The present study was aimed at increasing the production of the mosquitocidal metabolite by modifying the conventional medium.
Enhancement of mosquitocidal metabolite production was attempted by replacing the existing micronutrients of the conventional NYSM and supplementing the medium with additional amounts of glucose. The LC₅₀ value of culture supernatant (CS) against the larval and pupal stages of Anopheles stephensi was determined. Crude mosquitocidal metabolite (CMM) was separated from the CS, identified by MALDI-TOF analysis and its LC₅₀ dosage requirement for the pupal stage of the above mosquito species determined.
The medium containing a new composition of micronutrients and glucose up to 1 per cent resulted in increased metabolite production. The LC₅₀ value of the CS obtained in the improved medium against larvae and pupae of An. stephensi was 5.57 and 0.71 μl/ml, respectively. The yield of CMM was doubled in the improved medium. MALDI-TOF analysis revealed that the CMM was surfactin.
The new improved medium enhanced the production of mosquitocidal metabolite as the dosage required for inciting 50 per cent mortality among the pupal stages of mosquitoes was only half of that required when the metabolite was produced in the conventional medium. The mosquitocidal metabolite was identified as surfactin, a cyclic lipopeptide and biosurfactant.
The rpoB gene of the mosquito pupicidal isolate Bacillus subtilis (VCRC B471) was amplified to confirm the subspecies as subtilis. The mosquito pupicidal activity expressed by the biosurfactant surfactin is novel, and hence, the influence of abiotic factors like pH, temperature of water and sunlight on its efficacy was studied under laboratory conditions.
The rpoB gene amplicon of the bacterium (c. 570 bp of) was sequenced (accession number: EU057603). The relatedness of the bacterium to other members of the genus Bacillus was studied by tree construction, and the identity of VCRC B471 was confirmed as B. subtilis ssp. subtilis. The mosquito pupicidal activity exhibited by surfactin was found to be unaffected between pH 3-9, temperatures 25 and 37 °C and exposure to sunlight/UV radiation. Further, the pupicidal activity of surfactin was not diminished after exposure to 121 °C for 15 min, indicating its thermostable nature.
VCRC B471 is confirmed as a strain of B. subtilis ssp. subtilis. The mosquitocidal toxin, surfactin produced by this bacterium being stable to UV and varied temperature, active at acidic and basic pH and temperatures between 25 and 42 °C renders this molecule an interesting lead to be developed as a mosquitocidal agent.
The mosquitocidal toxin, surfactin produced by B. subtilis ssp. subtilis (VCRC B471), being a biodegradable biosurfactant, exhibiting high stability to varied environmental conditions, can be used year round in breeding habitats and will be a prospective microbial toxin for use against mosquitoes.
Bacillus thuringiensis subsp. medellin produces numerous proteins among which 94 kDa known as Cry11Bb, has mosquitocidal activity. The mode of action of the Cry11 proteins has been described as similar to those of the Cry1 toxins, nevertheless, the mechanism of action is still not clear. In this study we investigated the in vivo binding of the Cry11Bb toxin to the midgut of the insect species Anopheles albimanus, Aedes aegypti, and Culex quinquefasciatus by immunohistochemical analysis. Spodoptera frugiperda was included as negative control. The Cry11Bb protein was detected on the apical microvilli of the midgut epithelial cells, mostly on the posterior midgut and gastric caeca of the three mosquito species. Additionally, the toxin was detected in the Malpighian tubules of An. albimanus, Ae. aegypti, Cx. quinquefasciatus, and in the basal membrane of the epithelial cells of Ae. aegypti midgut. No toxin accumulation was observed in the peritrophic membrane of any of the mosquito species studied. These results confirm that the primary site of action of the Cry11 toxins is the apical membrane of the midgut epithelial cells of mosquito larvae.
Publisher Summary This chapter discusses the biochemical engineering aspects of solid-state fermentation (SSF). Solid-state fermentation involves the growth of microorganisms on moist solid substrate in the absence of free-flowing water. The necessary moisture in SSF exists in an absorbed or complexed form within the solid matrix, which is likely to be more advantageous because of the possible efficient oxygen transfer process. Most applications of fermentation for the manufacture of industrial products use technology based on submerged fermentation; solid-state fermentation techniques are seen to exhibit great potential and for specific cases, competitive SSF systems have already been developed. Some of the important aspects on which research efforts need to be focused in this area are (1) the development of mathematical models accounting for the interactions of transport of heat and mass with bioreaction kinetics in different types of SSF systems; (2) theoretical predictions and experimental determination of transport parameters for SSF; (3) the development of reliable estimation methods, in particular for biomass in the presence of solids; and (4) better design of bioreactors enablingaccurate measurement and control of variables such as temperature, gaseous concentration, and water activity. To develop an effective SSF process, an interdisciplinary effort involving a combination of microbiological and engineering aspects is essential.
Zoospore-producing oomycetes are major plant pathogens of particular concern in hydroponic systems. Compared with pesticides, biocontrol using antagonistic microorganisms is a sustainable approach to control oomycetes. Previous research has demonstrated that biosurfactants and biosurfactant-producing microorganisms are potentially useful components of a sustainable biocontrol strategy.In this study three ways of supplying a biosurfactant-producing strain to a recirculating hydroponic cultivation system infected with a zoospore-producing plant pathogen were evaluated. The strain Pseudomonas koreensis 2.74 was added as washed cells, in its spent KB broth or in a minimal medium adapted from the nutrient solution, and compared with control treatments. A significant reduction in disease with up to 50% was achieved when a high concentration of washed cells was added weekly to the plant cultivation system. The disease suppression obtained through addition of washed cells equalled the effect achieved when the purified biosurfactant was used. Phytotoxicity was observed when the spent broth was included in the treatment.
Insect and mite control by sufficient drying and cooling of commodities would satisfy growing market desire for pesticide-free storage and help control increased insect resistance, particularly to phosphine. The response of insects and mites to such conditions, as opposed to those specifically targeted for disinfestation, is reviewed. The responses to temperatures at various humidities within the range 9–55 °C are examined which include those that induce individual mortality, those at the threshold for population growth, and those where rates of growth are slow. Drying is examined mainly in terms of an enhancement to the detrimental effects of temperature. A 10 °C range in minimum threshold temperature for population growth was found among the insect and mite species examined. A substantial level of protection was seen at temperatures just above these thresholds. At conditions roughly 6 °C below the threshold for population growth, >99% mortality of major coleopteran species is possible after 9 months at 45% r.h. Insect mortality at moderately elevated grain temperatures (35–55 °C) is examined as an opportunity to disinfest grain during drying. Several coleopteran and psocopteran species were found to suffer at least 99% mortality at 50 °C after 2.5 h. The extent of variation among species is discussed in terms of targeting particular susceptibilities to moderately low or high temperatures at low humidities as an alternative to chemical treatments.
A solution of heat-denatured whey proteins was prepared by heating 10 wt.% whey protein isolate at pH 7.0 to 80°C for 10 min in the absence of salt. This treatment caused the globular protein molecules to partially unfold and aggregate. When the heat-denatured whey protein solution was cooled to room temperature and mixed with 200 mM NaCl it formed a gel. The influence of sucrose (0 to 10 wt.%) in the protein solutions prior to NaCl addition on the gelation rate was investigated. At relatively low concentrations (0–8 wt.%) sucrose decreased the gelation rate, presumably because sucrose increased the aqueous phase viscosity. At higher concentrations (> 8 wt.%) sucrose increased the gelation rate, probably because it decreased the thermodynamic affinity of the globular proteins for the aqueous solution, which increased the attraction between proteins. This data has important implications for the application of cold-setting whey protein ingredients in sweetened food products such as deserts and beverages.
Response surface methodology (RSM) was employed to optimize the cultivation conditions of Bacillus subtilis S3 for the enhancement of iturin A, a lipopeptide antibiotic used as biological pesticide, production in solid-state fermentation (SSF). The statistic experimental model predicted a maximum iturin production of 11.435mg/g-wet solid material. Verification of the calculated maximum was done with experiments that were performed in the culture media representing the optimum combination found, and the iturin A production of 11.447mg/g-wet solid material (average of three repeats) was obtained when B. subtilis S3 was cultivated at 25°C for 5 days in solid fermentation containing high gluten flour 10g and rice bran 50g in addition to glucose 1.15%, KH2PO4 1.27mM, MgSO4 5.08mM, peanut oil 1.01%, inoculum 19.49% and water content 44.97%. The iturin A production by B. subtilis S3 was increased significantly by 23%, from 9.26mg/g-wet solid material to 11.447mg/g-wet solid material when the strain was cultivated in the optimal medium developed by surface response methodology, as compared to medium conventionally developed by one-factor-at-a-time. The yield of iturin A (11.447mg/g-wet solid material, with 45% moisture content) produced by B. subtilis S3 reported in this study is the highest reported to date for B. subtilis species in SSF. In addition, the use of rice bran as a substrate in solid-state fermentation for iturin A production by B. subtilis is unique.
The biological activities of two species of bacteria isolated from soil of cotton fields identified as Bacillus subtilis strain NRC313 (BS NRC313) and Bacillus thuringiensis strain NRC335 (BT NRC335) were evaluated against the third larval instar of the cotton leafworm, Spodoptera littoralis (Boisd.). The different entomopathogenic bacteria of BS NRC313and BT NRC335 contained 10 × 108 cell/ml, and caused mortality of 100 and 97.3% for the above mentioned strains, respectively. Concentrations of 2.5 × 108 to 10 × 108 cell/ml of strains BS NRC313 and BT NRC335 were applied to the larvae: LC50 were 3.3 × 108 and 3.9 × 108 cell/ml respectively. The influence of exposure to toxin concentrations manifested in terms of decreasing the adult emergence and prolongation of the generation period. The percentage of larvae that survived and succeeded to pupate increased by decreasing the concentration. The longevity of adult emergence that resulted from larvae treated with Bacillus subtilis were 6.0 ± 0.51 and 9.0 ± 0.63 days at 5 × 108 and 2.5 × 108 cell/ml, respectively compared with 9.8 ± 0.47 in control. The results indicated that Bacillus subtilis was more potent than Bacillus thuringiensis. Field applications of B. thuringiensis, B. subtilis and Reldan achieved 55.6, 67.4 and 89.4% reduction of the cotton leafworm larvae Spodoptera littoralis in clover plants under field conditions.
The fine structure of the mid-gut epithelium and regenerative cells of larvae of a moth (Ephestia kühniella) is described. Particular attention is paid to the absorptive and goblet cells and their lateral junctions; these features are discussed in terms of the digestive and regulatory functions of the epithelium. One digestive pathway has been investigated with the aid of ingested ferritin; intake of this marker by endocytosis and the evident involvement of Golgi vesicles in the transformation of endocytic vesicles into multivesicular bodies, together with the fate of the latter, are discussed in terms of the digestive function of this part of the alimentary tract and of the lysosome concept.
Biosurfactants or microbial surfactants are surface-active biomolecules that are produced by a variety of microorganisms. Biosurfactants have gained importance in the fields of enhanced oil recovery, environmental bioremediation, food processing and pharmaceuticals owing to their unique properties such as higher biodegradability and lower toxicity. Interest in the production of biosurfactants has steadily increased during the past decade. However, large-scale production of these molecules has not been realized because of low yields in production processes and high recovery and purification costs. This article describes some practical approaches that have been adopted to make the biosurfactant production process economically attractive. These include the use of cheaper raw materials, optimized and efficient bioprocesses and overproducing mutant and recombinant strains for obtaining maximum productivity. Here, we discuss the role and applications of biosurfactants focusing mainly on medicinal and therapeutic perspectives. With these specialized and cost-effective applications in biomedicine, we can look forward to biosurfactants as the molecules of the future.
KEYWORDS Solid substrate fermentation; solid matrix; fungi; bioreactor design. ABSTRACT Solid substrate fermentation (SSF) has been usually exploited for the production of value-added products (antibiotics, alkaloids, plant growth factors, etc), biofuel, enzymes, organic acids, aroma compounds and also for bioremediation of harzardous compounds, biological detoxification of agro-industrial residues, nutritional enrichment, biopulping, biopharmaceutical products, etc. This technology has gained renewed attention from industry because it has become a more attractive alternative to liquid fermentation for many productions. Thus, SSF was found to produce a more stable product, with less energy requirements, in smaller fermenters and smaller volumes of polluting effluents. This paper aims to present an overview of the main characteristics and applications of SSF, as well as their advantages and disadvantages compared to submerged liquid fermentation (SLF). The effect of the main variables in SSF processes and important aspects related to design of SSF bioreactors are also discussed.
Production of a lipopeptide antibiotic, surfactin, in solid state fermentation (SSF) on soybean curd residue, Okara, as a solid substrate was carried out using Bacillus subtilis MI113 with a recombinant plasmid pC112, which contains lpa-14, a gene related to surfactin production cloned at our laboratory from a wild-type surfactin producer, B. subtilis RB14. The optimal moisture content and temperature for the production of surfactin were 82% and 37°C, respectively. The amount of surfactin produced by MI113 (pC112) was as high as 2.0 g/kg wet weight, which was eight times as high as that of the original B. subtilis RB14 at the optimal temperature for surfactin production, 30°C. Although the stability of the plasmid showed a similar pattern in both SSF and submerged fermentation (SMF), production of surfactin in SSF was 4–5 times more efficient than in SMF. © 1995 John Wiley & Sons, Inc.
Production of a family of lipopeptide antibiotic, iturin byB. subtilis NB22, in solid state fermentation (SSF) of wheat bran (WB) was investigated. The amount of iturin produced per unit weight of wet substrate was 5–6 times more than that in the submerged fermentation (SMF). SSF enabled to produce a homologue of iturin with strong antibiotic activity in a larger fraction compared with the SMF.
Twenty three strains of Bacillus spp. screened from 205 Bacillus spp. isolated from soil, showed antagonistic activities in vitro towards the Penicillium digitatum pathogen, a cause of citrus fruit rot disease. Culture supernatants from nine strains caused >80% inhibition of P. digitatum growth when they were serially diluted to 1:32. Volatile compounds produced by these strains also caused 30–70% inhibition of fungal growth. An ethanol extract from a Bacillus subtilis 155 cell-free supernatant referred to as secondary metabolites (SMs) produced the best inhibitory effect on mycelial growth and spore germination of the fungus with EC50 values of 77.26 and 82.10 μgm L−1, respectively. Inhibitory compounds, separated from the SMs by preparative thin-layer chromatography (CHCl3/MeOH/H2O: 65/25/4, v/v/v), had Rf values of 0.14, 0.28, 0.31, 0.49, and 0.64 with EC50 values of 95.73, 14.07, 15.19, 108.59, and 99.98 μg mL−1, respectively. Protein precipitated with 80% saturated ammonium sulphate, from the culture supernatant, had an EC50 of 288 μg mL−1. After native polyacrylamide gel electrophoresis of this protein the antifungal protein activity was detected only in the lowest band. Inoculation of a suspension of P. digitatum conidia (104 conidia mL−1) onto wounded citrus fruit induced disease symptoms at day 3 and decay at day 5. Inoculation with 20 μL of a 108 CFU mL−1B. subtilis endospore suspension 24 h prior to fungal spore inoculation decreased disease incidences by 86.7%, and disease symptoms were delayed by 6 days and decay symptoms to day 9. Addition of the SMs (10 mg mL−1), simultaneously with the fungus decreased disease incidence by 72.5%, delayed disease symptoms up to 5 days after inoculation, and no sign of decay was observed up to 9 days. The average lesion diameters observed from treatments with bacterial endospores, SMs and a control fungicide, imazalil were significantly different from the size of the wounds in the control set treated only with fungal conidia. B. subtilis 155 and its antibiotics are considered to be potent biological control agents to suppress growth of P. digitatum in the postharvest protection of citrus.
