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Bioethanol production from carob pods by solid-state fermentation with Zymomonas mobilis
Abstract
The production of bioethanol from carob pod particles by solid-state fermentation (SSF) using Zymomonas mobilis was investigated. Wheat bran particles were mixed with carob pods as filler and support for bacterial growth. The Plackett–Burman (P–B) experimental design was used for initial screening of various factors affecting the process including temperature, initial moisture content, carob particle size, wheat bran particle size, pH, initial cell concentration, peptone and yeast extract concentration and fermentation time. Then the five most effective factors (temperature, carob particle size, peptone concentration, initial cell concentration and fermentation time) were optimised for maximum ethanol-concentration production by response surface methodology (RSM). The maximum of 0.30 g ethanol g−1 initial sugar was produced at 31 °C with initial moisture content of 80% (w/w), carob particle size 1 mm, peptone concentration 0.7% (w/w), initial cell concentration 6.74 × 108 cells g−1 carob and fermentation time 43 h.
... Nowadays, the primary uses of the carob's pulp are as animal feed [10] or production of bioethanol [11]. For humans, carob's pulp have been used primarily in traditional foods such as confectioneries, beverages, bread or pasta in a few countries in the Mediterranean region because of their low price [4][5][6][7][8][9]. ...
... Each treatment was evaluated for aromatics, basic taste and feeling factors attributes. Preparation protocol was similar to Rababah et al. [11] with slight modifications: 8 h orientation sessions were necessary for the panellists to develop the test methodology necessary to describe the characteristics of the sensory attributes of carob drinks samples. Panellists underwent an orientation session using carob drink to improve their reproducibility and accuracy. ...
... Moreover, Elfazazi et al. [5] reported that physicochemical and biochemical analysis of carob tree in Morocco (Beni Mellal region) showed significant differences depending on the origins. These differences can be related to edaphic factors, crop site, age of the trees and season [5][6][7][8][9][10][11][12][13]. ...
The chemical, functional and sensory properties of Moroccan carob drink were evaluated. The carob pods were collected from Beni Mellal region in Morocco. The carob drink was processed from the pulp referring to an improved local process. The ash, moisture contents, pH, Brix, total acidity, water activity and pectin content were determined. Bio actives contents, total phenolics, flavonoids and condensed tannins were evaluated. Carob drink is a slightly acidic (total titratable acidity = 1.6 g CAE/ L and pH = 5) with high water activity value (a w = 0.87). Carob drink of Dir Lekssiba had significantly higher contents of total phenolic (843 lg GAE/mL), condensed tannin (28.1 mg TAE/100 mL) and flavonoids contents (55.3 mg RE/mL) than drink of Ait Oum Elbakht respectively 710 lg GAE/mL, 20.7 mg TAE/100 mL and 34.2 mg RE/mL. Sensory analysis showed that the carob drink is generally a sweet and astringent product with aromatic notes especially caramel and metallic. The aroma and sweet intensity is more pronounced for Ait Oum Elbakht drink. However, astringency is more pronounced for Dir Lekssiba drink.
... En conclusion, la fermentation solide apparaît comme une alternative possible pour la production d'éthanol à partir de déchets solides de caroube, ce qui ouvre la possibilité d'une utilisation directe du déchet solide. Enfin, la production de bioéthanol à partir de caroube par Zymomonas mobilis a été étudiée par Mazaheri et al. (2012). Les particules de son de blé ont été mélangées avec des gousses de caroube comme support pour la croissance bactérienne. ...
... For comparison, purpose, SSF process was tested on carob pods using Zymomonas mobilis, leading to a maximum ethanol yield of 0.30 g ethanol/g initial sugar (Mazaheri et al., 2012), but also on mahula flowers , sweet sorghum (Yu et al., 2008), and arrowroot, grape and sugar beet pomaces (Rodríguez et al., 2010). In parallel, a careful review of the literature also indicates that carob pulp can be used as a feedstock for ethanol submerged fermentation with free or immobilized cells. ...
... studied the production of ethanol from mahula flowers: maximum ethanol concentration (225.0±4.0 g/kg flower), ethanol productivity (3.13 g/kg flower/h), and ethanol yield (58.4 g/100 g consumed sugar) obtained after 72-hour fermentation. Mazaheri et al. (2012) investigated the production of ethanol from carob by solid fermentation using Zymomonas mobilis; they reported 43 g/ 100 g yield in 43-hour fermentation time, and the productivity of the SSF process was 3.72 g/(kg carob)/h. Similarly, Sree et al. (1999) reported highest ethanol concentration of 50 g/kg substrate (sweet sorghum and sweet potato) in SSF using S. cerevisiae. ...
Cette thèse de doctorat porte sur la valorisation du déchet solide issu de la préparation de la mélasse de caroube libanaise pour la production de bioénergie et de molécules à valeur ajoutée. L’analyse de la composition de ce déchet a montré qu’il contient 45 % (g/g) de sucres, substrats exploitables pour la fermentation alcoolique ou lactique, la production de biohydrogène, ou comme source de carbone pour la croissance d’une algue dans un procédé de phycoremédiation (traitement des eaux par les algues) pour l’élimination de micropolluants pharmaceutiques. Les résultats obtenus ont montré que la fermentation alcoolique en phase liquide à partir d’extraits de déchet de caroube peut conduire à des rendements élevés en bioéthanol sous réserve d’enrichir le milieu de culture par les éléments nécessaires pour la croissance de la levure Saccharomyces cerevisiae (en particulier l’azote), tandis qu’il est possible de produire directement le bioéthanol sur le déchet par fermentation en milieu solide sous réserve de contrôler précisément l’humidité. Nous avons également démontré que la fermentation lactique par immobilisation de Lactobacillus rhamnosus sur des billes d’alginate constitue une alternative possible au bioéthanol pour les sucres extraits du déchet. Cependant, un enrichissement du milieu de culture, ainsi que l’utilisation d’une invertase en prétraitement sont nécessaires afin de maximiser le rendement et la productivité de l’acide lactique. L’immobilisation des microorganismes a permis de réutiliser les mêmes billes d’alginate au cours de cinq cycles successifs de production. Une autre alternative potentielle aux voies précédentes est la fermentation sombre pour la production de biohydrogène directement à partir du déchet. Si des rendements intéressants ont été atteints, il faut noter que comme précédemment dans le cas de la fermentation solide du déchet, une forte dépendance aux conditions initiales de broyage a été mise en évidence ; de plus, à la carence en azote qui obligeait à supplémenter les milieux en fermentation en phase liquide s’ajoutent des besoins en fer. Enfin, l’utilisation du déchet comme substrat carboné dans un procédé de phycoremédiation avec l’algue Ankistrodesmus braunii a montré que l’élimination de 90% du diclofénac initial pouvait être atteinte en conditions de mixotrophie, même si seulement un tiers du diclofénac éliminé est effectivement métabolisé par l’algue.
... In addition, Z. mobilis as a bacterium has simpler and cheaper culture media than that of the S. cerevisiae. In this regard, various studies have shown the successful use of Z. mobilis for bioethanol production from various feedstocks [15][16][17][18][19][20]. In the study of bioethanol production from agricultural wastes, Braide et al. reported the ethanol yield percentage of 5.17% from PP by Z. mobilis and 5.51% by S. cerevisiae, indicating the good ability of Z. mobilis for bioethanol production from PP [19]. ...
... Since there were few previously published study on fermentation of PP by Z. mobilis, we evaluated and optimized the effective parameters in ethanol fermentation process in this section using RSM central composite design. Based on the previous studies [15,16,[18][19][20]23] on Z. mobilis as well as some preliminary experiments, we identified five important factors and checked their high and low levels for optimization process by RSM. The factors were initial sugar concentration, bacterial dry cell weight, peptone and yeast extract weight, and fermentation time. ...
... In molasses fermentation with 0.02 g/l Z. mobilis in the time range of 24-48 h, the temperature of 30°C and pH within the range of 5.0-7.0 were reported as optimum conditions [18]. Similarly, in solid-state fermentation of carob pod by Z. mobilis, the optimum temperature of 31°C, pH 5.1, and 0.7 g of meat peptone (7 g/l) were also reported as the optimum conditions [16]. After identifying the effective factors and their ranges, fifty experiments were designed with the amount of produced ethanol as response measured for each experiment (Table 1). ...
In this study, Zymomonas mobilis was used to produce bioethanol from potato peel (PP) wastes. For this purpose, enzymatic hydrolysis was first performed on potato peel to release the fermentable sugars. Then, the effect of enzyme dosages and solid loading was investigated on the hydrolysis process. Following the hydrolysis step, to evaluate the ability of Z. mobilis in bioethanol production from PP, the effects of five important factors (initial sugar concentration, bacterial dry weight, peptone and yeast extract weights, and fermentation time) were studied, after which the factors were optimized using response surface methodology (RSM) experimental design. It was observed that a maximum of 88.2 g/l reducing sugar was produced using 50 U α-amylase and 12 U amyloglucosidase with 20%PP solid loading. The optimized conditions for fermentation step were as follows: 61.3 g/l initial sugar, 0.024 g bacterial dry cell, 0.35 g meat peptone, 0.35 g yeast extract, and 31-h fermentation time. The maximum ethanol concentration of 23.3 ± 0.015 g/l was produced under the optimum conditions. Time courses of ethanol production and sugar consumption were also studied, revealing consumption of 78.9% of initial sugars under optimum conditions.
... The good potential of Z. mobilis for converting the carob sugars to ethanol and the advantages of the SSF process make the SSF of carob pod by Z. mobilis an interesting process. Recently, a maximum of 0.3 g ethanol per g initial sugar was produced by SSF of carob particles and wheat bran using Z. mobilis [101]. Mazaheri et al. reported that Z. mobilis could not grow when carob alone was used as a solid substrate. ...
... This may be attributed to the high sugar content of carob pods, especially in the liquid film-coated carob particles, which inhibits bacterial growth and ethanol production. Therefore, a mixture of carob pods and wheat bran (as a support for bacterial growth) was used as solid substrate [101]. They also performed this process in a packed bed column, and realized that the entrapped CO 2 in the bed inhibits the production of ethanol. ...
The ever-increasing population of the world, extended urbanization/industrialization in developing countries, improvements in quality of life, and increasing oil prices have accelerated the need for sustainable energy sources. Among different alternatives, biofuels in general and bioethanol in particular are promising sustainable and eco-friendly energy sources. However, cheap feedstocks and new production technologies are required to make bioethanol economically comparable with traditional fossil fuels. An efficient, cost-effective, and promising technology is solid-state fermentation (SSF) in which microorganisms grow on the surface of solid materials in the absence of free water resulting in elimination of sugar extraction process and less wastewater production, which in turn yields lower distillation and purification costs. Furthermore, SSF is a well-established technology for production of different enzymes. This potential of SSF makes it an appropriate process for enzymatic pretreatment and hydrolysis of substrates and subsequent bioethanol production. This review gives an overview of the applications of SSF in every step of bioethanol production; compares its efficiency and feasibility with the submerged fermentation process; and for brevity of exposition, highlights the great promise of this technology for sustainable and cost-effective bioethanol production.
... For comparison purpose, SSF process was tested on carob pods using Zymomonas mobilis, leading to a maximum ethanol yield of 0.30 g ethanol/g initial sugar (Mazaheri et al., 2012), but also on mahula f owers (Mohanty et al., 2008), sweet sorghum (Yu and Tan, 2008), and arrowroot, grape and sugar beet pomaces (Rodríguez et al., 2010). In parallel, a careful review of the literature also indicates that carob pulp can be used as a feedstock for ethanol submerged fermentation with free or immobilized cells. ...
... Mohanty et al. (2008) studied the production of ethanol from mahula f owers: maximum ethanol concentration (225.0 ±4.0 g/kg f ower), ethanol productivity (3.13 g/kg f ower/h), and ethanol yield (58.4 g/100 g consumed sugar) obtained after 72-h fermentation. Mazaheri et al. (2012) investigated the production of ethanol from carob by solid fermentation using Zymomonas mobilis; they reported 43 g/ 100 g yield in 43-h fermentation time, and the productivity of the SSF process was 3.72 g/(kg carob)/h. Similarly, Sree et al. (1999) reported highest ethanol concentration of 50 g/kg substrate (sweet sorghum and sweet potato) in SSF using S. cerevisiae. ...
The aim of this work was to develop a strategy for second-generation ethanol production from carob solid waste issued from Lebanese food industry. The pros and cons of submerged (SF) and solid-state fermentations (SSF) using S. cerevisiae on ethanol yield and productivity were compared, including the respective roles of upstream and downstream processes, such as the size reduction, or sugar and ethanol recovery processes. The design of experiments methodology was applied. Experimental results demonstrated that SSF applied to cut carob waste from carob syrup preparation was simpler to operate and more cost-effective, maintained yield and productivity (0.458 g ethanol/g consumed sugar and 4.3 g/(kg waste)/h) in comparison to SF (0.450 g ethanol/g consumed sugar and 5.7 g/(kg waste)/h), and was able to achieve ethanol production up to 155 g/(kg waste) at low water demand, while SF reached only 78 g/(kg waste) due to the limitations of the sugar extraction pretreatment.
... Three main steps are required to obtain 2G bioethanol from lignocellulosic biomass, namely, pretreatment, enzymatic saccharification, and fermentation and distillation [2,11,13,14]. Many pretreatment methods of lignocellulosic biomass are listed in the literature, including physical pretreatment (grinding, milling, microwave, and extrusion), chemical pretreatment (hydrothermal-aqua Solv [1], alkali [1,2], acid, organosolv, ozonolysis and ionic liquid), physicochemical pretreatment (steam explosion, liquid hot water, ammonia fiber explosion AFEX, wet-oxidation, and CO 2 explosion), and biological pretreatment (delignification of lignocellulosic substrate by Basidiomycota fungi) [15]. ...
... Thus, the ethanol conversion efficiency is 1.58% and its volumetric yield 70% which is higher than the ethanol conversion efficiency obtained from hydrothermal pretreated and enzymatic hydrolysate lucerne, ranging from 41.7% and 62.8% [48]. This amount is also more important than those reported for the alkali pretreated sugarcane bagasse fermentation, which is about 40.84% (of theoretical yield) achieved after 24 h using Saccharomyces cerevisiae [2] and for other lignocellulosic feedstocks, that is, dried carob pod particles fermented with Zymomonas mobilis (43%) [14] and microwave hydrothermal pretreated (900 W for 2 min) sago pith waste fermented with Saccharomyces cerevisiae (15.6%) [49]. However, the hydrothermal pretreated LC fibers ethanol conversion yield is slightly lower than the ethanol efficiency of wheat bran's starch fermented with S. cerevisiae yeast (81%-89%) [3]. ...
This paper opens up a new issue dealing with Luffa cylindrica (LC) lignocellulosic biomass recovery in order to produce 2G bioethanol. LC fibers are composed of three principal fractions, namely, α -cellulose (45.80% ± 1.3), hemicelluloses (20.76% ± 0.3), and lignins (13.15% ± 0.6). The optimization of LC fibers hydrothermal and diluted acid pretreatments duration and temperature were achieved through the cubic central composite experimental design CCD. The pretreatments optimization was monitored via the determination of reducing sugars. Then, the 2G bioethanol process feasibility was tested by means of three successive steps, namely, LC fibers hydrothermal pretreatment performed at 96°C during 54 minutes, enzymatic saccharification carried out by means of a commercial enzyme AP2, and the alcoholic fermentation fulfilled with Saccharomyces cerevisiae . LC fibers hydrothermal pretreatment liberated 33.55 g/kg of reducing sugars. Enzymatic hydrolysis allowed achieving 59.4 g/kg of reducing sugars. The conversion yield of reducing sugar to ethanol was 88.66%. After the distillation step, concentration of ethanol was 1.58% with a volumetric yield about 70%.
... The optimization of fermentation conditions is also an important step in the development of economically feasible bioprocesses [6]. Statistical optimization techniques have been widely used for process optimization in the production of biological metabolites [13][14][15][16][17]. Conventionally, many bioprocesses are optimized by using the one factor-at-a-time method, which involves changing one independent variable (nutrient, temperature, aeration rate) while fixing the other parameters at a certain level. ...
... If the variances tend to be the same, the ratio will be close to 1 and it is likely that the model or any of the factors will not have a significant effect on the responses. Model F-values are calculated as the model variance divided by the error variance [15]. The model F values of 32.40, 48.77, and 45.41 for product yield, biomass, and schizophyllan, respectively, implied that the predicted models were significant. ...
This study demonstrates the efficient utilization of low-cost agricultural substrates, particularly date syrup, by Schizophyllum commune ATCC 38548 for schizophyllan production. Initially, one factor-at-a-time method was used to find the best carbon and nitrogen sources for schizophyllan production. Subsequently, response surface methodology was employed to optimize the level of culture medium components to maximize substrate conversion yield and schizophyllan production in submerged culture. Maximum product yield (0.12g schizophyllan/g date syrup) and schizophyllan production (8.5g/l) were obtained at concentrations of date syrup and corn steep liquor, inoculum size and agitation rate at 7.02%w/v, 0.10%w/v, 7.68%v/v and 181rpm, respectively. Sugar composition analysis, FTIR, NMR and molar mass determination revealed the purity and molecular properties of recovered schizophyllan produced from date syrup as glycosidic linkage analysis showed three main schizophyllan characteristic peaks arising from the 3-linked, 3,6-linked and terminal glucose residues. Finally, process economic analysis suggested that use of date syrup and corn steep liquor as nutrients would result in approximately 6-fold reduction in cost of raw materials for schizophyllan production as compared to conventional carbon and nitrogen sources such as sucrose and malt extract.
... [189] Carob and its waste products can be utilized for bioethanol production because of their high sugar and mineral content. [190] Mazaheri et al. [191] reported bioethanol production from Zymomonas mobilis by using RSM and wheat bran mixed in carob pod as media for bacterial growth. The maximum recorded production was 0.30 g ethanol/g of initial sugar. ...
Carob (Ceratonia siliqua) is one of Asia and Africa's popular nutritional and medicinal crops. This unique plant has an outstanding functional properties and nutritional profile. Carob has high sugar content, drought resistance and is very economical. Carob fruit consists of pulp and seed that are rich sources of different bioactive components. Carob has wide applications in various industries (food, pharmaceuticals and cosmetics) as an anti-oxidant, thickener, stabilizer, lactic acid production and emulsions. The trend of moving towards natural products further highlights the use of carob in different fields due to its excellent nutritional and therapeutic profile. Carob bean gum is widely used in the food industry. The current review has highlighted the nutritional composition, bioactive profile, functional properties, and recent findings on the subject.
... Due to its contribution to the maintenance of soil fertility, carob improves the establishment of other species, and is particularly suitable for the reforestation in the harsh climatic conditions and poor soils of some Mediterranean basin areas (pioneer and productive species). In these marginal areas, as a cultivated species, carob is able to provide environmentally and economically valuable productions: carob bean gum, fodder for ruminants and non-ruminants, sugar syrups, cocoa substitutes, bioethanol, and secondary metabolites (Gubbuk et al. 2010;Mazaheri et al. 2012;Amessis-Ouchemoukh et al. 2017;Benković et al. 2017). ...
Carob (Ceratonia siliqua L.) is a relevant element of the Mediterranean spontaneous vegetation. Moreover, it is useful in reforestation, and it is currently re-valued for sustainable agriculture in dryland areas. However, the difficulties tied to carob propagation (mainly seed dormancy) hamper its large-scale cultivation. In this paper, the effects of four seed treatments (no treatment [control], soaking at 70 °C and 90 °C in water, or in 96% sulphuric acid) on five carob genotypes germination were studied. As compared to the very low germination of untreated seeds (0–13% germination), sulphuric acid (93–100% germination) and 90 °C water soaking (from 72 to > 90% germination in four out the five genotypes) were effective in promoting germination. Soaking at 90 °C resulted in the leaching of a higher amount of total polyphenols from the genotypes seed coat as compared to soaking at 70 °C. A significant correlation (0.75**) was ascertained between polyphenol leaching of the different genotypes and germination. These results suggest that dormancy in this species is not primarily associated with seed coat hardness, as it is generally thought, but also with the release of polyphenols. Polyphenols determination of the dormant and the few non-dormant seeds of the different genotypes also seem to confirm this hypothesis since these last showed an almost halved total polyphenols content (on average 17.0) as compared to dormant ones (34.8 mg g−1 of seed FW). Further studies may determine the polyphenols involved, but also assess new, easier to carry out, seed treatments. The important role of the galactomannans on seed germination of carob is also discussed. Finally, similar studies may enhance the knowledge of dormancy processes in other Fabaceae species whose germination is positively affected by hot water treatments.
... After the saccharification step, the fermentation step is performed to convert sugars to ethanol, in which yeasts such as Saccharomyces cerevisiae [8,11] and Pichia stipitis [9] or bacteria such as Zymomonas mobilis [14,15] are used. But a more appropriate method, instead of separate saccharification and fermentation, is using simultaneous saccharification and fermentation (SSF), in which the saccharification of cellulose into fermentable sugars is performed by the enzyme and the immediate conversion of sugars to ethanol is performed by the yeast simultaneously [16,17]. ...
Due to the high production of pomegranate peel waste in the world, and its good lignocellulosic content, this substance can be a good source for fuel bioethanol production. In this study, the simultaneous saccharification and fermentation (SSF) process was investigated and optimized for bioethanol production from pomegranate peel (PP). After hydrothermal pretreatment on pomegranate peel and separation of pectin and phenolic compounds, the SSF process was performed using cellulase and Saccharomyces cerevisiae. The effect of the four parameters of pH, temperature, solid loading, and enzyme dosage on the bioethanol production in the SSF process was investigated and optimized using the response surface methodology (RSM). Optimal process conditions were determined as follows: pH 5.65, temperature 40.3 °C, solid loading 12.8% w/v, and enzyme dosage 32.3U, under which the maximum amount of ethanol produced was 12.9 g/l. Furthermore, 90.4% of initial sugar was consumed by the yeast during the process, and the yield of ethanol production was 48.5%, which corresponds to 95.09% of the theoretical yield. The trend of changes in ethanol and sugar concentrations during the process time was also studied.
... Carob pulp is rich in total sugar content (31-50%) that can easily be water extracted to be used for syrups production (El Batal et al. 2011). It can also be exploited for the production of bioethanol (Mazaheri et al. 2012) and natural antioxidants (Roseiro et al. 2013;Benchikh et al. 2014;Amessis-Ouchemoukh et al. 2017). Due to these economical and ecological benefits, many countries have promoted the cultivation and exploitation of this valuable genetic resource (Battle and Tous 1997;Lozzi et al. 2015). ...
La présente invention fourni un nouveau milieu nutritif, développé pour la première fois pour la micropropagation in vitro de caroubier. Le milieu nutritif développé contient les éléments essentiels pour la croissance des vitroplants de caroubier àdes concentrations appropriées à cette espèce. La présente invention fourni également un procédé simple, rapide et économique pour la micropropagation de caroubier en utilisant le milieu de culture liquide et la technique d'enracinement ex vitro. Ce procédé constitue un outil important qui pourra faciliter la multiplication en masse de vitroplants de qualité chez le caroubier afin de répondre à la demande mondiale croissante en matière de cette espèce.
... In this case, Z. mobilis was genetically improved for pentose utilization to increase the final ethanol concentration up to 86% of theoretical yield (Su et al. 2013). Advanced solid stage fermentation (ASSF) has been used for ethanol production by Z. mobilis using solid carob pods and wheat bran mixture to produce an ethanol yield of 0.30 g/g, and corn cob has been used to produce 60.5 g/L of ethanol under the submerged fermentation method (Mazaheri et al. 2012;Su et al. 2013). Recently, consolidated bioprocessing (CBP) has emerged as a promising technology for cost-competitive biofuel production by combining cellulase production, lignocellulosic hydrolysis and sugar fermentation in a one step process. ...
Zymomonas mobilis is an ethanologenic microbe that has a demonstrated potential for use in lignocellulosic biorefineries for bioethanol production. Z. mobilis exhibits a number of desirable characteristics for use as an ethanologenic microbe, with capabilities for metabolic engineering and bioprocess modification. Many advanced genetic tools, including mutation techniques, screening methods and genome editing have been successively performed to improve various Z. mobilis strains as potential consolidated ethanologenic microbes. Many bioprocess strategies have also been applied to this organism for bioethanol production. Z. mobilis biofilm reactors have been modified with various benefits, including high bacterial populations, less fermentation times, high productivity, high cell stability, resistance to the high concentration of substrates and toxicity, and higher product recovery. We suggest that Z. mobilis biofilm reactors could be used in bioethanol production using lignocellulosic substrates under batch, continuous and repeated batch processes.
... Besides, in the fabrication of bioethanol from carob extract, several different reactor designs such as suspendedcell stirred-tank reactor (SCSTR), 25 immobilized cell stirred tank bioreactor, 28 plastic composite support-biofilm reactor, 2,20,22 solid-state bioreactor, 46 etc. and different fermentation modes including batch, fed-batch, repeatedbatch, and continuous have been utilized. Among them, batch SCSTR is one of the conventional reactors and commonly applied for fabrication of high value-added products (especially ethanol) from renewable resources. ...
In this study, various functions were evaluated and utilized to forecast observed values and kinetic parameters of the batch ethanol fabrication from carob extract in the suspended‐cell stirred tank reactor (SCSTR). The best model was detected with the model comparison parameters (root‐mean‐square‐error [RMSE], mean‐absolute‐error [MAE], and R 2 ). The results indicated that the model Stannard (ST) successfully predicted biomass production data (RMSE = 0.26 g L⁻¹, MAE = 0.18 g L⁻¹, and R 2 = 0.9910), ethanol fabrication data (RMSE = 2.44 g L⁻¹, MAE = 1.88 g L⁻¹, and R 2 = 0.9809), and sugar depletion data (RMSE = 2.82 g L⁻¹, MAE = 2.17 g L⁻¹ and R 2 = 0.9938). Nevertheless, the lowest value of the objective function (Φ ‐factor) was also yielded as 0.041 using the model ST. Additionally, in the estimation of the kinetic data, the model ST also gave well‐directed results. Besides, when an independent set of the observed values was utilized to confirm the mathematical functions, the satisfactory consequences were achieved in terms of both the experimental and kinetic values. Consequently, the model ST can work as a universal function in predicting observed values and kinetics of batch ethanol generation from carob extract in an SCSTR.
... Recently, researchers have focused on the valorization of carob pods since they are an excellent source of sugar (Boublenza et al., 2017;Bulca, 2016;Mazaheri et al., 2012;Turhan, Bialka, Demirci, & Karhan, 2010)as well as bioactive compounds such as polyphenols which can be efficiently extracted by the mac- eration of chopped carob pods in hydroalcoholic base(Goulas, Stylos, Chatziathanasiadou, Mavromoustakos, & Tzakos, 1875;Nasar-Abbas et al., 2016;Rodríguez-Solana, Salgado, et al., 2019).Obtained liqueur is a desirable, aromatic drink with potential health benefits, and the amount of extracted compounds depends on the maceration conditions (Rodríguez-Solana, Coelho, et al., 2019;Rodríguez-Solana, Salgado, et al., 2019). The highest TPC values were found in the samples in which carob was macerated F I G U R E 3 Total phenols solid-liquid extraction (ratio 1:5-filled symbols and 1:10-open symbols) during carob pod maceration in 50% v/v hydroalcoholic base at room temperature exposed to sunlight (triangle) as well to darkness (rhomb) F I G U R E 4 Ternary diagrams present the proportion of individual sugars (glucose, fructose, and saccharose) in macerates obtained after a 12 week of carob pod macerationF I G U R E 5 Changes of the chromate characteristics of macerates during 12 weeks of carob pod maceration| 7 HANOUSEK ČIČA Et Al. in lower strength alcoholic base (50% v/v and 30% v/v) and ex- posed to darkness. ...
Abstract Carob liqueur is an alcoholic drink (minimum 15% v/v of ethanol and 100 g/L of sugar) typical for the Mediterranean countries. In the current work, carob macerate produced by maceration of carob pods in hydroalcoholic base at different maceration conditions was characterized for the first time based on its aroma compounds/profile, physicochemical parameters, and chromatic characteristics. The results confirm the migration process of bioactive compounds, aroma compounds, and sugars flowing from the carob pod to the hydroalcoholic base. Changes in ethanol concentration modify the physical properties of the solvent and influence the phenolic and aroma compounds extraction, color, and acidity of the obtained samples. The higher content of phenolic compounds was determinate in the samples obtained in the darkness. The amounts of phenols were in the range of some red fruit liqueurs or walnut liqueurs, and sugars (mostly sucrose) ranging between 96 and 107 g/L. Twenty‐six (out of total 94) aroma compounds were detected in all samples, of which 17 esters, 3 alcohols, 4 ketones, and 2 acids. Low molecular weight ethyl esters, ethyl hexanoate, ethyl 2‐methyl propanoate, ethyl octanoate, ethyl benzoate, ethyl butanoate, and ethyl cinnamate, were the most abundant. Carob pod maceration in 50% v/v hydroalcoholic base (1:5 solid to liquid ratio) in darkness at room temperature during 8 weeks can be recommended as optimal maceration conditions for production of the aromatic carob macerate with functional properties.
... The effect of carob and germ flour addition in gluten-free bakery products has been also reported [18][19][20], whereas the alternative uses of carob fruit are still examined. Carob seed residues were proposed as substrate or soil organic amendment [21], and the carob pods were recommended for the production of bioethanol after fermentation [22]. ...
Vaping is promoted as a healthier alternative to smoking over the recent years, and e-cigarette (EC) users are considered to affect air quality (and thus contribute to passive smoking) much less than tobacco cigarette (TC) smokers. Here we test this hypothesis, by comparing measurements of the size distributions of particles and the levels of Volatile Organic Compounds (VOCs) exhaled by both EC and TC users. A total of 26 individuals (16 EC users and 10 TC users) provided exhaled air samples that were analyzed using the same protocol. Our measurements show that the particle number concentration emitted by both EC and TC users are comparable, but the size distributions of the particles emitted by the former exhibit significantly higher variability compared to those from the latter. The burden of the VOCs was much higher in the exhaled air of TC smokers compared to that of EC users. Although some of the VOCs measured in the exhaled air of EC users were expected, as they are used directly in the e-liquids, the collected mixtures were highly variable (i.e., varying significantly from case to case) with only 8 compounds being common among all individuals participating in the study. In contrast, we identified 65 compounds among the TC smokers that were common among the participants. Toxic compounds (e.g., benzene, acetaldehyde, toluene, xylenes, styrene, phenol, naphthalene, etc.) were also present in the exhaled air of EC users. The high variabilities observed in the size distributions of the exhaled particles and the levels of VOCs from different EC users (i.e., due to different devices, operational settings and liquids) warrants for further research in order to fully understand the main- and side-stream effects of EC use in the human micro-environment. Despite that, the high particle emissions and the presence, even at trace levels, of toxic VOCs in the exhaled air of EC users that are reported in this study, suggests that ECs should not be considered as harmless substitutes of TCs.
... Carob pulp is rich in total sugar content (31-50%) that can easily be water extracted to be used for syrups production (El Batal et al. 2011). It can also be exploited for the production of bioethanol (Mazaheri et al. 2012) and natural antioxidants (Roseiro et al. 2013;Benchikh et al. 2014;Amessis-Ouchemoukh et al. 2017). Due to these economical and ecological benefits, many countries have promoted the cultivation and exploitation of this valuable genetic resource (Battle and Tous 1997;Lozzi et al. 2015). ...
A new basal culture medium was developed and tested using a rapid and efficient protocol of in vitro axillary shoot bud proliferation of Ceratonia siliqua L., an important Mediterranean Fabaceae plant species. In a first experiment, the new formulated ‘LA’ mineral composition significantly improved shoot growth and proliferation as compared with Murashige and Skoog medium (MS, 1962) in both solid and liquid culture media. However, the liquid culture system proved to be the most suitable for shoot induction, shoot length (about fourfold higher), and multiplication rate (about two-fold higher), the difference being significant. The measured growth and proliferation parameters were further improved when LA mineral composition was optimized, in a second experiment. The highest multiplication rate (6.3) was achieved during the second subculture using the optimized ‘LAC’ medium. Noticeably, hyperhydricity and shoot-tip necrosis symptoms were absent in both formulated LA and LAC compositions when using the liquid culture system. In vitro rooting in solid medium showed 41.7 to 46.3% response on a solid medium which was more suitable than the liquid culture system, the difference being significant. In contrast, pretreated microcuttings with 3 μM IBA (indole-3-butyric acid) were successfully rooted ex vitro, showing significantly higher response (91.7%), average root number (8.3), and root length (31.5 mm). The plantlets were successfully acclimatized showing more than 90% survivability and normal morphology. The present study is a first cost-effective protocol for carob micropropagation combining the use of the newly formulated LAC basal medium, a liquid culture system, and ex vitro rooting.
... LBG is mainly used as a thickening and stabilizing agent in food industry, as well as in cosmetics and pharmaceuticals. The production of bioethanol from carob pod by solid-state fermentation (SSF) and solid submerged fermentation using Zymomonas mobilis and Saccharomyces cerevisiae was also reported (Mazaheri et al. 2012;Saharkhiz et al. 2013). The extraction of sugars from the carob pods is a costly process; solid-state and solid submerged fermentations do not require sugar extraction; thus, these techniques are economical processes for bioethanol production. ...
The original publication of this paper contains an error.
... LBG is mainly used as a thickening and stabilizing agent in food industry, as well as in cosmetics and pharmaceuticals. The production of bioethanol from carob pod by solid-state fermentation (SSF) and solid submerged fermentation using Zymomonas mobilis and Saccharomyces cerevisiae was also reported (Mazaheri et al. 2012;Saharkhiz et al. 2013). The extraction of sugars from the carob pods is a costly process; solid-state and solid submerged fermentations do not require sugar extraction; thus, these techniques are economical processes for bioethanol production. ...
Biogenic volatile organic compounds (VOCs) contribute to the communication, growth, breeding, and defense of plant; their role in plant kingdom is vital. Carob tree is cultivated mainly in Middle East and eastern European countries (e.g., Spain, Italy, Greece, Cyprus) and lately in Australia, the USA, and South Africa. Therefore, it is examined as a case study for its volatile emissions in the environment. Apart from the VOCs emitted from carob flowers and fruit, carob is considered of great interest for the food industry (carob powder), not only for its health benefits but also due to its characteristic strong aroma, which can be maintained even after processing (roasting). Solid-phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) analyses of carob flowers, fruit, and powder (commercial samples) were performed and the detected VOCs are presented and discussed. The most prominent chemical classes emitted from carob fruit and powder appeared to be acids followed by esters and aldehydes/ketones, whereas from carob flowers the terpenoids. The strongest VOCs both in carob fruits and powder were propanoic acid, 2-methyl (isobutyric acid) and in flowers ethanol. The uniqueness of carob benefits is well known in the agriculture, pharmaceutical, cosmetic, and food sector and is closely related to the agro-economy and long history of eastern Mediterranean countries.
... Previous fermentation studies about carob pod extract showed that different microorganisms could be used as free or immobilized for bioethanol production. Some of the used microorganisms by researchers are Saccharomyces cerevisiae (Roukas, 1994;1996;Sánchez et al., 2010;Sánchez-Segado et al., 2012;Saharkhiz et al., 2013) , Saccharomyces cerevisiae (ATCC 36858) (Turhan et al., 2010b;Yatmaz et al., 2013;Germec et al., 2015;Germec et al., 2016) , Saccharomyces cerevisiae (F13A) (Lima-Costa et al., 2012;Raposo et al., 2017) , Saccharomyces cerevisiae (ATCC 7754) (Bahry et al., 2017) , and Zymomonas mobilis (PTCC 1718) (Vaheed et al., 2011;Mazaheri et al., 2012;Saharkhiz et al., 2013) . ...
Production of bioethanol is one of the important bioprocesses for the energy industry to provide inexpensive renewable resources all over the world. In this context, this research was organized for continuous ethanol fermentation from carob pod extract which is an inexpensive carbon source by free or immobilized S. cerevisiae cells. Continuous ethanol fermentations were performed with different HRT (from 4 to 20 h) and optimal HRT were 8 h for the free cell, and 6.67 h for immobilized cell, respectively. The highest volumetric ethanol productivities for free cell and immobilized cell fermentations were 3.12 g/L/h and 3.37 g/L/h at HRT of 5.71 h, respectively. All kinetic parameters clearly showed that both cell types can be used for ethanol fermentation, and immobilized S. cerevisiae ethanol fermentation can be operated at higher dilution rates independent of biomass than a free cell.
... The large availability of these materials, along with their low or even very low costs, makes them alternative sources of substrates that could be used for bacteria cultivations. Carob bean syrup was used as a culture medium to produce several bio-molecules such as ethanol (Roukas, 1994a, b;Turhan et al., 2008;Mazaheri et al., 2012;Germec et al., 2015), citric acid (Roukas, 1999) or lactic acid (Turhan et al., 2010). Enhancement attempts of Lactic acid production from carob bean syrup using fermentation process, such as the addition of sodium acetate and Tween 80 , and using invertase enzyme for hydrolyze of sucrose (Turhan et al., 2010), however, the addition of MRS components has not been characterised yet. ...
This study investigates the effect of the growth factors addition to carob pods syrup obtained by hot extraction at 5% for the production of lactic acid by Lactobacillus plantarum. Five fermentations were carried out by culture of Lb. plantarum in carob syrup. The fermentation control conducted in carob syrup (CS), fermentation characterized by addition of 10 g.L-1 of beef extract, culture enriched by 10 g.L-1 of beef extract and 5 g.L-1 of yeast extract, fermentation supplemented by theses two compnents and 2 g.L-1 of K 2 HPO 4 and finally the fermentation treated by theses three substances and 2 g.L-1 of triammonium citrate. During the fermentation time, a significant growth of Lb. plantarum was observed in carob syrup enriched by different components of MRS. The optical density evolves from 4.56 to 13.87 after 24 h of growth. The highest value of lactic acid 49.34 g.L-1 was obtained in carob syrup enriched by 10 g.L-1 of beef extract followed by carob syrup supplemented by all components 46.29 g.L-1 , then carob treated by all components except triammonium citrate 43.64 g.L-1 , and carob enriched by beef and yeast extracts 40.6 g.L-1 , finally fermentation control 14.69 g.L-1. The carob syrup enriched by 10g.L-1 of beef extract seems to be a good medium for lactic acid production by Lb. plantarum.
... The large availability of these materials, along with their low or even very low costs, makes them alternative sources of substrates that could be used for bacteria cultivations. Carob bean syrup was used as a culture medium to produce several bio-molecules such as ethanol (Roukas, 1994a, b;Turhan et al., 2008;Mazaheri et al., 2012;Germec et al., 2015), citric acid (Roukas, 1999) or lactic acid (Turhan et al., 2010). Enhancement attempts of Lactic acid production from carob bean syrup using fermentation process, such as the addition of sodium acetate and Tween 80 , and using invertase enzyme for hydrolyze of sucrose (Turhan et al., 2010), however, the addition of MRS components has not been characterised yet. ...
... Carob tree is a sugar-rich biomass which may theoretically be ideal for biofuel production carob [11]. Several studies have delved into the production of ethanol from carob pod, showing its technical and economical competitiveness compared with other traditional crops [12][13][14]. Other works have also assessed the use of this dryland forest crop for the efficient production of biohydrogen [15]. ...
This research presents a thorough analysis of the nutrients and anti-nutrients contained in different products from Algerian carob tree, Ceratonia siliqua L. (pod, pulp, seeds and leaves). Other parameters such as moisture, ash content and calorific value were also determined. The main purpose was to characterize these products derived from carob tree and analyze their possible valorization in several fields such as chemical, energy or medical industries. The results show that these products contain low amount of crude lipids (2.4-4.5%), moderate amounts of protein (4-7.4%) and high levels of total sugar (up to 66.6%). The compositional analysis reveals high nutritional values but, at the same time, it is also worth underscoring their high content in anti-nutrients: (i) trypsin inhibitor (6.4-7.3 mg·g⁻¹); and (ii) phytic acid (0.6-0.94 mg·g⁻¹). This work quantifies these two secondary metabolites in carob tree products for the first time. Finally, based on the results obtained, a process scheme is proposed for the complete use of carob tree products, including the use of anti-nutrients (trypsin inhibitors and phytic acid) for bio-medical applications since many research studies support that these compounds have great potential in this field.
... The effect of carob and germ flour addition in gluten-free bakery products has been also reported [18][19][20], whereas the alternative uses of carob fruit are still examined. Carob seed residues were proposed as substrate or soil organic amendment [21], and the carob pods were recommended for the production of bioethanol after fermentation [22]. ...
Carob samples from seven different Mediterranean countries (Cyprus, Greece, Italy, Spain, Turkey, Jordan and Palestine) were analyzed using Fourier Transform Infrared (FTIR) spectroscopy. Seed and flesh samples of indigenous and foreign cultivars, both authentic and commercial, were examined. The spectra were recorded in transmittance mode from KBr pellets. The data were compressed and further processed statistically using multivariate chemometric techniques, including Principal Component Analysis (PCA), Cluster Analysis (CA), Partial Least Squares (PLS) and Orthogonal Partial Least Square-Discriminant Analysis (OPLS-DA). Specifically, unsupervised PCA framed the importance of the variety of carobs, while supervised analysis highlighted the contribution of the geographical origin. Best classification models were achieved with PLS regression on first derivative spectra, giving an overall correct classification.
Thus, the applied methodology enabled the differentiation of carobs flesh and seed per their origin.
Our results appear to suggest that this method is a rapid and powerful tool for the successful discrimination of carobs origin and type.
... These strategies represent efficient bioethanol production using different A-IR and yeast strains for these proposes, e.g. wheat straw (Chen et al. 2007), sweet sorghum (Yu and Tan 2008, Molaverdi et al. 2013, Madhuca Latifolia L. (Mohanty et al. 2009), grape and sugar beet pomaces (Rodríguez et al. 2010) rice straw (Roslan et al. 2011), sugarcane bagasse (Shaibani et al. 2011), sweet potato (Swain et al. 2013) using Saccharomyces cerevisiae, carob pods using Zymomonas mobilis (Mazaheri et al. 2012), and sweet sorghum using Mucor indicus (Molaverdi et al. 2013). SSF presents some advantages for ethanol production contrasted with SF, e.g. ...
Solid state fermentation is currently used in a range of applications including classical applications, such as enzyme or antibiotic production, recently developed products, such as bioactive compounds and organic acids, new trends regarding bioethanol and biodiesel as sources of alternative energy, and biosurfactant molecules with environmental purposes of valorising unexploited biomass. This work summarizes the diversity of applications of solid state fermentation to valorize biomass regarding alternative energy and environmental purposes. The success of applying solid state fermentation to a specific process is affected by the nature of specific microorganisms and substrates. An exhaustive number of microorganisms able to grow in a solid matrix are presented, including fungus such as Aspergillus or Penicillum for antibiotics, Rhizopus for bioactive compounds, Mortierella for biodiesel to bacteria, Bacillus for biosurfactant production, or yeast for bioethanol.
... Carob kibble is rich in polyphenols with a good concentration of about 1.7% (Makris & Kefalas, 2004). In fact, carob has pod-like fruit whose beans (seeds) are used in the manufacturing of food grade gum (Karababa & Coşkuner, 2013) while de-seeded carob pods commonly called kibble are mainly used as feed (Karabulut, Canbolat, & Kamalak, 2006;Kotrotsios, Christaki, Bonos, & Florou-Paneri, 2010Kotrotsios, Christaki, Bonos, Florou-Paneri, & Spais, 2011;Obeidat, Alrababah, Alhamad, Gharaibeh, & Ishmais, 2012) and bioethanol production (Ercan, Irfan, & Mustafa, 2013;Mazaheri, Shojaosadati, Mousavi, Hejazi, & Saharkhiz, 2012;S anchez-Segado et al., 2010S anchez-Segado et al., , 2012. Carob (Ceratonia siliqua), belongs to the family Leguminosae (subfamily Caesalpiniodeae), is a perennial plant having more than hundred years of productive life period. ...
... The use of SSF has recently gained attention in the field of bioenergy production, particularly ethanol production. Feedstocks such as sweet sorghum stalks and bagasse [18,19], mahula flowers (Madhuca latifolia L.) [20], carob pods [21], and rice husk and bran [22] were used as the substrates for solid-state ethanol fermentation with satisfactory yield up to 225 g ethanol/kg substrate [20], whereas mushroom cultivation waste was fermented, yielding 0.29 mmol H 2 /g VS, equivalent to approximately 6.5 mL/g VS [14]. However, to the best of our knowledge, no reports on ASSF of microalgal biomass for hydrogen production have been available. ...
A considerable amount of volatile solids (VS) contained in the biomass of microalgae makes it promising for use as feedstock in fermentation processes. In this study, a biomass of microalga Chlorella sp. was used as a sole substrate for hydrogen production in an anaerobic solid-state fermentation (ASSF). Optimization of the process was investigated on the selected critical variables, i.e., total solid (TS) content, initial pH, and feed to inoculum (F/I) ratio (on a VS basis) using response surface methodology (RSM) with central composite design (CCD). TS content and F/I ratio were found to have statistically significant effects on hydrogen production. Maximal hydrogen production of 165 ± 12 mL H2, equivalent to 18.58 mL H2/g VS and 0.28 L H2/L reactor·d, was achieved under the optimal conditions of 38.83% TS, pH 6.03, and an F/I ratio of 4.33. Acetic and butyric acids were found to be main soluble microbial products (SMPs) in the fermented biomass. Based on the compositions of the biomass, an equation for theoretical bioconversion of Chlorella sp. biomass to hydrogen was proposed.
... The RS concentration in hydrolysate was determined by 3 ,5 -dinitrosalicylic acid (DNS) method [26]. Prior to the measurement, supernatant of the collected sample was treated with 1.0 N HCl at pH 1.0 at 85°C followed by neutralization with 1.0 N NaOH to hydrolyze sucrose into glucose and fructose [27]. Ethanol concentration was estimated by dichromate oxidation method [28]. ...
... Hapalopilus croceus, Irpex lacteus, Phanerochaete chrysosporium [203] Olive Mill Wastewater Peoxidases Agrocybe cylindracea, Inonotus andersonii, Pleurotus ostreatus and Trametes versicolor [204] Atrazine Ligninolytic enzymes Pleurotus ostreatus [205] 2,4 Dichlorophenol Ligninolytic enzymes Phanerochaete chrysosporium [206] Bentazon Laccase and Manganese peroxidase Ganoderma lucidum [207] Heptaclor Ligninolytic enzymes Phlebia acanthocystis, P. brevispora, Phlebia lindtneri and Phlebia aurea [208] Methylene blue Mangenese peroxidase Phanerochaete chrysosporium [209] Versatile peroxidase and laccase Pleurotus ostreatus [210] coracryl brilliant blue, Ligninolytic enzymes Phanerochaete chrysosporium, Phlebia brevispora and Phlebia floridensis [211] graphene Lignin peroxidase White rot fungi [212] Carob pod, Wheat bran Zymomonas mobilis [213] Sweet Sorghum Bagasse ...
Lignocellulosics are widely available natural products which are the tremendous source for the production of enzymes being used for the numerous applications in food, feed, paper, textile and agro-biotechnological industries, ethanol production, bioremediation processes and many more. Enzyme productions from microorganisms are stimulated aggressively through solid state fermentation which meets the demand of getting rid of agro-industrial waste and strengthen the consumption of renewable resources through biotechnology. Though well-developed techniques for enzyme production by submerged fermentation has been found very successful at the industrial sectors; solid state fermentation helps to overcome to the issues of production cost and high yield. Additionally the availability of the substrate with very much economical rate can compensate the overall economic expenses which promote the application of solid state fermentation at industrial level. However several reports regarding fermentation techniques and their pre-treatments are available, the present review will discuss about utilization of lignocellulosics through solid state fermentation for production of enzymes and their enhanced applications in different sectors in recent years.
... Carob kibble is high in sugar content which ranges from 30% to 60% with the main sugars being sucrose (65% to 75% of the total sugars), fructose and glucose (15% to 25% of the total sugars) (Ayaz and others 2007; Biner and others 2007; El Batal and others 2011). The high sugar content makes them suitable for citric acid production by Aspergillus niger (Roukas 1998), lactic acid fermentation by Lactobacillus casei (Turhan and others 2010), and bioethanol production, preferably by solid-state fermentation with Saccharomyces cerevisiae (Roukas 1994a, 1994a, 1996; Ercan and others 2013) or Zymomonas mobilis (Mazaheri and others 2012; Saharkhiz and others 2013). Carob kibble also contains appreciable amounts of fiber (up to 40%), protein (2% to 7%) and minerals such as potassium (993 to 1089 mg/100 g), calcium (266 to 319 mg/100 g), phosphorous (76 to 79 mg/100 g), and magnesium (55 to 56 mg/100 g) and low levels of fat (0.9% to 1.3%) (Albanell and others 1991; Shawakfeh and Erefej 2005; Turhan and others 2006; Turhan 2011; Khlifa and others 2013). ...
Carob (Ceratonia siliqua L.) is well known for its valuable locust bean gum obtained from the carob seeds. Separation of seeds from the pod leaves behind the carob kibble which is a good source of dietary fiber, sugars, and a range of bioactive compounds such as polyphenols and pinitol. Bioactive compounds present in carob kibble have been found to be beneficial in the control of many health problems such as diabetes, heart diseases, and colon cancer due to their antidiabetic, antioxidant, and anti-inflammatory activities. Carob kibble has substantial potential to be used as a food ingredient. This article focuses on the composition, health benefits, and food applications of carob kibble.
... The RS concentration in hydrolysate was determined by 3 ,5 -dinitrosalicylic acid (DNS) method [26]. Prior to the measurement, supernatant of the collected sample was treated with 1.0 N HCl at pH 1.0 at 85°C followed by neutralization with 1.0 N NaOH to hydrolyze sucrose into glucose and fructose [27]. Ethanol concentration was estimated by dichromate oxidation method [28]. ...
Requirement of costly enzymes (α-amylase and glucoamylase) for converting starch into glucose before fermentation is considered one of the cost increasing factors for corn ethanol. Enzyme consumptions can possibly be reduced during dry-grind ethanol production by increasing free sugar contents in corn kernels that will be released and fermented simultaneously with the product of starch hydrolysis, producing an additional amount of ethanol without consuming any enzyme. A comparative study was conducted to evaluate the effect of kernel sugars on enzyme requirement and yields of both hydrolysis and fermentation, using four high sugary corn genotypes (HSGs) and their parent field corns (PFCs). Enzymatic hydrolysis of the genotypes with four enzyme loads (1, 2, 3 and 4 kg MT−1 of dry corn) showed that HSGs produced higher proportions of reducing sugars (RS) in all conditions than PFCs did. Sufficient amounts of RS were produced by HSGs utilizing an enzyme load of 3 kg MT−1, whereas, PFCs consumed 4 kg MT−1 for their best yields. Likewise, HSGs produced higher concentrations of ethanol consuming lower amount of enzymes during fermentation. Therefore, HSGs could be considered as potential feedstocks for enhancing ethanol yield and reducing enzyme consumptions during dry-grind ethanol production.
... Although an increase in PD could promote release of hexose and pentose, high monosaccharide concentration could lead to product inhibition by glucose of the cellulases [17]. Moreover, monosaccharide accumulation could lead to the inhibition of microbial growth and slowed down the metabolism [18]. At the same time, slow heat dispersion along with too rapid saccharification may have resulted in heat accumulation and temperature elevation [19], which consequently could decrease enzyme activities and cell viability. ...
Ethanol production from NaOH-Pretreated solid state fermented sweet sorghum bagasse with an engineered strain of Z. mobilis TSH-ZM-01 was optimized. Results showed that: (1) residual solid removal during ethanol fermentation was unnecessary and 24 h fermentation duration was optimal for ethanol production; (2) ethanol yield of 179.20 g/kg of solid state fermented sweet sorghum bagasse achieved under the optimized process conditions of cellulase loading of 0.04 g/g-glucan, xylanase loading of 0.01 g/g-xylan, liquid to solid ratio of 9: 1 and pre-hydrolysis duration for 72 h.
... An important renewable energy, bioethanol has been recognized as one of the best alternative and environmental friendly fuels, which can reduce net greenhouse gas emissions [1,2]. Among many microorganisms that have been exploited for alcohol fermentation, Zymomonas mobilis has been considered as a promising alternative to Baker's yeast due to its higher ethanol tolerance and improved rates of sugar uptake [3]. ...
... Nowadays, the primary uses of the pods are as animal feed (Obeidata et al. 2011) or production of bioethanol (Mazaheri et al. 2012). For humans, carob pods have been used primarily in traditional foods such as confectioneries, beverages, bread or pasta in a few countries in the Mediterranean region because of their low price (Nyerges 1978;Brand 1984;Yousif and Alghzawi 2000;Ayaz et al. 2007). ...
The chemical, functional and sensory properties of carob juice compared with grape juice were evaluated. Composition results showed that carob pods contained high concentrations of carbohydrate and phytochemicals, moderate amounts of proteins and fiber, and low amounts of fat and ash. Phytochemical results showed that carob particle and powder juices had significantly higher total phenolic (19.8 and 20.3 mg gallic acid equivalent [GAE]/g, respectively) and tannin (4.3 and 4.5 mg catechin equivalents [CE]/g, respectively) contents than grape juice (6.2 mg GAE/g and 0.43 mg CE/g), while grape juice was higher in IC50 (10.8 mg/mL) than carob particles and powder juices (9.1 and 9.4 mg/mL, respectively). Descriptive results showed minor differences between grape and carob juices. In terms of consumer evaluation, the carob juices were similar to grape juice despite small differences especially in carob particle juice. Although carob juice is not traditionally considered as grape juice, it was found to be of acceptable overall quality.
Carob is produced by the evergreen sclerophyllous trees (Ceratonia siliqua L.), which are considered typical plants of Mediterranean countries. World production is estimated at about 315,000 tons per year. The carob pods are rich in carbohydrates, polyphenolic compounds, and antioxidant and free radical-scavenging compounds and contain low amounts of insoluble dietary fibers, protein, minerals and lipids. Nowadays, the primary uses of the pods are as animal feed. For humans, carob pods have been used primarily in traditional foods such as confectioneries, beverages, bread or pasta in a few countries in the Mediterranean region because of their low price. Carob pods could be expected to produce high-quality juice, which is acceptable to consumers with potential functional food impact. Thus, the present investigation evaluates the functional and sensory properties of newly developed carob juice.
... An important renewable energy, bioethanol has been recognized as one of the best alternative and environmental friendly fuels, which can reduce net greenhouse gas emissions [1,2]. Among many microorganisms that have been exploited for alcohol fermentation, Zymomonas mobilis has been considered as a promising alternative to Baker's yeast due to its higher ethanol tolerance and improved rates of sugar uptake [3]. ...
This paper deals with the decentralized control design for ethanol fermentation by
Zymomonas mobilis. Extractive fermentation has been proposed to improve the ethanol yield and
productivity due to product inhibition. The complexity of biological systems and significant process
variability can always lead to ineffective control system performance. In this paper, a 2x2 and 3x3
multi-scale control systems have been proposed. It is shown that the PID control design based on the
multi-scale control scheme is effective for complex high-order systems.
The effects of solid-state fermentation (SSF) with Lactiplantibacillus plantarum, Saccharomyces cerevisiae, Rhizopus oryzae, Aspergillus oryzae, and Neurospora sitophila were determined on the bioactive compound content and grain microstructure of brown rice (BR). After SSF, the β-glucan, arabinoxylans, γ-oryzanol, thiamine, riboflavin, phenolic, and flavonoid contents increased by 147, 11.2, 30.5, 16.9, 21.1, 76%, and 49.6%, respectively, indicating a marked increase in bioactive compound content. In addition, the water-soluble dietary fiber and arabinoxylan contents, and free phenolic and flavonoid contents significantly increased (p < 0.05). These changes were consistent with the microstructural changes observed after SSF, i.e., the outer cortex was rough, cracked, porous and separated from the starch endosperm, which was also cracked and porous; this should increase the dietary bioavailability of the bioactive compounds. SSF, especially with A. oryzae and Lb. plantarum, greatly enhanced the bioactive compound content in BR and has great potential in BR processing.
The carob tree (Ceratonia siliqua L.) is a forest tree with a wide distribution in northern Algeria and around the Mediterranean. It is listed among the under-utilized species whose development and cultivation are to be encouraged. However, good valuation of the species requires knowledge of its genetic resources.
Seven (07) Algerian provenances of the carob tree extending from Tlemcen, in the west, to Annaba, in the east, and covering different bioclimates (semi-arid, sub-humid and humid) and different altitudes (32 to 1050 m ), were studied for leaf, pod and seed morphology and the content of some physicochemical parameters of pulps, seeds and leaves.
Random sampling on 20 trees per provenance at a rate of 20 pods and 20 mature leaves per tree was carried out. That is a total of 140 trees, 2800 pods, 2800 seeds and 2800 leaves measured for quantitative characteristics (leaf size, number of leaflets per leaf, size of pods and seeds, total pod weight, number of seeds per pod, seed yield) and qualitative traits (pod and seed color, shape and surface; leaf color and presence / absence of the terminal leaflet).
The physicochemical study of the three plant parts (leaf / pulp / seed) focused on the dry matter content, the ash, fat and total sugars content.
Results showed a significant variability in the pod, seed and leaf morphology among the carob tree provenances.
Leaf morphological study provided data on such trait characteristics for the first time on the Algerian carob tree.
The biochemical study showed in particular the superiority of certain provenances for the pulp sugar content.
Provenance clustering indicates, however, that the variability evidenced does not reflect the conditions (i.e. bioclimate, altitude and continentality) at the site of origin.
The morphological study indicates the existence of provenances at the top position and others at the bottom position for pod and leaf dimensions, while the biochemical study, in particular the pulp total sugar content, does not confirm this ranking.
Keywords : Ceratonia siliqua L., Algeria ; morphology ; phytochemistry ; provenance ; variation.
Le caroubier (Ceratonia siliqua L.) est un arbre forestier à large répartition en Algérie du nord et dans le pourtour méditerranéen. Il est répertorié parmi les espèces sous-utilisées et dont la valorisation et la culture sont à encourager. Toutefois, une bonne valorisation nécessite la connaissance de la ressource génétique de l’espèce.
Sept (07) provenances algériennes du caroubier s’étendant depuis Tlemcen, à l’Ouest, jusqu’à Annaba, à l’Est, et couvrant différents bioclimats (semi-aride, subhumide et humide) et différentes altitudes (32 à 1050 m), ont été étudiées pour la morphologie des feuilles, des gousses et des graines et la teneur en quelques paramètres physico-chimiques des pulpes, des graines et des feuilles.
Un échantillonnage aléatoire sur 20 arbres par provenance à raison 20 de gousses et de 20 feuilles matures par arbre a été fait. Soit un total de 140 arbres, 2800 gousses, 2800 graines et 2800 feuilles mesurées pour les caractères quantitatifs (taille de la feuille, nombre de folioles par feuille, taille des gousses et graines, poids total, nombre de graines par gousse, rendement en graines) et qualitatifs (couleur, forme et aspect de la surface des gousses et des graines ; couleur de la feuille et présence/absence de la foliole terminale).
L’étude physico-biochimique des trois parties végétales (feuille/ pulpe/graine) a porté sur le taux de matière sèche, la teneur en cendres, en matière grasse et en sucres totaux.
Les résultats ont montré une variabilité significative de la morphologie des gousses, des graines et des feuilles du caroubier selon les provenances géographiques.
L’étude morphologique des feuilles a permis de fournir des données sur ses caractères pour la première fois chez le caroubier algérien.
L’étude biochimique a montré notamment la supériorité de certaines provenances pour le taux de sucres des pulpes.
Le classement des provenances indique toutefois que la variabilité mise en évidence ne reflète pas les conditions (i.e. bioclimat, altitude et continentalité) du site d’origine.
L’étude morphologique indique l’existence de provenances bien classées et d’autres mal classées aussi bien pour les dimensions des gousses que des feuilles, tandis que l’étude biochimique, en particulier la teneur en sucres totaux des pulpes, ne conforte pas ce classement.
Mots clés : Ceratonia siliqua L., Algérie, morphologie, phytochimie, provenance, variabilité.
شجرة الخروب (Ceratonia siliqua L.) هي شجرة غابية واسعة الانتشار في شمال الجزائر وفي منطقة البحر الأبيض المتوسط. وهذا النوع مدرج ضمن الأنواع التي لم تُستغل استغلالاً كافياً والتي ينبغي تشجيع تقييمها وزراعتها. الا أن التقييم الجيد يتطلب معرفة الموارد الوراثية للأنواع.
في سبعة (07) مناطق جزائرية للخروب تمتد من تلمسان غربا، إلى عنابة شرقا وتشمل ظروف مناخية متنوعة من رطبة الى شبه جافة وعلى ارتفاعات مختلفة (32 إلى 1050 م). من أجل دراسة مورفولوجيا الأوراق، والقرون، والبذور، ومحتوى بعض الخصائص الفيزيوكيميائية للب، والبذور، والأوراق.
أخذنا عينات عشوائية من 20 شجرة لكل منطقة مع 20 قرنا و20 ورقة بالغة لكل شجرة. وما يقاس مجموعه 140 شجرة، و2800 قرن، و2800 بذرة و2800 ورقة، لدراسة الخصائص الكمية (حجم الورقة، وعدد الوريقات لكل ورقة، وحجم القرون والبذور، والوزن الكلي، وعدد البذور لكل قرن، والمردود). والخصائص النوعية (لون وشكل ومظهر سطح القرن والبذور؛ لون الورقة وعدم وجود الوريقة الطرفية).
وفحصنا من خلال الدراسة الفيزيوكيميائية للأجزاء النباتية الثلاثة (ورقة/لب/بذرة) محتوى المادة الجافة والرماد والدهون والسكر الكلي.
وأظهرت النتائج تبايناً كبيراً في مورفولوجيا القرون والبذور وأوراق الخروب بين المناطق الجغرافية.
وقد أتاحت الدراسة المورفولوجية للأوراق تقديم بيانات عن هذه الصفات لشجرة الخروب لأول مرة في الجزائر.
وأظهرت الدراسة الفيزيوكيميائية بشكل خاص تفوق مناطق معينة على محتوى السكر في اللب.
ومع ذلك، فإن تصنيف المناطق يشير إلى أن التباين الذي تم تسليط الضوء عليه لا يعكس الظروف المناخية او الارتفاع لموقع المنطقة.
وتشير الدراسة المورفولوجية إلى وجود مناطق مصنفة بشكل جيد ومناطق أخرى غير مصنفة لكل من أبعاد القرون والأوراق، في حين أن الدراسة الفيزيوكيميائية، ولا سيما المحتوى الكلي للسكر في اللب، لا تدعم هذا التصنيف.
الكلمات المفتاحية: شجرة الخروب – الجزائر – مورفولوجيا – فيتو كيمياء – منطقة – تغيرات.
Depletion of petroleum resources, rising fuel prices, and climate change are some of the recent concerns that have escalated the research on alternative energy sources. Biofuels like bioethanol, biobutanol, biohydrogen, and methane are substitute to fossil fuels. Microbial-based bioconversion processes is a sustainable approach to produce these biofuels from renewable feedstock. Microorganisms not only secrete industrially important enzymes like cellulases, xylanase, chitinases, amylases, etc. that degrade biopolymers (cellulose, hemicelluloses, chitin, etc.) into monomeric sugars but also ferment them into energy-dense biomolecules. In this regard, ethanologenic yeasts like Scaccharomyces cerevisiae and Zymomonas mobilis have been used extensively for the industrial production of ethanol. Butanol is another important organic solvent that can be obtained from biomass by fermentation using the bacterium Clostridium acetobutylicum. Some microbes can accumulate lipids even up to 65%–70% of biomass. Such oleaginous microorganisms like Yarrowia, Lipomyces, and Rhodosporidium are used for the production of Fatty acid alkyl esters (marketed as biodiesel) and other lipid-based oleochemicals. Biohydrogen is another clean energy source (as it produces only water as by-product) produced by the dark fermentation process using facultative anaerobes like Enterobacter cloacea. Some microbes can also utilize carbon dioxide to produce methane or biogas. These methanogenic microbes inhabit extreme environments. Thus, microbes are important in the sustainable production of biofuels and bioenergy products. Bioenergy research is crucial for the economic stability and energy security of a nation. Moreover, it is an indispensable contribution to the global effort in reducing greenhouse gas emission and promote sustainable fuels.
Use of a membrane within a bioreactor (MBR), either microbial or enzymatic, is a technology that has existed for 30 years to increase process productivity and/or facilitate the recovery and the purification of biomolecules. Currently, this technology is attracting increasing interest in speeding up the process and in better sustainability. In this work, we present the current status of MBR technologies. Fundamental aspects and process design are outlined and emerging applications are identified in both aspects of engineering, i.e., enzymatic and microorganism (bacteria, animal cells, and microalgae), including microscale aspects and wastewater treatment. Comparison of this integrated technology with classical batch or continuous bioreactors is made to highlight the performance of MBRs and identify factors limiting their performance and the different possibilities for their optimization.
In this work, mathematical modelling of ethanol production in solid-state fermentation (SSF) has been done based on the variation in the dry weight of solid medium. This method was previously used for mathematical modelling of enzyme production, however, the model should be modified to predict the production of a volatile compound like ethanol. The experimental results of bioethanol production from the mixture of carob pods and wheat bran by Zymomonas mobilis in SSF were used for the model validation. Exponential and logistic kinetic models were used for modelling the growth of microorganism. In both cases, the model predictions matched well with the experimental results during the exponential growth phase, indicating the good ability of solid medium weight variation method for modelling a volatile product formation in solid-state fermentation. In addition, by using logistic model, better predictions were obtained.
Özet: Akdeniz ikliminin hakim olduğu bölgelerde doğal olarak yetişen keçiboynuzu, ağacından meyvesine, meyvesinden tohumuna çok farklı amaçlarla kullanılmaktadır. Meyve ve tohumunun sanayi ile entegre olması, bu türün ekonomik değerini daha da arttırmaktadır. Ülkemizde keçiboynuzu yöresel olarak " Harnup " , " Harup " , " Boynuz " , " Buynuz " ve " Kerti " gibi isimlerle anılmaktadır. Çalı veya ağaç formunda büyüme özelliğine sahiptir. Keçiboynuzu ile ilgili ülkemizde kapama bahçeler henüz yaygın olmamakla birlikte, son yıllarda orman ve hazine arazilerinin kiralama yoluyla halka arz edilmesi, keçiboynuzu plantasyonlarının kurulumunu popüler hale getirmiştir. Keçiboynuzu meyve ve tohumu yanında, ağacının herdemyeşil olması nedeniyle peyzaj amaçlı kullanımı da yaygındır. Ayrıca, yapraklarının yangına dayanıklı olmasından dolayı, orman alanlarında yangın koruma hattı olarak da kullanılmaktadır. Keçiboynuzunun meyvesi, geleneksel olarak yüzyıllardır pekmez yapımında değerlendirilmektedir. Buna ilave olarak, meyvesi öğütülerek kahve, kakao ve un elde edilmekte ve sanayide farklı alanlarda kullanılmaktadır. Keçiboynuzu meyvesi potasyum ve kalsiyum mineralleri ile karbonhidrat ve lif bakımından zengindir. Meyvesinin sağlıkta farklı kullanım alanları ile ilgili çok sayıda araştırmalar bulunmaktadır. Özellikle kolestorolün düşürülmesinde, ishali önlemede, osteoporoz, antideprasan, deri hastalıkları ile kanser mücadelesinde kullanılmaktadır. Tohumunun galaktomannanca zengin olması nedeniyle keçiboynuzu zamkı üretilmekte ve piyasada E-410 (gıda katkı maddesi) adlı katkı maddesi olarak isimlendirilmektedir. E-410 farklı endüstrilerde (gıda, petrokimya, kağıt, tekstil vb.) çok amaçlı kullanım alanına sahiptir. Tohumun embriyosu ise protein bakımından oldukça zengindir. Bu derlemede, keçiboynuzunun çevre, beslenme ve sağlık üzerine etkileri konusunda bilgiler verilmiştir. Anahtar Kelimeler: Ceratonia siliqua, Yangın set bitkisi, E-410, Galaktomannan, Un, Lif
. Environment, Industrial Use and Human Health Aspects of Carob
Abstract: Carob tree is grown naturally in Mediterranean climate and its fruit and seed and plants are used for many different purposes. Industrial integration of pods and seeds has facilitated for intensifying its economic value. Many diverse names used such as " Harnup " , " Harup " , " Boynuz " , " Buynuz " and " Kerti " in different districts. Carob plants show either a tree form or bushy habitat. Although there is no commercial scale carob plantations in Turkey, recent long term rental policy of state lands had made popular to establish large carob plantations. Besides pods and seeds, the tree itself is a popular landscape tree due to its distinguished evergreen characteristic. Carob leaves are naturally quite resistant to fire and became a popular plant for forest fire protection line. For hundreds of years, carob pods have been traditionally used to produce molasses. Furthermore, grinded carob pods for coffee, cacao and flour become popular ingredients in many industrial products. Pods are important source of fiber, carbohydrate and potassium and calcium minerals. They are effective on lowering cholesterol, preventing diarrhea, osteoporosis, antidepressant, skin diseases and fighting in some of the cancer tumors. Important asset of seed is the high amount of galactomannan content. The ground of endosperm is used to produce locust bean gum, E-410 coded food additive. E-410 is used in many diversified industries including food, petro chemistry, paper, textile etc. The impacts of carob on environment, human nutrition and health are reviewed in this study.
The exploitation of rich in sugars lingo-cellulosic residue of carob pods for bio-ethanol and bio-electricity generation has been investigated. The process could take place in two (2) or three (3) stages including: a) bio-ethanol production originated from carob pods, b) direct exploitation of bio-ethanol to fuel cells for electricity generation, and/or c) steam reforming of ethanol for hydrogen production and exploitation of the produced hydrogen in fuel cells for electricity generation. Surveying the scientific literature it has been found that the production of bio-ethanol from carob pods and electricity fed to the ethanol fuel cells for hydrogen production do not present any technological difficulties. The economic viability of bio-ethanol production from carob pods has not yet been proved and thus commercial plants do not yet exist. The use, however, of direct fed ethanol fuel cells and steam reforming of ethanol for hydrogen production are promising processes which require, however, further research and development (R&D) before reaching demonstration and possibly a commercial scale. Therefore the realization of power generation from carob pods requires initially the investigation and indication of the appropriate solution of various technological problems. This should be done in a way that the whole integrated process would be cost effective. In addition since the carob tree grows in marginal and partly desertified areas mainly around the Mediterranean region, the use of carob’s fruit for power generation via upgrading of its waste by biochemical and electrochemical processes will partly replace fossil fuels generated electricity and will promote sustainability.
Solid-state fermentation (SSF) has advantages, such as lower water use and higher volumetric productivity, over those of submerged fermentation. As a result, SSF technology has drawn increasing attention in the past few decades. In this chapter, different types of SSF bioreactors, including tray, packed-bed, rotating/stirred-drum, fluidized-bed, rocking-drum, and stirred-aerated bioreactors, are discussed. Progress in reactor design, heat and mass transfer, and operational strategies are reviewed. Growth of microorganisms in SSF is also discussed in terms of classification, modeling, and effects on the performance of SSF. Two major challenges in industrial applications of SSF, namely heat transfer on a large scale and quantitative characterization of fungal growth, are also discussed. Future research and development of SSF should focus on high-value fermentation products that can be economically feasible on a relatively small scale. Also, online nondestructive detection methods are desired for the characterization and control of organism growth during SSF processes.
Algae Spirogyra have the potential to be developed as a raw material for bioethanol production. This study aims to determine the effect of the hydrolysis process of algae Spirogyra on total sugar production. The hydrolysis process of Spirogyra hyalina was carried out using a variation of heating duration and type of enzyme. This study also aimed to determine the effect of fermentation duration and the addition of nutritional fermentation on the reducing sugar, pH changes, microbial biomass and ethanol production from algae Spirogyra hyalina by using Zymomonas mobilis. The fermentation process was carried out in anaerobic conditions using a modified fermentor for 96 hours. Results showed the differences the hydrolysis process of algae Spirogyra hyalina affected on sugar levels. The highest sugar level was achieved by a combination of α-amylase and β-amylase enzymes. Fermentation duration and nutritional fermentation affected reducing sugar, pH substrate, microbial biomass and ethanol levels produced from the fermentation of algae Spirogyra by using Zymomonas mobilis.
This work is a review of some previous factors involved in bioethanol production. The first part focuses on the substrates that are being used for the production of bioethanol from the last decade to date, and to pretreatments applied to some substrates to promote the release of fermentable sugars present in them. Few comments are made about bioethanol production legislations in some countries, the required characteristics for its use as liquid fuel and some barriers that limit their production. It is shown that the production of bioethanol is a complex problem that is influenced by social, political and technological aspects.
A consolidated bioprocess integrating enzyme production, saccharification and fermentation was applied for bioethanol production. Mixed solid-state fermentation of alkali-pretreated sugarcane bagasse (SCB) supplemented with wheat bran (WB) to produce a compound enzyme for saccharification by Trichoderma and Penicillium was carried out, and at 72 h, the obtained sugars concentration was 20.190 g/L. Then the mixture was further converted to ethanol by inoculating Saccharomyces cerevisiae. After 24 h, the maximum ethanol concentration 5.825 g/L (40.84% of theoretical yield) was achieved. At 144 h, the produced β-glucosidase activity and fungal biomass were 0.483 IU/mL and 0.204 g/g, respectively. The consolidated bioprocess avoided enzyme preparation, saved much water/energy consumption and reduced equipment investment, which indicated that it might be an effective approach for the economic production of bioethanol.
This work is a review of some previous factors involved in bioethanol production. The first part focuses on the substrates that are being used for the production of bioethanol from the last decade to date, and to pretreatments applied to some substrates to promote the release of fermentable sugars present in them. Few comments are made about bioethanol production legislations in some countries, the required characteristics for its use as liquid fuel and some barriers that limit their production. It is shown that the production of bioethanol is a complex problem that is influenced by social, political and technological aspects.
A cost competitive integrated technology to convert solid state fermented sweet sorghum bagasse (SS) into cellulosic ethanol which combined ethanol distillation, NaOH pretreatment and simultaneous saccharification and co-fermentation (SSCF) was presented in this study. After solid-state fermentation, the SS was distilled with 10% (w/w dry material, DM) NaOH to separate sugar-based ethanol and pretreat lignocelluose simultaneously in one step and one distillation stripper, then the NaOH pretreated SS was subsequently converted into cellulosic ethanol by SSCF. Results showed that 69.49% ethanol theoretical yield was achieved under the optimal condition based on this novel integrated process. This integrated technology can significantly reduce the energy consumption and capital cost for cellulosic ethanol production, and ensure cellulosic ethanol produced from SS cost-effectively.
A mixture of carob pods and wheat bran as filler was evaluated as substrates for bioethanol production using Zymomonas mobilis in a 0.5 L-glass packed bed column fermenter. The experiments were initially performed under the optimum conditions defined previously in a flask-scale fermentation system. Under these conditions, removal of the generated heat and CO2 from the solid medium was more challenging than in the flask-scale system. In addition, the traditional aeration method was not applicable for removing the heat and CO2 since bioethanol production should be conducted under anaerobic conditions. The packed bed column system was modified, and an intermittent aeration method was used to remove the entrapped CO2 from the solid bed, thereby enabling the anaerobic condition to be maintained. The effect of operating temperature and carob particle size on the amount and rate of ethanol produced was also studied. We determined that the optimum operating conditions for this packed bed column fermentation system were 28 °C, a carob particle size of 1 mm, and 0.1 L min−1 intermittent aeration for 15 min each hour during the second 15 h of the fermentation process. Under these conditions 60.9 g ethanol per kilogram dry mixture of carob pod and wheat bran was produced.
Context: In this review, we discuss empirical and stoichiometric models, which have been developed recently in SSF processes and the influence of environmental conditions on the variables of these models. Additionally, new studies on modeling of product formation are also mentioned. Evidence Acquisition: Solid-state fermentation (SSF) is recognized as a cheap process for producing many valuable products like industrial enzymes and bioethanol. To develop, optimize, and scale-up this process, mathematical models are required. In this review, we collected all the papers regarding microbial growth and product formation modeling in SSF. The pros and cons of each model and confirmation with experimental data were also discussed. We discussed here the simple empirical growth kinetics models and the effect of environmental conditions on these models parameters, stoichiometric models and product formation models. Results: Simple empirical models are used widely in the kinetic modeling of SSF processes due to their simplicity and ease of use. However, more studies should be done in this field to make them more accurate, especially; the effect of environmental conditions, like temperature and moisture, on key variables of the model must be considered. Robust modeling methods, like stoichiometric models, are in their early stages in SSF processes and require more studies. Developing models in which transport phenomena models are coupled with the growth kinetics models can help better SSF bioreactor designing. On the other hand, to use SSF for producing valuable products, product formation models, which are not developed well in SSF processes, are necessary. Conclusions: To use SSF for producing valuable metabolites in large scales, more attention is required for modeling the SSF processes, especially for product formation models and using modern methods like stoichiometric models. © 2013, National Institute of Genetic Engineering and Biotechnology; Licensee Kowsar Ltd.
There is a growing interest worldwide to find out new and cheap carbohydrate sources for production of bioethanol. In this context, the production of ethanol from mahula (Madhuca latifolia L.) flowers by Saccharomyces cerevisiae in solid-state fermentation was investigated. The moisture level of 70%, pH of 6.0 and temperature of 30 °C were found optimum for maximum ethanol concentration (225.0 ± 4.0 g/kg flower) obtained from mahula flowers after 72 h of fermentation. Concomitant with highest ethanol concentration, the maximum ethanol productivity (3.13 g/kg flower/h), yeast biomass (18.5 × 108 CFU/g flower), the ethanol yield (58.44 g/100 g sugar consumed) and the fermentation efficiency (77.1%) were also obtained at these parametric levels.
Progressive depletion of conventional fossil fuels with increasing energy consumption and greenhouse gas (GHG) emissions have led to a move towards renewable and sustainable energy sources. In this work, carob pod (Ceratonia Siliqua) is proposed as an economical source for ethanol production, especially, in arid regions. The carob tree is an evergreen shrub native to the Mediterranean region, cultivated for its edible seed pods and it is currently being reemphasised as an alternative in dryland areas, because no carbon-enriched lands are necessary. The global process of bioethanol production from carob pod by Saccharomyces Cerevisiae yeast cells were analyzed in a previous work. To take into account environmental impacts of the process, a Life Cycle Assessment (LCA) technique was applied, which allowed detailed analysis of material and energy fluxes. On the life-cycle basis, the net energy yield of carob pod (2.36 MJ/MJ) was found to be similar than to those values for traditional crops (i.e. Wheat, 2.25 MJ/MJ).
The production of ethanol from carob pods extract by Saccharomyces cerevisiae in static and shake flask fermentation was investigated. Shake flask fermentation proved to be a better fermentation system for the production of ethanol than static fermentation. The external addition of nutrients into the carob pods extract did not improve the production of ethanol. The maximum concentration of ethanol (75 g/l) was obtained at an inoculum amount of 0.3%, a pH of 4.5, 30°C and an initial sugar concentration of 200 g/1. Under the same fermentation conditions both sterilized and non‐sterilized carob pods extract gave the same final ethanol concentration.
A suitable alternative to replace fossil fuels is the production of bioethanol from agroindustrial waste. Grape pomace is the most abundant residue in San Juan and sugar beet pomace could be important in the region. Solid-State Fermentation (SSF) is a technology that allows transforming agroindustrial waste into many valuable bioproducts, like ethanol. This work reports a laboratory scale SSF to obtain alcohol from grape and sugar beet pomace by means of Saccharomyces cerevisiae yeasts. The initial conditions of the culture medium were: sugars 16.5% (p/p); pH 4.5; humidity 68% (p/p). Cultures were inoculated with 108cells/g of pomace, and incubated in anaerobic environment, at 28°C, during 96h. SSF showed ethanol maximum concentrations at 48h and ethanol yield on sugars consumed was more than 82%. Yield attained creates expectation about the use of SSF to obtain fuel alcohol.
Solid state fermentation of chopped sweet sorghum particles to produce ethanol was studied statically using thermotolerant yeast. The influence of various process parameters, such as yeast cell concentration, particle size and moisture content, on the ethanol yield was investigated. Optimal values of these parameters were 4×106 cells/g raw sorghum, Dp=1.5 mm and 75%, respectively. Addition of reducing agent H2SO3 into the fermentation medium provided anaerobic condition, and obtained the maximum ethanol yield of 7.9 g ethanol per 100 g fresh stalks or 0.46 g ethanol/g total sugar, which was 91% of the theoretic yield.
The possibility of usingZymomonas
mobilis as the microorganism, in solid-state fermentation of sugar-beet particles was investigated. The major factors affecting the process were investigated and related to ethanol yield and productivity. Ethanol yield of 0.48 g/g sugar, volumetric productivity of 12 g/L h, and final ethanol concentration of 130 g/L show the good performance ofZ.mobilis in a solid-state fermentation.
Rochelle salt, normally present in the dinitrosalicylic acid reagent for reducing sugar, interferes with the protective action of the sulfite, but is essential to color stability. The difficulty may be resolved either by eliminating Rochelle salt from the reagent and adding it to the mixture of reducing sugar and reagent after the color is developed, or by adding known amounts of glucose to the samples of reducing sugar to compensate for the losses sustained in the presence of the Rochelle salt. The optimal composition of a modified dinitrosalicylic acid reagent is given.
The continuous production of ethanol from carob pod extract by immobilized Saccharomyces cerevisiae in a packed-bed reactor has been investigated. At a substrate concentration of 150 g dm−3, maximum ethanol productivity of 16 g dm−3 h−1 was obtained at D = 0·4 h−1 with 62·3% of theoretical yield and 83·6% sugars′ utilization. At a dilution rate of 0·1 h−1, optimal ethanol productivity was achieved in the pH range 3·5–5·5, temperature range 30–35·C and initial sugar concentration of 200 g dm−3. Maximum ethanol productivity of 24·5 g dm−3 h−1 was obtained at D = 0·5 h−1 with 58·8% of theoretical yield and 85% sugars′ utilization when non-sterilized carob pod extract containing 200 g dm−3 total sugars was used as feed material. The bioreactor system was operated at a constant dilution rate of 0·5 h−1 for 30 days without loss of the original immobilized yeast activity. In this case, the average ethanol productivity, ethanol yield (% of theoretical) and sugars′ utilization were 25 g dm−3 h−1, 58·8% and 85·5%, respectively.
The aim of the study was to determine the main sugar profiles of the pods, without the seeds, of cultivated and wild types of the carob bean grown in the Mediterranean and Aegean basin of Turkey. The most abundant sugar in the pods was sucrose with smaller amounts of glucose and fructose. The pods of cultivated varieties had a higher (p < 0.05) total sugar concentration of 531 ± 93 g/kg dry weight than the wild type selections which had 437 ± 77 g/kg. However, this difference was due to the greater concentration of sucrose in the cultivated varieties which did not differ from the wild types in their concentrations of fructose or glucose. The ratios of individual sugars to total sugars in the pods were similar in both varieties. There is a need to identify extreme wild types, including high seeds and low pod, and cultivated types, containing low seeds and high pod, rich in sugar for an exhaustive picture of the sugar profiles of the varieties.
Ethanol production from Canna edulis Ker was successfully carried out by solid state simultaneous saccharification and fermentation. The enzymatic hydrolysis conditions of C. edulis were optimized by Plackett–Burman design. The effect of inert carrier (corncob and rice bran) on ethanol fermentation and the kinetics of solid state simultaneous saccharification and fermentation was investigated. It was found that C. edulis was an alternative substrate for ethanol production, 10.1% (v/v) of ethanol concentration can attained when 40 g corncob and 10 g rice bran per 100 g C. edulis powder were added for ethanol fermentation. No shortage of fermentable sugars was observed during solid state simultaneous saccharification and fermentation. There was no wastewater produced in the process of ethanol production from C. edulis with solid state simultaneous saccharification and fermentation and the ethanol yield of more than 0.28 tonne per one tonne feedstock was achieved. This is first report for ethanol production from C. edulis powder.
The production of ethanol from carob pods by Saccharomyces cerevisiae in solid-state fermentation was investigated. The maximal ethanol concentration (1603 g/kg dry pods), ethanol productivity (6.7 0.2 g/kg per hour), ethanol yield (40 1.8%), biomass concentration (7.5 0.4 x 108 cells/g carob pulp) and fermentation efficiency (80 2%) were obtained at an inoculum amount of 3%, a particle size of 0.5 mm, a moisture level of 70%, a pH of 4.5 and a temperature of 30C. Under the same fermentation conditions both sterilized and non-sterilized carob pods pulp gave the same maximum ethanol concentration.
SSF offers numerous advantages over submerged fermentation (SmF). These include high volumetric productivity, relatively higher
concentration of the products, less effluent generation, and simple fermentation equipments, etc. The major factors, which
affect microbial growth and activity in SSF include the selection of a suitable micro-organism and substrate, pre-treatment
of the substrate, particle size (inter-particle space and surface area) of the substrate, moisture content and water activity
(aw) of the substrate, relative humidity, type and size of inoculum, temperature of fermenting matter, removal of metabolic heat
generated during respiration, period of cultivation, maintenance of uniformity in environment of SSF, and the gaseous atmosphere,
i.e. oxygen consumption rate and carbon dioxide evolution rate.
The nature and amounts of by-products formed during conversion of sugar beets to ethanol byZ.
mobilis in Conventional Submerged Fermentation (CSF) and Solid-State Fermentation (SSF) were investigated. It was found that the bacterium produced fewer by-products in SSF than CSF, and that by-products profile was different. The influence of fermentation temperature on synthesis of by-products in SSF was also studied. High fermentation temperature favoured sorbitol synthesis and low fermentation temperature the synthesis of levan. The best results were obtained at 35C. An ethanol yield of up to 95% of the theoretical value with final ethanol concentration of 142 g/L were obtained.
There is a growing interest worldwide to find out new and cheap carbohydrate sources for production of bioethanol. In this context, carob pod (Ceratonia siliqua) is proposed as an economical source for bioethanol production, especially, in arid regions. The carob tree is an evergreen shrub native to the Mediterranean region, cultivated for its edible seed pods and it is currently being reemphasised as an alternative in dryland areas, because no carbon-enriched lands are necessary. In this work, the global process of ethanol production from carob pod was studied. In a first stage, aqueous extraction of sugars from the pod was conducted, achieving very high yields (>99%) in a short period of time. The process was followed by acid or alkaline hydrolysis of washed pod at different operating conditions, the best results (R = 38.20%) being reached with sulphuric acid (2% v/v) at 90 °C, using a L/S (liquid/solid) ratio of 7.5 and shaking at 700 rpm for 420 min. After that, fermentation of hydrolysates were tested at 30 °C, 125 rpm, 200 g/L of sugars and 15 g/L of yeast with three different kinds of yeasts. In these conditions a maximum of 95 g/L of ethanol was obtained after 24 h. Finally, the distillation and dehydration of water–bioethanol mixtures was analyzed using the chemical process simulation software CHEMCAD with the aim of estimate the energy requirements of the process.
Our strong dependence on fossil fuels results from the intensive use and consumption of petroleum derivatives which, combined with diminishing oil resources, causes environmental and political concerns. The utilization of agricultural residues as raw materials in a biorefinery is a promising alternative to fossil resources for production of energy carriers and chemicals, thus mitigating climate change and enhancing energy security. This paper focuses on a biorefinery concept which produces bioethanol, bioenergy and biochemicals from two types of agricultural residues, corn stover and wheat straw. These biorefinery systems are investigated using a Life Cycle Assessment (LCA) approach, which takes into account all the input and output flows occurring along the production chain. This approach can be applied to almost all the other patterns that convert lignocellulosic residues into bioenergy and biochemicals. The analysis elaborates on land use change aspects, i.e. the effects of crop residue removal (like decrease in grain yields, change in soil N2O emissions and decrease of soil organic carbon). The biorefinery systems are compared with the respective fossil reference systems producing the same amount of products/services from fossils instead of biomass. Since climate change mitigation and energy security are the two most important driving forces for biorefinery development, the assessment focuses on greenhouse gas (GHG) emissions and cumulative primary energy demand, but other environmental categories are evaluated as well.
Bio-fuels are important because they replace petroleum fuels. A number of environmental and economic benefits are claimed for bio-fuels. Bio-ethanol is by far the most widely used bio-fuel for transportation worldwide. Production of bio-ethanol from biomass is one way to reduce both consumption of crude oil and environmental pollution. Using bio-ethanol blended gasoline fuel for automobiles can significantly reduce petroleum use and exhaust greenhouse gas emission. Bio-ethanol can be produced from different kinds of raw materials. These raw materials are classified into three categories of agricultural raw materials: simple sugars, starch and lignocellulose. Bio-ethanol from sugar cane, produced under the proper conditions, is essentially a clean fuel and has several clear advantages over petroleum-derived gasoline in reducing greenhouse gas emissions and improving air quality in metropolitan areas. Conversion technologies for producing bio-ethanol from cellulosic biomass resources such as forest materials, agricultural residues and urban wastes are under development and have not yet been demonstrated commercially.
Solid-state fermentation (SSF) has built up credibility in recent years in biotech industries due to its potential applications in the production of biologically active secondary metabolites, apart from feed, fuel, food, industrial chemicals and pharmaceutical products and has emerged as an attractive alternative to submerged fermentation. Bioremediation, bioleaching, biopulping, biobeneficiation, etc. are the major applications of SSF in bioprocesses which have set another milestone. Utilization of agro-industrial residues as substrates in SSF processes provides an alternative avenue and value-addition to these otherwise under- or non-utilized residues. Innovation is the key to success and it is imperative to be up-to-date with the changing demands of the industries and meet their needs for better product and services. Better understanding of biochemical engineering aspects, particularly on mathematical modeling and design of bioreactors (fermenters) has made it possible to scale-up SSF processes and some designs have been developed for commercialization, making the technology economically feasible. In future, SSF technology would be well developed at par with SmF if rationalization and standardization continues in current trend. This review describes the state-of-art scenario in totality on SSF although the focus is on the most recent developments of last 5 years or so on SSF processes and products developments.
A process for the production of ethanol from carob (Ceratonia siliqua) pods was designed and an economic analysis was carried out for a hypothetical plant. The plant was assumed to perform an aqueous extraction of sugars from the pods followed by fermentation and distillation to produce ethanol. The total fixed capital investment for a base case process with a capacity to transform 68,000 t/year carob pod was calculated as 39.61 millon euros (€) with a minimum bioethanol production cost of 0.51 €/L and an internal rate of return of 7%. The plant was found to be profitable at carob pod prices lower than 0.188 €/kg. An increase in the transformation capacity of the plant from 33,880 to 135,450 t/year was calculated to result in an increase in the internal rate of return from 5.50% to 13.61%. The obtained results show that carob pod is a promising alternative source for bioethanol production.
In this research, ethanol production from carob pod extract (extract) using Zymomonas mobilis with medium optimized by Plackett-Burman (P-B) and response surface methodologies (RSM) was studied. Z. mobilis was recognized as useful for ethanol production from carob pod extract. The effects of initial concentrations of sugar, peptone, and yeast extract as well as agitation rate (rpm), pH, and culture time in nonhydrolyzed carob pod extract were investigated. Significantly affecting variables (P = 0.05) in the model obtained from RSM studies were: weights of bacterial inoculum, initial sugar, peptone, and yeast extract. Acid hydrolysis was useful to complete conversion of sugars to glucose and fructose. Nonhydrolyzed extract showed higher ethanol yield and residual sugar compared with hydrolyzed extract. Ethanol produced (g g(-1) initial sugar, as the response) was not significantly different (P = 0.05) when Z. mobilis performance was compared in hydrolyzed and nonhydrolyzed extract. The maximum ethanol of 0.34 ± 0.02 g g(-1) initial sugar was obtained at 30°C, initial pH 5.2, and 80 rpm, using concentrations (g per 50 mL culture media) of: inoculum bacterial dry weight, 0.017; initial sugar, 5.78; peptone, 0.43; yeast extract, 0.43; and culture time of 36 h.
Carob has been widely grown in the Mediterranean region for a long time. It has been regarded as only a forest tree and has been neglected for other economical benefits. However, in recent years, this fruit has gained attention for several applications. As petroleum has become depleted, renewable energy production has started to gain attention all over the world; including the production of ethanol from underutilized agricultural products such as carob. In this project, the optimum extraction conditions were determined for the carob fruit by using the response surface design method. The obtained extract was utilized for production of ethanol by using suspended Saccharomyces cerevisiae fermentation. The effect of various fermentation parameters such as pH, media content and inoculum size were evaluated for ethanol fermentation in carob extract. Also, in order to determine economically appropriate nitrogen sources, four different nitrogen sources were evaluated. The optimum extraction condition for carob extract was determined to be 80 degrees C, 2h in 1:4 dilution rate (fruit: water ratio) according to the result of response surface analysis (115.3g/L). When the fermentation with pH at 5.5 was applied, the final ethanol concentration and production rates were 42.6g/L and 3.37 g/L/h, respectively, which were higher than using an uncontrolled pH. Among inoculum sizes of 1%, 3%, and 5%, 3% was determined as the best inoculum size. The maximum production rate and final ethanol concentration were 3.48 g/L/h and 44.51%, respectively, with an alternative nitrogen source of meat-bone meal. Overall, this study suggested that carob extract can be utilized for production of ethanol in order to meet the demands of renewable energy.
At first some general considerations about specificity and characteristics of SSF, their advantages and disadvantages as compared to LSF, are presented. Microorganisms involved in solid substrate fermentations are identified, considering the better performances of filamentous fungi. The solid substrates and their basic macromolecular compounds are detailed in relation to this complex and heterogeneous system. Biomass measurement is examined in detail, as well as environmental factors, both essential for studying and optimising solid substrate fermentations.
Biomass feedstock having less competition with food crops are desirable for bio-ethanol production and such resources may not be localized geographically. A distributed production strategy is therefore more suitable for feedstock like water hyacinth with a decentralized availability. In this study, we have demonstrated the suitability of this feedstock for production of fermentable sugars using cellulases produced on site. Testing of acid and alkali pretreatment methods indicated that alkali pretreatment was more efficient in making the sample susceptible to enzyme hydrolysis. Cellulase and beta-glucosidase loading and the effect of surfactants were studied and optimized to improve saccharification. Redesigning of enzyme blends resulted in an improvement of saccharification from 57% to 71%. A crude trial on fermentation of the enzymatic hydrolysate using the common baker's yeast Saccharomyces cerevisiae yielded an ethanol concentration of 4.4 g/L.