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Cyanobacterial biodiversity and potential applications in biotechnology
Abstract
Cyanobacteria (also known as blue-green algae) are a group of extraordinari ly diverse Gram-negative pro- karyotes that originated 3.5 billion years ago. Their dive r- sity ranges from unicellular to multicellular , coccoid to branched filaments, nearly colourless to intensely pi g- mented, autotrophic to heterotrophic , psychr ophilic to thermophilic, acidophilic to alkylophilic, planktonic to barophilic, freshwater to marine including hyper- saline (salt pans). They are found both free living and as endosymbionts. They are considered to be one of the potential organisms which can be useful to mankind in various ways. A number of important advances have occurred in cyanobacterial biotechnology in the recent years. World wide attention is drawn towards cyano- bacteria for their possible use in maricu lture, food, feed, fuel, fertilizer, colourant, pr oduction of various secondary metabolites including vitamins, toxins, e n- zymes, pharmaceuticals, pharmacological probes and pollution abatement. Only a few cyanobacterial strains (including Spirulina) have been well-characterized or exploited commercially. Basic research is needed to ide n- tify new cyanobacterial strains of high value products, strain improvement using molecular tools for rapid growth rate, ability to withstand varied environmental conditions and enhancement of synthesis of high value products. This review is intended to focus on the bi o- diversity of cyanobacteria in various environments, recent application and new developments that are diver- sifying the directions for commercial exploitation.
... Among the phytoplankton microorganisms, the phylum Cyanobacteria is the most ancient, being one of the most versatile and ecologically successful groups, living in a variety of environments (Abed et al., 2009), including oceans, freshwater, soil, bare rocks, ice shelves, hot springs, and hypersaline to alkaline lakes. They can also grow in environments with high metal concentrations and low water availability, such as desert regions, by forming endolithic communities (Sanchez-Baracaldo et al., 2005;Thajuddin & Subramanian, 2005;Rastogi & Sinha, 2009). Among the numerous cyanobacteria species, we highlight Limnospira (= Arthrospira), also known commercially as Spirulina. ...
... Numerous studies of Limnospira fusiformis habitat have revealed that it is more commonly found in alkaline environments and can survive in a wide range of salinities (Kebede, 1997;Sudhir & Murthy, 2004;Thajuddin & Subramanian, 2005;Dadheech et al., 2010;Asulabh et al., 2012;Benavente-Valdés et al., 2016;Costa et al., 2016;Cellamare et al., 2018). Arthrospira was observed for the first time in Algeria in 1996 at Tamanrasset Pond in the Southern region of this country (Fox, 1996), and it was also found in Telamine Lake in Northwest Algeria, where the latter genus will be studied for the first time in this publication. ...
This study examines a new strain, Limnospira fusiformis TL03, isolated from Lake Telamine in northwest Algeria. The strain was morphologically identified using a light microscope and molecularly characterized using its 16S rRNA gene sequence. The effect of salinity on growth and photosynthetic pigments was studied using a spectrophotometric method; different sodium chloride concentrations (0, 5, 15, 30, 45, and 60 g/l) in blue-green medium (BG11) cultured uniformly as homogenized cell suspension were tested. A morphological examination confirmed that the isolated strain belonged to the Limnospira genus. It has trichome lengths ranging from 210-2027 µm, as well as pitch and coil diameters ranging from 30-137 µm and 20-60 µm, respectively. The data from the 16S rRNA gene sequence analysis confirmed that the isolated strain was Limnospira fusiformis TL03 with 100% sequence similarity to Limnospira fusiformis SAG 85.79. The results also indicate that this strain can grow at various salt concentrations, with the highest optical density values (1.58 ± 0.014 and 1.56 ± 0.003) obtained in cultures containing 15 g/L and 5 g/L NaCl, respectively.
Keywords:
Identification; Isolation; Limnospira fusiformis TL03; Salt stress; Tolerance
... Anabaena-Azolla for crops and bioenergy Explora: Environment and Resource with the external environment through pores. [27][28][29] The roots are adventitious and grow vertically inside the water. ...
... Representative members of both symbiotic and free-living species of cyanobacteria, such as Nostoc, Anabaena, Calothrix, Chlorogloeopsis, Cylindrospermum, Plectonema, Gloeothece, and Anabaenopsis, are capable of producing indole acetic acid. 14,28 Anabaena can also produce phytohormones such as auxins, gibberellin, and cytokinins, which play a major role in promoting plant growth. 2 Phosphate, a mineral necessary for improving plant growth and development, is the limiting nutrient doi: 10.36922/eer.7975 ...
Cyanobacteria are prokaryotic group of ancient, morphologically varied organisms that utilize oxygen for photosynthesis, contributing significantly to global carbon and nitrogen fixation while improving crop quality. With the rising population and increasing demand for food, advancing agricultural productivity is essential. Therefore, ongoing research is crucial for boosting crop development and increasing food output. According to previous studies, cyanobacteria are among the best sources for crop development and enhancement. In addition, the Azolla-Anabaena are environmentally significant organisms, as they can be used in bioremediation, the reclamation of infertile land, mosquito control, and the sustainable intensification of animal husbandry by serving as high-quality fodder. Furthermore, they play a role in bioenergy development, emphasizing bio-oil and biodiesel production. The applications of these cyanobacterial systems extend far beyond traditional agriculture, presenting opportunities for innovation in the bioenergy sector. This review provides in-depth information on the critical role of cyanobacteria in ecological restoration and socioeconomic improvement, offering valuable insights for advancing sustainable agricultural practices and renewable energy solutions. In addition, the review highlights broader applications of the Anabaena-azollae symbiosis in nitrogen fixation, plant growth, and animal feed, underscoring their multifaceted nature and vast potential for practical use.
... Using a red light-emitting diode as a light source for Spirulina cultivation has shown an increase in biomass production compared to the natural light source. It has also been reported that green-colored light-emitting diodes resulted in the least cell growth compared to red and yellow light-emitting diodes [10]. Recent research has reported a high biomass growth with moderate protein accumulation in Spirulina biomass when a white light-emitting diode was used as a light source. ...
... The temperature has a controlling effect on the growth of Spirulina. Negligible growth in Spirulina is observed when the temperature is below 25 °C and above 35 °C [10]. In the present study, the temperature was maintained at 28 °C ± 2 °C, which is the optimal temperature. ...
as human food. Spirulina, a potential feedstock for bioen-ergy production, is an appropriate source of high protein, carbohydrates, and lipids. Spirulina has a highly profiled chemical composition rich in protein. It contains essential amino acids, fatty acids, vitamins and pigments, carbohydrates , and lipids. These beneficial compounds in Spirulina biomass can be extracted and utilized as food supplements to meet the growing food demand for human consumption. Cyanobacterial pigments can be explored in various fields, including antioxidant, anti-inflammatory, and anti-obesity [5]. Light plays the most significant role in cultivating Spi-rulina; the pigments utilize energy from the light for pho-tosynthesis. In Spirulina culture, cyanobacterium uses photons from sunlight as the primary energy source to grow. Microalgae absorb photons from sunlight as the source of nutrients [6]. Wavelength and light intensity are vital for algal growth. The light source can stimulate the specific growth rate of Spirulina. Spirulina uses light energy during photosynthesis and converts it into chemical energy for its growth. Energy is stored during the day in the Spirulina
... The diversity and distribution of algae in paddy fields have been reported by numerous authors (Fritsch, 1907;Desikachary, 1970;Guru et al., 2013 andRay, 2015a,b). Cyanobacteria have been reported from varying altitudes, sea levels to hill ranges, temple ponds, and freshwater lakes in Kodaikanal, Ooty, and Yercaud (Thajuddin and Subramanian, 2005). Paddy cultivation in the state increased to 8,80,000 hectares in 1970-71 from 7,60,000 hectares in 1955-56 since the formation of Kerala State. ...
... This contributes to 15% of total algal communities in tropical areas and 2% in temperate zones. (Thajuddin and Subramanian, 2005). Waterlogged fields show the presence of nitrogen-fixing bacteria which includes species of Anabaena, Calothrix, Rivularia, Cylindrospermum, Aulosira, Gloeocapsa, Rivularia, Scytonema, Tolypothrix, Nostoc. ...
Algae form a large group of morphologically diverse micro flora inhabiting various agricultural fields. Their contribution to enhancing soil fertility is widely studied. The shrinking of arable land and an increase in anthropogenic activities raises the need for quality and quantity from existing crops. Biomagnification and destruction of natural micro flora caused by chemical fertilizers is a matter of serious concern. This stresses the need to reduce applications of chemical fertilizers and substitute them with better alternatives. An increase in agricultural productivity can be achieved in different ways which include preventing loss due to various stresses both biotic and abiotic, and ensuring the supply of nutrients and sufficient water supply. Microalgae play a vital role in nitrogen fixation thereby increasing the fertility in paddy fields. The uniqueness of the algal community in wetland paddy fields varies depending on the water quality, changes in monsoon seasons, crop stages, fallow, and other physicochemical factors. They show great potential in flood control, recharging water, groundwater conservation, bioremediation, and wastewater reclamation and carbon sequestration. Thus microalgae are gaining immense importance due to the presence of metabolites and essential compounds as substitutes for harmful chemical fertilizers, pesticides and growth-promoting compounds. The present study attempts to review the distribution of microalgae in paddy fields in India.
... This suggests an enhancement of structural immunity and a mitigation of the adverse effects of biotic stress on overall plant health. These results are consistent with those reported by Thajuddin and Subramanian [72], who found that Cyanobacteria like Mastigocladus are known for their ability to fix atmospheric nitrogen into a form that plants can use, such as ammonia or nitrate [73]. Moreover, Attia et al. [74] reported that algae can release plant nutrients such as N, P, and K and excrete vitamins, amino acids, and plant growth hormones, which could be the primary cause of the increase in plant development and crop output. ...
Current agricultural production relies heavily on synthetic pesticides, which can damage human beings and the environment. To maintain the availability of food for the world's rapidly expanding population, more environmentally friendly alternatives to chemical pesticides need to be developed. Microalgae contain several antimicrobial chemicals and are regarded as one of the most promising alternative sources of innovative biopesticides. In this work, Ulothrix subtilissima rabenhorst and Mastigocladus laminosus cohn ex kirchner, isolated from Egyptian soil, were utilized to fight Rhizoctonia solani (R. solani) root rot disease and stimulate Pepper's defense mechanisms and growth promotion tactics. The chemical components of the methanolic extract of Ulothrix and Mastigocladus were analyzed by GC–MS and contained several active compounds that exhibited variable efficiency against the pathogen in vitro. The filtrates of Ulothrix and Mastigocladus separately effectively reduced the severity of Rhizoctonia root rot disease by 40% and 17.5%, respectively. Additionally, these treatments increased plant defense responses by 52% and 79%, respectively, compared to the untreated infected plants. The use of microalgal extracts produced varying responses in terms of photosynthetic pigments, total carbohydrate content, and total protein of Rhizoctonia-infected plants. Accordingly, this work presents a promising insight into algal extracts that could effectively limit Rhizoctonia root rot disease and can be used as a natural product against R. solani infection.
... Cyanobacteria can absorb a wide range of nitrogen sources, including nitrate (NO 3 -), ammonium (NH 4 + ), nitrite (NO 2 -), and urea. Most cyanobacteria (including Arthrospira platensis, Fischerella sp., Nodularia sphaerocarpa, and Spirulina maxima) prefer nitrate concentrations ranging from 0.2 to 5.2 g/L (Thajuddin, Subramanian, 2005). ...
Phycoerythrin's (PEs) are highly valuable as an effective agent in inhibiting free radicals, anti-inflammatory and anti-cancer. PEs can be used as nutrient ingredients and natural dyes for food and cosmetics. Additionally, they hold potential as therapeutic agents for oxidative stress-induced diseases and serve as fluorescent markers in biomedical research. Therefore, the aim of this study is to optimize the BG-110 culture media for cultivated Allinostoc sp. 1 to obtain phycoerythrin with the highest antioxidant activity. For this purpose, cyanobacterial strain Aliinostoc sp. 1 was cultivated in autotrophic and mixotrophic culture media with different concentrations of nitrate, phosphate, glucose, and sucrose. In this study, the purity and antioxidant activity of the phycoerythrin, and the quantity of exopolysaccharides produced in each culture media, were measured. The results show that the highest and lowest purity and wavelength of phycoerythrin, as well as exopolysaccharide content, is obtained from mixotrophic media containing 2 g/L glucose and phototrophic media without nitrogen sources, respectively. However, different cultivation conditions did not have a significant effect on the concentration of phycoerythrin ( p > 0.05). An examination of antioxidant activity using the DPPH and FRAP methods over a thirty-day period at temperatures of 5 and 35 °C revealed that the highest antioxidant activity occurred in samples grown in mixotrophic media containing 2 g/L glucose at all-time points ( p < 0.05). The assessment of antioxidant activity using the ABTS method demonstrated that samples grown in mixotrophic culture media containing 2 and 5 g/L glucose exhibited the highest antioxidant activity. Furthermore, increasing the temperature from 5 to 35 °C significantly reduced the antioxidant activity of phycoerythrin. Therefore, it can be concluded that the production and purification of phycoerythrin extracted from the cyanobacterium Aliinostoc sp. 1 with the highest antioxidant activity, purity, biomass, and exopolysaccharide concentration will have the best efficiency in mixotrophic culture media.
... These organisms possess the unique ability to perform mutually compatible functions such as nitrogen fixation and photosynthesis. They can thrive in various environments, including extreme climatic conditions and in both oxic and anoxic environments (Whitton and Potts 2000;Thajuddin and Subramanian 2005). Among them, Scytonemataceae populations are particularly prominent and are commonly found on rock surfaces. ...
The Scytonemataceae is the only traditional cyanobacterial family that exhibits the false branching phenotype and includes ecologically significant species, making it particularly interesting from an ecologic as well as economic perspective. This family is characterized by its taxonomic diversity and widespread distribution. The current study focuses on the diversity of the Scytonemataceae family in the Wayanad district, located in the Western Ghats of Kerala. The Western Ghats is notable for its exceptionally high level of biological diversity and endemism. Additionally, this area is ecologically sensitive and serves as a site for the systematic elucidation of many species. The research found that Scytonemataceae are commonly found on rock surfaces in the Wayanad district. These species display a color range that varies from pale or olive green to light brownish-black. The species were characterized and identified based on various morphological features, including cell dimensions, color, shape, type of branching, sheath characteristics, and cell contents. A total of 19 species were recorded, with the dominant genus being Scytonema with 15 species. Brasilonema follows with 3 species, and Petalonema contributes to one species, all belonging to the order Nostocales. Notably, among the 19 species identified, 11 are new records for the cyanobacterial flora of the Western Ghats in India.
... Cyanobacteria are oxygen-evolving photosynthetic prokaryotes that are known to grow in extreme environments (Thajuddin and Subramanian 2005). Several reports have well documented the ability of cyanobacteria to oxidize oil components. ...
Organic compounds and pollutants from industries like oil refineries, such as total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbons (PAHs) are known to pose toxic effects to the environment by degrading the soil and water quality along with the deposition of heavy metals thereby causing a threat to the life forms existing in them. This pose of imbalance in the ecosystem calls for an exigent notice and effort regarding controlling it. Hydrocarbon sludge from Effluent Treatment Plant (ETP) is one such toxic effluent eluted from oil refineries, and that is yet to be reported for a biodegradation study. Among a huge number of physical and chemical techniques, bioremediation has been a much talked about measure but is not in the required scale of practice yet. The reason could be a lack of efficient standardization for environmental applications. Cyanobacteria being well-known for their ability to survive difficult environmental conditions efficiently and to adapt to a mixotrophic nature, makes them ideal for performing bioremediation at a large scale in the open environment. The study aimed to quantify this ability of cyanobacteria by assessing the TPH content of the treatment sample, Effluent Treatment plant (ETP) hydrocarbon sludge pre- and post-treatment using GC-FID. The study was designed to treat the sludge by cyanobacterial strains in a pre-determined lethal dose concentration and monitor the activity of enzymes vital for a basic degradation metabolism, in addition to the growth rates of the cultures. The figures obtained from the enzyme assays and the growth rates appeared to be collateral in the direction of it being a highly promising bioremediation approach that could be efficiently performed by increasing the scale of application. The chromatograms obtained from the GC-FID depicted significant reductions in the TPH content of the treated samples that strongly indicated the potential of the cyanobacterial cultures to bioremediate an oil- contaminated site or treat toxic effluents from oil refineries.
... However, unlike plants, cyanobacteria do not have chloroplasts and lack a defined nucleus, distinguishing them as bacteria [1][2][3]. In scientific research and biotechnology, cyanobacteria have also proven helpful because of their ability to produce a variety of valuable compounds, such as biofuels, pharmaceuticals, industrial chemicals, and biofertilizers, through genetic engineering and metabolic modifications [4][5][6][7][8][9]. ...
This work aimed to identify the influence of pH, molarity, w/v fraction, extraction time, agitation, and either a sodium (Na2HPO4·7H2O-NaH2PO4·H2O) or potassium buffer (K2HPO4-KH2PO4) used in the extraction of C-phycoerythrin (C-PE) from a thermotolerant strain of Potamosiphon sp. An experimental design (Minimum Run Resolution V Factorial Design) and a Central Composite Design (CCD) were used. According to the statistical results of the first design, the K-PO4 buffer, pH, molarity, and w/v fraction are vital factors that enhance the extractability of C-PE. The construction of a CCD design of the experiments suggests that the potassium phosphate buffer at pH 5.8, longer extraction times (50 min), and minimal extraction speed (1000 rpm) are ideal for maximizing C-PE concentration, while purity is unaffected by the design conditions. This optimization improves extraction yields and maintains the desired bright purple color of the phycobiliprotein.
... [19]; (5) a lessening of soil salinity [20]; (6) the hindrance of development in weeds [16]; and (7) an expansion in the phosphate level of soil because of the discharge of natural acids [21]. Various harvests, including lettuce, maize, sugarcane, bean stew, tomato, oats, grains, cotton, and radish have likewise been displayed to profit from cyanobacterial vaccination [22]. According to Malliga, the utilization of Anabaena azollae as a biofertilizer resulted in lignolysis and the production of phenolic compounds, which in turn led to abundant sporulation of the organism [23]. ...
Sustainable cultivation strategies is a prerequisite for algal biorefineries targeting on reducing water and energy footprint. Thus, in this study, spent waters from the air conditioning unit (SP1), the water purifier/RO unit (SP2) and from the condenser tube of distillation unit (SP3) was filtered, autoclaved and reused in combination with artificial seawater- f/2 (ASW) media for cultivating oleaginous diatoms, Chaetoceros gracilis and Thalassiosira weissflogii and examine its impact on the growth and lipid production. Both strains showed a sharp rise in cell numbers in the test culture setups supplemented with 50% SP1 than in the control. Biomass productivity and total lipid content was highest in 50% SP1 cultures of C.gracilis (0.045 g L−1 d−1; 14.8% DW) and in 100% SP2 and 100% SP3 culture of T.weissflogii (0.06 g L−1 d−1; 19.6% DW), respectively. Indeed, the results validate for the first time the strategy of recycling spent waters recovered from various laboratory and industrial appliances as an optimized media for cultivating diatom algae via a carbon neutral and cost-effective approach.
... [19]; (5) a lessening of soil salinity [20]; (6) the hindrance of development in weeds [16]; and (7) an expansion in the phosphate level of soil because of the discharge of natural acids [21]. Various harvests, including lettuce, maize, sugarcane, bean stew, tomato, oats, grains, cotton, and radish have likewise been displayed to profit from cyanobacterial vaccination [22]. According to Malliga, the utilization of Anabaena azollae as a biofertilizer resulted in lignolysis and the production of phenolic compounds, which in turn led to abundant sporulation of the organism [23]. ...
Ensuring our survival primarily hinges on nourishment, as it provides the energy essential for various metabolic functions within our bodies. In the current scenario, adopting sustainable practices is imperative to satisfy our demand for both quantity and quality of food. This approach facilitates meeting our dietary needs and promotes an eco-friendly, pollution-free environment. The implementation of algae involves the utilization of biofertilizers, which augment the nutrient content of the soil, leading to elevated crop productivity. Algae can be used as biofertilizers, which are reservoirs for nutrients, and blue-green algae (BGA) can fix atmospheric nitrogen in specialized heterocyst cells and play a vital role in plant growth and stimulation. Microalgae used as biofertilizers include Acutodesmus dimorphus, Spirulina platensis, Chlorella vulgaris, Oscillatoria angustissima, Scenedesmus dimorphus, Anabaena azolla, and Nostoc sp. This can help to boost the plant growth, enhance soil fertility, and even help to improve the soil's physical and chemical properties, maintain the soil's temperature, and regulate aeration. The review focuses on an in-depth exploration of the implementation of algae as biofertilizers, specifically BGA, emphasizing their profound impact on soil ecosystems and sustainable agricultural practices. Ultimately, the review highlights and promotes the importance of various algae as a solution to raising environmental issues caused by excessive agricultural fertilizers and resulting agricultural pollution.
... Cyanobacteria are morphologically diverse, photoautotrophic prokaryotes with a wide range of ecological distribution and tolerance (15). They have a prime role in the manufacturing of food, feed, fuel, fertiliser, fine chemicals and pharmaceuticals and their application in pollution control is now being widely studied (16,17). They perform as ecological indicators and acts as a good bioremediation agent (18). ...
Prokaryotic autotrophs have a key role in maintaining the sustainability of
nature. Their secondary metabolites and stored chemicals have wide utility
in human life. Cyanophytes, the primitive producers, can become a necessity
of the modern world as they have enormous unexplored features. Candida
albicans, an opportunistic pathogen having multidrug resistance, fallout
health concerns in human and animal hosts. This study focused on the
antibiofilm potential of Oscillatoria tenuis NTAPD 02, isolated from a
hydrocarbon-polluted area against the hyphal switching of Candida albicans.
Ethanolic extract of the algal sample, OEE, was taken to perform the biofilm
quantification test and CLSM studies to determine the antibiofilm potential
of Oscillatoria tenuis against Candida albicans. The MBIC for OEE was found
to be 30 μg/mL against C. albicans and also shows a 70.8% reduction of
fungal biofilm. The GC-MS and FTIR analysis illustrates the presence of
potent phenolic hydrocarbons having an anti-proliferative effect. OEE was
also found stress generative in C. elegans (500 μg/mL). The ROS generation in
the worms intensified by increased concentration of OEE. The study proves
that Oscillatoria tenuis, NTAPD 02, can be considered an anti-proliferative
alga against C. albicans invasions.
... In addition, they had a wide use in biotechnological industry and can be used as biofuel, food and biomarker. 19 Investigations on bioremediation using microalgae has been started earlier by Ryther et al, 16 Kuyucak and Volesky 6 and Romero Gonzalez et al. 14 Microalgae can also employ to accumulate contaminated heavy metals and their xenobiotic. 18 Hydrocarbons are complex compounds made of hydrogen and carbon. ...
Hydrocarbons had wide application in day to day life.
Their unscientific disposal may contaminate the land,
water resources and cause health issues to living
things. Microalgae can be used as agents for
bioremediation in various contaminants. Microalgae
isolated from the oil spill area was able to disintegrate
anthrone when cultured in lab conditions.
Molecular identification of the microalgae was done
using 28 S rRNA and acquired the GenBank accession
number of NTAPD 01. The total chlorophyll content
was studied with life longevity of algae in the
hydrocarbon substrate for 20 days. Converting the
functional group of hydrocarbons to a stable less
contaminative compound, the microalgae, NTAPD 01
proved as a capable alga in anthrone reduction. FTIR
and the GC-MS confirmed the shifting of functional
ketone group in the algae degraded hydrocarbon to
intermediate and degraded diones. The lipid
accumulation in NTAPD 01 was observed by Confocal
Laser Scanning Microscopy. The study highlights the
biodegradation of anthrone by NTAPD 01 in
ecofriendly way.
... The most basic type of photosynthetic microorganisms, cyanobacteria, have a significant potential for the generation of bioenergy as well as high-value food and pharmaceutical items (Thajuddin & Subramanian, 2005). Since it remains a difficult task, extensive research is being done to turn cyanobacterial lipid into a significant industrial process (Patnaik & Mallick, 2015). ...
This book provides comprehensive insights on existing technologies and up-to-date advances in the field of waste management and treatment using algal-based technologies via different approaches and systems.
Coverage includes: Process fundamentals of algae-based wastewater treatment, including metabolic modelling, algal species for resource recovery and algae/bacteria interactions.Critical insights on the status, major challenges and modern engineering solutions in microalgae-related wastewater treatment processes.Case studies for coculturing microalgae with methanotrophs for enhanced nutrient recovery from wastewater.Advanced ways for valorisation of algae-based processes by integrating them with other technologies such as anaerobic digestion, biogas upgradation and bioelectrochemical systems.Up-to-date information on modern biotechnological approaches for deriving value-added bioproducts and biopolymers from microalgae, including biofuels, pigments and nutraceuticals.
This is an essential textbook for both undergraduate and graduate students pursuing degrees in environmental sciences, technologies, or engineering. Additionally, the book is equally useful for a broad audience, including researchers, engineers, and policy makers interested in the field of algal systems for waste and wastewater management. The book is also tailored to be used as an advanced manual for practitioners and consultancies working in the field of wastewater treatment and resource recovery.
ISBN 9781789063530 (paperback)
ISBN 9781789063547 (eBook)
ISBN 9781789063554 (ePub)
... cyanobacteria are valuable in several ways like global aquatic primary biomass production (40%) and different biotechnological applications for food/ feed, drugs, biofertilizers, phycoremediation (bioremediation by algae/cyanobacteria), biofuel, etc. 1,2 Algae are phototrophic and do not require organic nutrient sources for their growth. However, a few are mixotrophic and can utilize both inorganic/organic nutrients in the presence/absence of sunlight. ...
bstract
Algae and cyanobacteria are alternative renewable sources of bioenergy. Appertaining to their fast growth and fewer nutrient requirements, round-the-year cultivation in barren lands with wastewater is considered suitable over other energy crops. With the growing demand for fuels in various sectors, bioenergy like biodiesel, bioalcohol, biohydrogen, methane, and bio-crude (product of pyrolysis/hydrothermal liquefaction) is derived from algae/cyanobacteria as a support to other energy sources. Phycoremediation or bioremediation by algae/cyanobacteria is one of the most effective biological wastewater treatment processes. Algae/cyanobacteria are cultivated in effluents with high inorganic/organic loads from different industries like poultry, slaughterhouses, paper, textile, distillery, “supercritical water gasification”, produced water (while extracting nonrenewable oil/gas) landfill leachate, etc. Biomass for bioenergy integrated with phycoremediation provides techno-economic effectiveness of practical commercialization and sustainable energy production. It contributes to climate change alleviation, reducing competition with crop irrigation, carbon, and water footprint. Phycoremediation is useful in bioenergy with carbon capture and storage based bioenergy production while reducing the water footprint. In the biorefinery approach, the recycled wastewater cultivation medium is further reused for developing biomass for biofuel and coproduct development like feed, pharmaceuticals, pigments, lubricants, biochar, polysaccharides, bioplastics, biofertilizers, etc. While “water recycling” is imperative to essentially reduce “blue water footprint,” the recycled medium also contains different growth promoters and inhibitors. Microalgae cultivation is related to sustainable development goals (SDGs) about the environment (water, land, biodiversity, greenhouse gases), economy (energy, investment, industrialization), and social base (awareness, education). Biofuels (1st/2nd/3rd/4th) from all generations provide clean energy (SDG 7). Also, biofuel generation using wastewater is directly related to SDG 6/7/12/13. Therefore, it is worthwhile to study the different aspects of phycoremediation in biomass production and reuse strategies of wastewater to reduce water footprint in relation to SDGs during bioenergy generation from algae/cyanobacteria.
... Spirulina platensis is a planktonic, filamentous cyanobacterium found in tropical and subtropic alkaline warm lakes (Castro et al., 2019;Papalia et al., 2019). Due to its fast growth and robust culture conditions, and richness in proteins, polyunsaturated fatty acids, essential amino acids, vitamins, and pigments (Thajuddin and Subramanian, 2005), S. platensis has been widely applied as foods, feeds, nutraceuticals, pharmaceuticals, and cosmeceuticals (Nethravathy et al., 2019;Tang et al., 2020;Pocha et al., 2022), and also been deemed as one of the most promising microalgae strains for wastewater treatment and carbon sequestration from flue gas (Almomani et al., 2019). Therefore, in order to realize the development of a green sustainable circular economy of microalgae (Azmi et al., 2021;Devadas et al., 2021;Lim et al., 2022), efficient cultivation of S. platensis with increasing biomass production, lower cost, and higher special nutrients is highly expected. ...
Light plays an important role in the photosynthesis and metabolic process of microalgae. However, how different light conditions regulate the biomass production and protein accumulation of microalgae is mostly unknown. In this study, the influence of different light conditions, including light colors, densities, and light:dark cycles on the cell growth and biochemical composition of Spirulina platensis was symmetrically characterized. Under different colored lights, S. platensis all shows an increase trend within the increased light intensity ranges; however, each showing different optimal light intensities. At the same light intensity, different colored lights show different growth rate of S. platensis following the sequence of red>white>green>yellow>blue. The maximum growth rate and protein accumulation were determined as 21.88 and 5.10 mg/(L·d) when illuminated under red LED. The energy efficiency of different light sources was calculated and ranked as red>white>blue≈green>yellow. Transcriptomic analysis suggests that red light can promote cell growth and protein accumulation by up-regulating genes related to photosynthesis, carbon fixation, and C-N metabolism pathways. This study provides a conducive and efficient way to promote biomass production and protein accumulation of S. platensis by regulating light conditions.
... The carotenoids and phycobiliproteins, characteristic of cyanobacteria have high commercial value. They are used as natural food colourants, as food additives to enhance the colour of the flesh of Salmonid fish and to improve the health and fertility of cattle (Thajuddin and Subramanian, 2005). Phormidium valderianum is an excellent source of phycocyanin, a blue natural colorant useful as a phycofluor in diagnostics (Anburaj, 2011). ...
Cyanobacteria have played a substantial role in the evolution of life by
creating an oxygenic atmosphere through the process of photosynthesis.
They have specific adaptive strategies to survive in extreme environments.
They are ubiquitous in nature and can be spotted in both marine and
freshwater ecosystems and are especially rich in oligotrophic waters of the
tropical and subtropical marine environment. Cyanobacteria in the
mangrove ecosystem provide fixed nitrogen, carbon, bioremediation and
secreting plant growth-promoting substances etc, to the vegetation.
Diversity of cyanobacteria in this biome has been traditionally
underestimated. Cyanobacteria still play a significant role in modern coral
reef ecosystems by forming a major portion of epiphytic, epilithic, and
endolithic communities as well as of microbial mats. Cyanobacteria have
gained a lot of attention in recent years because of their potential
applications in the field of biotechnology. A wide range of secondary
metabolites exhibiting pharmacodynamic properties such as antibacterial,
antiviral, antifungal, anti-inflammatory and anticancer have been exhibited.
In addition to these applications, cyanobacteria are also used in
aquaculture, treatment of wastewater, food, fertilizers, vitamins, toxins,
enzymes and pharmaceuticals. We present an overview of the literature
describing the presence of cyanobacteria in marine and mangrove ecosystem
and uses of these in various industries which provide an outlook on the
challenges and future prospects of the field of cyanobacterial biotechnology.
Future research should focus on isolating new cyanobacterial strains from mangrove vegetation producing high value products and genetically
modifying existing strains to ensure maximum production of the desired
products.
... This is because there is a lot of readily available organic matter, which is very beneficial to succeeding crops (Dhar et al. 2007;Prasanna et al. 2003). Barley, oats, tomato, radish, cotton, sugarcane, maize, chilli peppers, and lettuce are only some of the crops that have been grown with the help of these biofertilizers (Thajuddin and Subramanian, 2005). ...
The overuse of chemical fertilisers has devastating effects on agricultural systems and the environment.
Thus, environmentally friendly substitutes for chemical fertilisers are needed. The potential contribution
of biofertilizer to food security and environmentally sound practises has increased its profile in
the agricultural sector. Soil fertility may be improved by the use of biofertilizers, which contain
microorganisms like fungus, bacteria, and protozoa that can fix nitrogen, dissolve phosphorus, and
sequester iron. Biofertilizers are made up of microorganisms that are both living and dormant and supply
nutrients for plant development. Nitrogen-fixing microbes, phosphorus-mobilising and phosphorus�solubilizing microbes, potassium-solubilizing microbes, blue-green algae, and azolla were just some of
the biofertilizers discussed in this review, along with their applications in crop production, production
processes, and examples of helpful microbes used in biofertilizer industries.
The increasing global demand for vegetables necessitates the development of sustainable agricultural practices that enhance crop productivity while minimizing environmental impact. Biofertilizers, comprising a diverse group of beneficial microorganisms, emerge as a promising solution to address these challenges. The use of biofertilizers will be crucial to enhancing the availability of vegetable crops in the upcoming years. In today's vegetable production, biofertilizers are being regarded as a substitute for chemical fertilizers. Biofertilizers promote plant growth and development and have the potential to increase crop yields. Its improved nutrient uptake, root development and overall plant health contribute to higher productivity in vegetable production. Incorporating biofertilizers into vegetable production requires careful consideration of factors such as soil conditions, crop type, and local climate. The environmental sustainability of biofertilizer use emphasizes reduced dependency on synthetic fertilizers, minimized environmental pollution, and their compatibility with organic farming practices. Overall, the use of biofertilizers represents a sustainable and environmentally conscious approach to vegetable production, supporting both agricultural productivity and long-term soil health.
The present work was conducted to check the effects of Zn exposure (10 - 100 µM) in the cyanobacterium Anabaena variabilis MEGCH1 over a period of seven days. The Zn concentration, even the lowest limit considered for the study, was substantially higher than that is generally found in coal mine contaminated wastewater. Most biochemical parameters in the organism showed marked tolerance towards Zn exposure up to a concentration of ~ 30 µM, although, in the presence of a higher Zn concentration, the organism showed substantial changes in its biomass, morphology, and ultrastructure, indicating the toxic nature of chronic Zn exposure. Similar toxicity was also evident in the entire C-fixation machinery, including the photosynthetic pigments, rate of photosynthetic and respiratory electron transport chain activities, and total carbohydrate content. There were negative impacts recorded on the heterocysts’ frequency as well as on nitrogenase and glutamine synthetase enzyme activities that resulted in poor nitrogen fixation and assimilation. Consequently, the level of soluble protein content within the cells was also reduced. These adverse effects were reflected in an obvious decrease in total biomass production. The increase in the total proline content of the treated culture clearly indicated that the organism was under obvious stress under Zn exposure. The cyanobacterium's survival and performance, however, in the presence of significant Zn ions in its surroundings, indicated that the organism could be considered for bioremediation technologies.
Cyanobacteria are increasingly being used as biofertilizers due to their numerous benefits for sustainable agriculture and ecological restoration. However, sunlight penetration is impeded and hypoxic and anoxic conditions are created by harmful algal blooms (HABs) in freshwater, which are mostly produced by cyanobacteria. The growing population and the simultaneous draining of energy resources present significant challenges to both the environment and the sustainable management of essential resources like agricultural products. The application of cyanobacteria as biofertilizer is said to be the most promising eco-friendly method. The prokaryotic creature that has evolved to be the most resilient and successful is the cyanobacterium. Cyanobacteria are becoming more and more popular as efficient solar energy conversion microorganisms. This biological mechanism generates oxygen. This review explores the methods of synthesis and applications of cyanobacteria as nanobiofertilizers, with a particular emphasis on their use in agriculture and industry.
Phycobiliproteins (PBP) are naturally occurring water-soluble fluorescent pigments produced by cyanobacteria, eukaryotic algae, and cryptomonads. These serve as accessory pigments for photosynthetic light harvesting complex. PBP are organized in supramolecular complex structures called as phycobilisomes which are assembled in a regular array on the outer surface of thylakoid membrane and lie adjacent to photosynthetic reaction center of PS-II in cyanobacteria and red algae. Depending upon the absorption maxima, these pigments are classified as phycoerythrin (λmax 540–570 nm), phycocyanin (λmax 590–630 nm), and allophycocyanin (λmax 620–655 nm). Being non-toxic and non-carcinogenic in nature, these can be safely used as coloring agents in food and cosmetics. These pigments have also been reported to exhibit a variety of pharmacological properties such as antioxidant, anti-inflammatory, neuroprotective, and hepatoprotective effect. Cyanobacterial species such as Anabaena sp., Gloeotrichia natans, Nostoc sp., Spirulina platensis, Spirulina fusiformis have been reported to produce PBP in significant amounts. Out of these, Spirulina platensis has been employed for commercial production of PBP. Since cyanobacteria are cosmopolitan in nature and grow in varied and extreme habitats such as hot water springs, cold deserts, acidic and alkaline conditions, thus, methods for extraction and purification of PBP produced by different cyanobacteria and red algae growing in various habitats have been presented in this chapter.
The present chapter encapsulates interactions of soil algae with various microbes. The nature and benefits of algae-microbial interactions are discussed briefly. The advantages and applications of algae-microbes mutual synergism are emphasized in this chapter. The interaction between soil algae-microorganism-plants resulted in the availability of nutrients, conditioning of soil, biofertilizers for plants, and improved crop production and plant defensive metabolites and pigments. The roles of microbial interaction with soil algae are to maintain soil fertilization and reduce the use of chemical fertilizers and pollutants in the soil. The chapter is intended to provide an overview of the benefits arising out of soil algae-microorganism-plants interaction.
Aim: This is an established fact that thermophilic cyanobacteria typically thrive in sulfur-rich thermal springs, while mesophilic cyanobacteria have an optimal growth temperature range of 28°C to 37°C. The objective of this study was to investigate whether mesophilic cyanobacteria can grow at elevated temperatures in the presence of sulfide. Additionally, the study aimed to explore the role of sulfide in mitigating thermal stress in mesophilic cyanobacteria. Research Methodology: Randomly isolated mesophilic cyanobacteria from rice fields of Patiala (India) were tested for their tolerance to thermal stress. Out of those, Geitlerinema acutissimum was able to grow at 42 °C, though the growth was less than at 28°C. Further the growth of the mesophilic Geitlerinema acutissimum was examined both at its optimal growth temperature and under thermal stress, with and without the presence of sulfide. In parallel, the levels of enzymatic antioxidants were assessed under these conditions. The tolerance of Geitlerinema acutissimum to sulfide was evaluated by growing the organism in varying concentrations (0.5 to 5 mM) of sodium sulfide. It was found that the addition of 2.5 mM sulfide to cultures at 42°C alleviated the negative effects of thermal stress. The levels of enzymatic (SOD, POD, and CAT) antioxidants were measured in the test organism grown under thermal stress with and without sulfide. The incorporation of 2.5 mM and 0.5 mM sulphide, respectively in culture of mesophilic and thermophilic cyanobacteria enhanced these parameters under thermal stress with more pronounced effect in Geitlerinema acutissimum . These results indicated the protective role of sulphide on these parameters. The activities of superoxide dismutase, peroxidase and catalase levels increased in presence of sulphide under thermal stress. Result and conclusion: These results indicated the operation of enzymatic defense system in Geitlerinema acutissimum to counter effect of thermal stress. The present study suggested that during thermal stress reactive oxygen species were produced, but Sulphide appears to be a signal molecule under thermal stress to enhance levels of enzymatic antioxidants. Whether this mechanism applies to other mesophilic cyanobacteria can be further explored by studying additional strains. The organism exhibited reduced growth accompanied by an increase in antioxidants such as SOD, POD, and CAT. This study is the first to report the role of sulfide in mitigating thermal stress in Geitlerinema acutissimum, through activation of enzymatic antioxidant defense mechanisms.
Microalgae have become a novel, fascinating, and profitable platform for the synthesis of various biomolecules. These biomolecules include proteins, lipids, and carotenoids, which are already approved for commercial applications. The main goal of the developmental process is to enhance the biomolecule yield and microalgal biomass multiplication rate. Over the past few decades, there has been a significant advancement in the technology of microalgae and cyanobacterial genetic engineering. The results of the studies have contributed an elevation in the commercial viability of microalgal products. We describe a protocol to genetically modify the genome of the freshwater microalgae Chlorella vulgaris which possess abundant protein content transformation with a viral vector for the biopharmaceutical manifestation with the help of human basic fibroblast growth factor (bFGF) & SARS-CoV-2 receptor binding domain (SARS-CoV-2 RBD).
It is well-recognized that thermophilic cyanobacteria flourish in sulfur-rich thermal springs. Mesophilic cyanobacteria are available at temperatures ranging from 28 to 37°C. This study sought to determine if mesophilic cyanobacteria can also grow at elevated temperatures in the presence of sulphide, and if yes ,then what role sulfide would have in reducing high temperature stress in mesophilic cyanobacterial organisms. The prolifecation of Nostoc ellipososporum, a mesophilic cyanobacterium, was examined at its optimal temperature, both in the presence and absence of sulphide under thermal stress. During the current investigation, nitrate uptake was seen to slow down under temperature stress, but when sulphide was added to the cultures, nitrate uptake increased. This demonstrates that increased levels of nitrogen metabolism in the presence of sulphide contributed to the survival of the test organism under temperature stress.
Microalgae represent all photosynthetic prokaryotic and eukaryotic microorganisms. Cyanobacteria, previously known as blue-green algae, are prokaryotic, not eukaryotic like other algal groups. Since they are photosynthetic, their production systems are the same as those of microalgae. Microalgae and cyanobacteria form phytoplankton. Since they are used as nutrients for fish and other aquatic organisms, they form the starting point of the food chain in nature. As a result of increasing environmental sensitivities, developments in treatment technologies continue. Because the excess nitrogen, phosphorus, and other nutrients in wastewater that are left in the receiving environment without treatment cause eutrophication and harm the environment. Wastewater containing abundant mineral substances can be a suitable development environment for aquatic plants, microalgae, and cyanobacteria (blue-green algae) if environmental conditions such as light and temperature are regulated. With this type of treatment process, wastewater is treated, and new products can be commercialized. Biomass is obtained by growing microalgae in wastewater. In addition to its use in environmental biotechnology applications such as biofuel, biojet fuel, biofertilizer, and animal feed production, it also finds use in medicine, food, pharmacy, textiles, and cosmetic technologies. While feeding microalgae with wastewater contributes economically to increasing the efficiency of treatment, such wastewater treatment systems, which can generate income by producing microalgae cultures, have become an important option. Feeding microalgae with wastewater not only contributes economically to increasing the efficiency of treatment but also has become an important option for this purpose among such wastewater treatment technologies that generate income by producing microalgae cultures.
So, the main purpose of this book chapter is to examine in all detail the studies in the literature on the conversion of cyanobacteria in the microalgae-bacterial biomass-based system into either an energy source or soil-improving fertilizer and commercialization while removing pollutants from domestic wastewater. In this sense, this chapter first reviews the recent developments in microalgae-cyanobacteria-based systems for wastewater pollution control, then discusses the biosorption and bioaccumulation mechanisms of pollutants by cyanobacteria, factors affecting microalgae-cyanobacteria systems and developments and innovative designs on photobioreactors. Finally, the removal efficiency of pollutants from wastewaters by microalgae, which is widely found in receiving waters such as lakes or river flora, was evaluated within the scope of a case study carried out in the literature. According to the case study results, microalgal-cyanobacteria-based technology was assessed in terms of both an effective and low-cost advanced treatment of municipal wastewater and also an alternative energy source or soil-improving fertilizer usage after harvest as biomass-based.
The increasing global demand for food has led agricultural crop producers to rely heavily on the use of chemical fertilizers to enhance production yields. However, the unregulated use of these chemicals has resulted in negative consequences for both human health and soil fertility. Biofertilizers have emerged as an alternative to these chemicals. Microbial inoculants used as biofertilizers and biopesticides have proven to be effective and environment-friendly approaches towards sustainable agriculture, without causing any known adverse effects or pollution. Recently, concerns have been raised regarding the impact of climate change on the beneficial traits of these bio-inoculants in nature. In order to preserve and more efficiently utilize plant-associated beneficial microbes, genetic tools have been employed to modify them and prevent them from altering their essential phenotypes. In this chapter, we have evaluated various genera of microbes that are useful in crop production, as well as genetic approaches to enhance their efficiency. The use of genetic engineering and nanotechnologies has been shown to yield precise benefits to agriculture and has therefore been discussed in the context of the benefits associated with microbes in agriculture. Furthermore, strategies have been elaborated upon to expand the production of bio-inoculants from their current bottleneck status in laboratory research to large-scale industrial production, with challenges for routine agricultural application.
The economically important Cyanobacterial genus Limnospira is commercially utilized as a dietary supplement and nutraceutical agent. We present the whole-genome sequence of Limnospira fusiformis NRMCF6962 and was isolated from Kondakarla Ava Lake of Visakhapatnam, Andhra Pradesh, India.
Phytoplankton and zooplankton play an important role in fresh and marine ecosystems because of their significant contribution in aquatic food chain as primary and secondary producers. Nearly half of all primary and oxygen production worldwide is made up of phytoplankton. Phytoplankton also significantly accelerates biogeochemical cycles and nutrient (re)cycling in both terrestrial and aquatic ecosystems. Because they are a rich supply of vitamins, essential fatty acids, carbohydrates, proteins, pigments, and biologically active primary and secondary metabolites, plankton have taken on a great deal of significance in the field of biotechnology in recent years. The plankton community is one of the most promising sources for novel products due to its vast biodiversity. Microalgae biotechnology has recently been able to satisfy the high demands of the food and pharmaceutical industries.
Cyanobacteria are regarded as vital constituents of aquatic ecosystems which recently become viable option for bioremediation since it can remove contaminants from polluted water. They possess intriguing metabolic properties and exhibit differential growth patterns. This study elucidates the isolation and identification of two marine and two freshwater indigenous Oscillatoria spp., their growth performance, nutritional composition along with intricate biochemical profiles. Agar streak plate method was used for the isolation, growth curve was determined through chlorophyll content and optical density. Freshwater and marine Oscillatoria spp. were mass cultured in commercial Bold Basal Media and Conway media respectively. Wet biomass was harvested through centrifugation at the early stationary phase of their respective growth curve and oven-dried at 40 °C to determine the nutritional and biochemical profiles. Oscillatoria sp. 2 displayed significantly higher (p ˂ 0.05) chlorophyll-a (22.72 ± 0.04 µg/mL) and OD value (1.87 ± 0.03) in the stationary phase (9th to 11th day) than the other species. Crude protein contents (%) varied from 21.56 ± 0.09 to 56.97 ± 0.03. Crude lipid (%) ranged from 9.07 ± 0.07 to 17.13 ± 0.13 and Crude fiber content (%) showed the range from 7.49 ± 0.15 to 17.04 ± 0.08. Fatty acid and amino acid were also found variable among the species. Present study will contribute to the meticulous selection and characterization of Oscillatoria sp. to utilize it in the rigorous scientific investigations and diverse commercial applications.
Cyanobacteria, as ancient photosynthetic prokaryotes, have garnered attention due to their ability to produce an array of biologically active metabolites, including alkaloids, terpenoids, polysaccharides, pigments, cyclic peptides, phenols, lipids, and vitamins. The diverse morphological, physiological, and genetic traits of cyanobacteria contribute to the synthesis of these compounds, which possess promising medicinal properties, excellent abilities for bioremediation, and potential to be used as nutraceuticals, biofertilizers, cosmetics, nanomaterials, and biofuels. This chapter provides a deeper insight into the extraction techniques employed to obtain these bioactive compounds from cyanobacteria, encompassing both traditional and innovative methods. Furthermore, the synthesis pathways and genetic manipulation of cyanobacteria are explored, focusing on enhancing the quality and quantity of bioactive compounds through genetic engineering approaches. The applications of cyanobacterial bioactive compounds are extensive, with a particular emphasis on their utilization in drug discovery and development. The potential therapeutic uses, such as antiviral, anti-tumor, antibacterial, anti-HIV, and food additives, are discussed, showcasing the established roles of cyanobacterial compounds in various fields. Additionally, the chapter highlights the emerging trends in the application of cyanobacterial compounds in nanobiotechnology, with a focus on their incorporation into nanoconjugates and nanomaterials for advanced drug delivery systems and biomedical applications. This comprehensive chapter provides valuable insights into the synthesis, extraction, and applications of cyanobacterial bioactive compounds, contributing to the growing body of knowledge in the field of natural product research and pharmaceutical development.
The unidentified geochemical and physiochemical characteristics of Soda Lakes across the globe make it a novel reservoir and bring attention to scientific civic for its conceivable industrial and pharmaceutical applications. In India, in the Maharashtra state, Lonar Lake is a naturally created Soda Lake by a meteorite impact. Phylogenetic data from this lake explored a diverse array of microorganisms like haloalkaliphilic bacteria and Archaea. Previously reported studies postulated the major microbial communities present in this lake ecosystem are Proteobacteria, Actinobacteria, Firmicutes, and Cyanobacteria. Furthermore, it also contains Bacteroidetes, Nitrospirae, and Verrucomicrobia. This lake is also rich in phytoplankton, with the predominant presence of the Spirulina plantensis. Unique microbial strains from Lonar Lake ecosystems have fascinated consideration as a source of biological molecules with medicinal, industrial, and biotechnological potential. Recent literature revealed the isolation of antibioticproducing bacteria and alkaline proteases-producing alkaliphilic bacterium, as well as novel species of rare methylotrophs, other bacterial strains involved in producing vital enzymes, and unique actinomycetes are also reported. It indicates that the novel bacterial assemblage not reached hitherto may exist in this modified and unique ecology. This comprehensive review provides information about microbial diversity and its industrial and pharmaceutical interests that exist in Lonar Lake, which could be the future source of bioactive enzymes, biosurfactants, and biofuel and also useful in bioremediation. Furthermore, the novel species of microorganisms isolated from Lonar Lake have applications in the biosynthesis of medicines like antibiotics, antivirals, antifungals, anti-inflammatory agents, and precursors for synthesising valuable products. Data consolidated in the present review will cater to the needs of emerging industrial sectors for their commercial and therapeutic applications.
Antibiotic resistance of bacteria is causing clinical and public health concerns that are challenging to treat. Infections are
becoming more common in the present era, and patients admitted to hospitals often have drug-resistant bacteria that can
spread nosocomial infections. Urinary tract infections (UTIs) are among the most common infectious diseases afecting all
age groups. There has been an increase in the proportion of bacteria that are resistant to multiple drugs. Herein is a comprehensive update on UTI-associated diseases: cystitis, urethritis, acute urethral syndrome, pyelonephritis, and recurrent
UTIs. Further emphasis on the global statistical incidence and recent advancement of the role of natural products in treating
notorious infections are described. This updated compendium will inspire the development of novel phycocompounds as
the prospective antibacterial candidate.
Plant-derived bioactive chemicals are gaining popularity because of their safe nature and numerous medicinal applications. The prolific and diverse ecosystem of mangroves is one of the rich sources of phytochemicals, which are important in the field of natural product-based therapies. In this chapter, we have tried to provide an informative sketch of the research ongoing in the field of cancer therapy using mangrove-based phytochemicals. The bioactive secondary metabolites obtained from different mangrove species are elaborately studied in terms of their anticancer potential. Specific studies related to application of these compounds in different cell lines of cancer are found to be scanty and scarce. Still, an attempt is made to highlight the effect of these compounds in cell cycle at different stages of malignancy. To analyze the current research trend in terms of contribution in this field from all over the world, a bibliometric analysis has been conducted. Researchers appear to be focusing on secondary metabolites as a potential source of anticancer chemicals, as evidenced by the network map. Overall, this chapter will provide an insight into the developing research based on mangrove-derived phytochemicals and the potential application in cancer therapy.
El presente trabajo colectó, aisló, identificó y caracterizó el potencial antimicrobiano de dos especies filamentosas de cianobacterias de la Amazonia colombiana. Se utilizaron técnicas microbianas de rayado en medio sólido y dilución para obtener las cepas con una sola especie. La identificación se realizó por caracteres morfológicos y secuenciado de la sección conservada Cya de gen 16s. Se identificaron por reacción en cadena de la polimerasa (PCR) la presencia de genes que secuencian policétidos sintasas (PKS) y péptidos no ribosomales sintetasas (NRPS) asociados a rutas productoras de metabolitos secundarios. Se evaluó la actividad antimicrobiana de extractos polares y no polares con una batería Gram positiva, dos Gram negativas y una cepa fúngica. Se identificó la cepa 5 como Limnothrix vacuolifera (Skuja) Komárek y la cepa 9 como Lymnothix planktonica (Wołoszyńska) Meffert. En las dos cepas se encontraron PKS y NRPS. Finalmente, los extractos polares inhibieron el crecimiento de Enterococcus faecalis, Escherichia coli y Klebsiella pneumoniae y una cepa Penicillium sp. Los extractos no polares no mostraron actividad antimicrobiana. Es el primer registro de estas para la Amazonia colombiana y el primer registro de actividad antibiótica de cianobacterias continentales colombianas.
Different types of microorganisms are known to exist in freshwater habitats. These microbes function similarly to the microorganisms found in soil and air. Freshwater, brackish, marine and terrestrial cyanobacteria (blue–green algae [BGA]) are a diverse group of prokaryotes and are also the most successful and oldest life forms on the planet. They play an important role in maintaining and improving soil fertility, increasing plant growth and yield as a natural biofertilisers, nutrient cycling, nitrogen (N2) fixation and environmental protection. Cyanobacteria demonstrate the potential for effectively converting light energy into chemical energy. The aim of this chapter is to provide valuable information about the potential role of freshwater cyanobacteria in solving the agricultural and environmental problems on the planet earth.
Most of these articles are either the first attempt to establish a base line data on carbon storage potential of mangroves or approaches to synthesize the results of numerous previously published articles on the subject. Based on an extensive review and meta-analysis of data on carbon stock and sequestration in context of climate change, we present here a list of publications, which may act as a pathfinder for future researchers who want to pursue their researches linking climate change and carbon sequestration by mangroves. In the present bibliographic section, many of the published literature could not be properly placed on the shelf and these may be considered as unintentional faults of the present authors for which we deeply apologize.
In modern-day agricultural practices, the application of microbes as biofertilizers is considered an important component of sustainable organic farming and ecofriendly practices, so biofertilizers are used instead of chemical fertilizers that cause environmental pollution, which severely affects human health. Microorganisms like plant growth–promoting rhizobacteria (PGPR), fungi, algae, etc., have also shown biofertilizer-like exertion in modern agronomic practices. These microbes live in the rhizosphere and have the movability to invade plant roots and enhance their development. Microbes’ positive impacts are achieved through various mechanisms, such as phosphorus solubilization, nitrogen fixation, plant nutrient and phytohormone development, antimetabolites to sustain root growth, pathogen defense, and recovery from stressful environmental conditions. This is the key reason why many microbes are increasingly being used. The goal of this review is to focus on the importance of microbial fertilizers and their advantageous effects on plants in promoting sustainable agriculture.KeywordsMicrobesBiofertilizersSustainable agriculture
Terrestrial algae have been studied at widespread Antarctic localities. However, their diversity is not fully known as often collections have not been made from all habitats and techniques have been inadequate for recognition of the total flora. Identifications can be unreliable and are often left at generic level. Despite this it seems that they largely comprise cosmopolitan species but at a reduced diversity relative to other regions. There is a small element of endemic species which, in general, differ only slightly from related species elsewhere. Lack of base-line taxonomic knowledge, detailed characterization of environmental factors, and application of multivariate analysis restricts our ability to define communities and interpret their distribution patterns. Examples are provided where understanding would be greatly improved by more detailed analyses. Dispersal barriers could be operating both to and within Antarctica. However, local dispersal by wind seems readily accomplished. Overcoming dispersal barriers to Antarctica, and between ice-free localities within Antarctica, could present a greater problem. Investigation of long-distance transport of propagules by wind, birds and humans is needed.
Pollution control through bioremediation is the most economical and ecofriendly approach. Using oxygen evolving microalgae in general and cyanobacteria in particular would be advantageous in many ways. Most gaseous and liquid pollutants are metabolized by cyanobacteria fairly rapidly bringing down their levels in the atmosphere and effluents. A number of toxic compounds such as phenolics, pesticides and antibiotics as well as recalcitrant chemicals such as lignin can be degraded and detoxified by them. Various metals including the heavy metals can be removed and even recovered from effluents by processes of bioaccumulation and biosorption by cyanobacteria.
Cyanobacteria (also known as blue-green algae) occur worldwide in a range of terrestrial, freshwater, and marine environments. This large and diverse group of Gram- negative prokaryotes, long employed for research on photosynthesis and nitrogen fixation, is now being utilized and further explored for biotechnological development. Cyanobacteria now find wide use in agriculture and hold great promise in the field of bioremediation. Various chemicals, including restriction enzymes, pharmacological probes, and labelled compounds for research, as well as fluorescent probes for clinical diagnostics, are now commercially available. Potentially useful compounds, including pharmaceuticals and industrial chemicals, have been identified and are currently being developed. Cyanobacterial hydrogen production, still in the basic research stage, promises production of a low-cost, non-polluting energy source for the next century. Low-cost culture methodology and improvements in downstream processing are needed to make industrial-scale cyanobacterial biotechnology a reality.
An axenic laboratory isolate of a heterocystous cyanobacterium Anabaena azollae ML2 exhibited lignolysis and showed polyphenol oxidase and laccase enzyme activities. The ethylene released from α-keto-γ-methylthiolbutyric acid substrate estimated by gas chromatography was an indirect confirmation of the ligninase activity. The spectrophotometric absorbance peaks at 285 and 292 nm in the treated culture filtrates was additional evidence for the release of phenolics from the lignin of coir into the milieu. The invasion and profuse sporulation of the organism inside the coir matrix (solid waste) make the lignocellulosic coir waste an excellent, inexpensive carrier for the BGA biofertilizer.
The genome sizes of 128 strains of cyanobacteria, representative of all major taxonomic groups, lie in the range 1.6 x lo9 to 8.6 x lo9 daltons. The majority of unicellular cyano-bacteria contain genomes of 1.6 x lo9 to 2-7 x lo9 daltons, comparable in size to those of other bacteria, whereas most pleurocapsalean and filamentous strains possess larger genomes. The genome sizes are discontinuously distributed into four distinct groups which have means of 2.2 x lo9, 3-6 x lo9, 5.0 x lo9 and 7.4 x lo9 daltons. The data suggest that genome evolution in cyanobacteria occurred by a series of duplications of a small ancestral genome, and that the complex morphological organization characteristic of many cyano-bacteria may have arisen as a result of this process.
In the framework of a survey of the marine Cyanophyceae of Papua New Guinea, material was collected along the north coast (Madang Province) and the south coast (Central Province). Thirteen taxa belonging to the genera Borzia (2 taxa) and Oscillatoria (11 taxa) were recorded, especially in the infralittoral zone. All of them are new records for Papua New Guinea; nine of them, i. e. Borzia papuana, Oscillatoria bonnemaisonii var. minor, O. boryana var. marina, O. castanea, O. laetevirens var. papuana, O. laingii, O. olivaceobrunnea, O. olivaceobrunnea var. motuporensis, O. subuliformis var. major are new for science. The two Borzia species are endozoic, whereas the Oscillatoria taxa are epipsammic or epiphytic.
A preliminary survey was made of over 500 kilometers of the southern east coast of India starting from Nagore in the Bay of Bengal (19°50'N and 79°50’E) and ending at Cape Comorin in the Indian Ocean (8°5'N and 77°33/E) including Palk Strait, Palk Bay and the Gulf of Mannar. The survey of cyanobacteria in each region included different areas viz. open sea, stagnant sea water ponds and puddles, backwaters and salt pans. During the survey the nature of the sea shores in all the regions were examined and representative samples of sea water were taken from different regions for chemical analysis. The Gulf of Mahner region, with vast areas of rocky shores and nutrient rich water, showed the maximum cyanobacterial diversity. A total of 163 species from 48 genera belonging to 14 families of cyanobacteria were recorded in the survey. Thirty two species from 13 genera, all of which were non-heterocystous, were considered versatile, since they occurred in all areas in different regions. Amongst these, Phormidium tenue was the most versatile species because it occurred not only in all areas but also in all regions of the survey. An important observation revealing the remarkable adaptability of cyanobacteria was that 75 of the species recorded during the survey had been originally reported from freshwater sources by earlier workers. Another interesting observation was the total absence of heterocystous forms in hypersaline environments (salt pans).
A brief, preliminary survey of the algal community of the upper inter-tidal and lower maritime zone of a rocky shore was made in the spring of 1971 near Millport, Isle of Cumbrae, Scotland. The blue-green algae Gloeocapsa crepidinum Thur. ex Born. et Thur., Nostoc entophytum Born. et Flah., Lyngbya sp. and L. lutea [C. Ag. (Gom.)] Gom. were distributed vertically in such a way as to indicate a zonation pattern while two small green algae occurred infrequently and sporadically. All the algae investigated were embedded together in a more or less common mucilage matrix.
The Anthoceros punctatus-Nostoc and Blasia pusilla-Nostoc symbioses were investigated. In both associations the Nostoc colonies develop in mucilaginous cavities on the undersurface of the gametophyte. The sporophytes of Anthoceros have no Nostoc colonies; no sporophytes of Blasia were found. The symbiotic algae have been identified as Nostoc sphaericum ex. Born et Flah. The heterocyst frequency of the free-living isolates is 3–6% but this increases to 30% (Blasia) and 43% (Anthoceros) when the algae are growing symbiotically. On infecting alga-free gametophytes of Blasia pusilla with Nostoc, algal colonies develop in the cavities within 72 h. The developing Nostoc colonies stretch the cells of the cavity wall and there also arise from a point on the host cavity wall, usually opposite the cavity pore, septate, branched, filamentous protrusions, which increase the surface area of contact between phycobiont and host by about 30% within 4 weeks of colony formation. Such outgrowths may facilitate interchange of metabolites between the alga and liverwort. The Nostoc phycobiont of Anthoceros may infect Blasia and vice-versa. A strain of Nostoc punctiforme isolated from Gunnera also infects Blasia, but four other Nostoc isolates, including one from cycad root nodules, do not. Five other heterocystous algae, five non-heterocystous filamentous algae and one unicellular alga tested do not infect Blasia. The nitrogen contents of thalli with Nostoc colonies are significantly higher than those treated with algae which do not develop colonies. The symbiotic algae differ physiologically and biochemically from free-living algae. They show higher rates of nitrogenase activity (acetylene reduction assay), are depleted of nitrogen-storing phycobilin pigments and structured granules and although metabolically active do not evolve O2 or fix CO2 photosynthetically, but do have polyhedral bodies which contain the key CO2-fixing enzyme ribulose-l,5-diphosphate carboxylase. The Blasia symbiosis grows well and remains established in the pH range 4–8, at low levels of combined nitrogen (
The N2(C2H2) fixing activity was surveyed in lichens of diverse structure and habitat, all containing a blue-green phycobiont; twenty-six species from fourteen genera are reported for the first time to fix nitrogen. Rates of N2(C2H2) fixation showed great variability between different lichen samples.
The proportion of heterocysts, as the assumed site of N2 fixation, was estimated in all the above lichens together with fourteen additional species. In lichens with one phycobiont, heterocysts form about 4% of the total algal cell population; in those with two phycobionts the blue-green member is found in special structures and has a very high proportion of heterocysts, typically 20–30%; the N2(C2H2) activity appears to reflect this. The high proportion may be associated with the proximity of the green phycobiont.
Summary Two varieties of tomato (Pusa Rubi and Selection 120) positively responded to algal inoculation in terms of the yield of fruits and shoots, but there was no significant effect on the vitamin C content of the fruits. A combined application of urea and algae was more effective than the application of urea alone.
Biological nitrogen fixation is a characteristic of certain micro-organisms, which may be free-living or occur in symbiotic association with higher plants. The purpose of this paper is to summarize some of the biological and ecological aspects of nitrogen-fixation by free-living forms. Biochemical aspects have been reviewed in other contributions to this discussion by Drs Wilson, Burris, and Cox & Fay. Nitrogen fixation by heterotrophic micro-organisms has been considered by Jensen (1965); nitrogen fixation by blue-green algae by Fogg & Stewart (1965), and by Stewart (1966, 1969), while Moore (1966) has evaluated the contribution of nitrogen-fixing micro-organisms to soil fertility.
DURING a cytochemical study of nodule cells in Egyptian clover, Trifolium alexandrinum, it was observed that in addition to the rhizobial bacteria, a blue-green alga, identified as Nostoc punctiforme, occurred inside the nodules. So far as we are aware, blue-green algae have not been reported to be associated with nodule formation in legumes.
Nitrogenase reductase (Fe-protein) was detected in the marine planktonic cyanobacterium Trichodesmium. The molecular weight was about 38 kD, as shown by western blotting using anti -Rhodospirillum rubrum nitrogenase reductase antiserum. The enzyme was confined to a limited number (ca. 10–40%) of randomly distributed trichomes in the Trichodesmium colonies, as shown by immunogold localization and transmission electron microscopy. Associated microorganisms had little or no nitrogenase. Nitrogenase showed a diel cycle in localization: present throughout the cytoplasm of cells in N2-fixing (daytime) colonies but at the periphery of non-N2-fixing (nighttime) colonies. This structural arrangement of N2-fixing trichomes and nitrogenase is novel and different from the previously held paradigm for this and other diazotrophic cyanobacteria.
Wistar strain male albino rats were administered with the water soluble fraction of the ethanol extract of 12 different strains of marine cyanobacteria to understand their effect on the biochemical composition of the blood namely, serum levels of proteins, total free sugars, cholesterol, calcium, magnesium, sodium and potassium and the levels of activity of the enzymes glutamic pyruvic transaminase, glutamate oxalacetate transaminase, acid phosphatase and alkaline phosphatase. The results suggest the potential application of some of the marine cyanobacteria as pharmaceuticals/modulators of the regulatory system, though a few strains exerted minor toxic effects.
The effects of copper, nickel, and iron on survival, growth, nutrient uptake (NH, NO, and PO), carbon fixation, nitrate reductase, nitrogenase (CH2 reduction assay), glutamine synthetase (transferase), and alkaline phophatase activities of Anabaena doliolum were studied. About 50% survival of the test alga was scored at 8.0 × 10−3, 8.6 × 10−3, and 0.36 mM of Cu, Ni, and Fe, respectively. However 45, 59, and 57% reductions in final yield were scored, respectively, at LD50 concentrations of Cu, Ni, and Fe. On the basis of the LD50 of the test metals, Ni was the most inhibitory for nutrient uptake. However, the LD50 concentrations of Cu, Ni, and Fe showed different levels of inhibition for different processes. Although metal concentrations higher than LD50 were found to be more inhibitory, 0.54 mM iron generated maximum inhibitory effect as compared to Cu and Ni. The present study demonstrates that the test cyanobacterium exhibits metal and dose-specific responses toward different physiological and biochemical processes.
The occurrence and ultrastructure of eubacteria within leaf cavities of symbiotic and cyanobiont-freeAzolla mexicana were examined with transmission electron microscopy. Bacteria were observed in all leaf cavities of bothAzolla cultures, showing increasing numbers concomitant with leaf age. In symbioticAzolla mexicana two ultrastructurally distinct types of bacteria were found; a helical bacterium and a slightly curved, rod-shaped bacterium. Both had typical Gram-negative cell wall ultrastructure. The helical bacteria comprised 60% of the total population in young leaf cavities (1–5) and 74–80% of the population in older cavities. The mode of cell division for the rod-shaped bacterium was binary fission. In cyanobiont-freeAzolla mexicana at least three distinct types of bacteria were observed; two were ultrastructurally similar to, if not identical, with the types present in symbioticAzolla mexicana.
Thirty eight axenic strains belonging to the Chroococcales were screened for the ability to grow photoheterotrophically in the light with glucose in the presence of 10-5 M DCMU, which inhibits photoautotrophic growth. Seven strains could do so, and four of them could also grow chemoheterotrophically, though more slowly, with glucose in the dark. Six are members of the genus Aphanocapsa and one of the genus Chlorogloea. The remaining 31 strains examined appear to be obligate photoautotrophs. A quantitative study of the growth behaviour of one strain, Aphanocapsa 6714, fully confirmed its facultative photoheterotrophy and chemoheterotrophy.
The marine non-heterocystous, filamentous cyanobacteriumPhormidium valderianum BDU 30501, which failed to grow in the absence of combined nitrogen in the medium, grew when supplemented with ampicillin. Growth in terms of both protein as well as chlorophyll was proportional to the concentration of ampicillin up to 2000 g ml–1. With the hydroxylamine assay, the organism was found to produce -lactamase extracellularly with activity reaching a maximum within 6 h of incubation. The maximum production and activity of the enzyme in the culture filtrate was at pH 7 at a concentration of 750 g ml–1 ampicillin and at 25C. The crude enzyme was thermolabile, because temperatures above 0C on storage resulted in the loss of activity within hours. The enzyme could be induced both by ampicillin as well as benzyl penicillin, but ampicillin proved to be a more suitable substrate both in terms of induction as well as activity. This is the first report of an antibiotic serving as a nitrogen source for an organism.
Alkali-extracted biomass of Phormidium valderianum BDU 30501, a marine filamentous, non-heterocystous cyanobacterium adsorbed more than 90% of cadmium ions from solutions containing 0.1–40mM. Cadmium binding accounted up to 18% of biomass weight (w/w). The algal biosorbent was also efficient is sequestering metal ions (Cd2+, Co2+, Cu2+, Ni2+) from a mixture. Biosorbent placed in dialysis tubing could concentrate Cd2+ (50–65%) from 1l solution (10 and 100ppm) at equilibrium. Biosorbent immobilized in polyvinyl foam also removed cadmium and cobalt efficiently, but required longer contact times (24h). Most of the bound metal ions (> 80%) could be desorbed with 0.1M HCl or EDTA, while other reagents were less efficient in the order: H2SO4 > NH4Cl > CaCl2 > Na2SO
4 > KSCN > KCl > NH4OH > NaHCO3. The regenerated biosorbent retained 80% of the initial binding capacity for Cd2+ and 50% binding capacity for Co2+ up to three cycles of reuse. Infrared spectra of the biosorbent preparation suggested carboxyl groups to be the primary sites for metal binding.
Both free and immobilized cells of the algae Chlorella vulgaris and Anacystis nidulans contain aminoacid oxidase (AAO) activity which is increased by illumination with red light. Both immobilized species are photosynthetically active. By co-immobilizing Chlorella with bacterial cells (Providencia sp. PCM 1298) containing high AAO activity an increased production of keto acid (up to tenfold) is observed due to improved oxygen supply.
Bioremediation is a cost-effective alternative to conventional disposal methods and is a new technology which emphasizes
the detoxification and destruction of the pollutants by acclimatized microorganisms. Cyanobacteria are in a more advantageous
position than heterotrophic bacteria because of their trophic independence for nitrogen as well as carbon. Phenol, the toxic
constituent of several industrial effluents, was found to be effectively removed and degraded by the marine cyanobacterium
Phormidium valderianum BDU 30501. The organism was able to tolerate and grow at a phenol concentration of 50 mg L−1 and remove 38 mg L−1 within a retention period of 7 days. The removal and degradation were confirmed by changes in the ultraviolet absorption
spectra in the culture filtrate, colorimetric estimation of residual phenol and measuring the intracellular activity of the
inducible polyphenol oxidase and laccase enzymes. This opens up the possibility of treating a variety of phenol-containing
industrial effluents using this organism.
The inoculation of the soil with the nitrogen fixing blue-green alga,Calothrix anomala had a positive effect onCapsicum annum andLactuca sativa, in terms of yield and percentage nitrogen. A combined application of urea and alga was more effective than their individual applications.
Alkaline phosphatase activity (ALP) (EC: 3.1.3.1) presents a nycthemeral variation in both Microcystis aeruginosa (cyanobacterium) and Synedra capitata (diatom) species. Nevertheless, a comparative study reveals differences between the enzymatic behaviour of these two species. ALP is 33 times higher in cyanobacteria than in diatoms under similar experimental conditions. Microcystis aeruginosa presents therefore a larger capacity for mineralizing organic phosphorus per unit of biomass. Under LD (16:8) conditions, diatoms show a higher enzymatic activity during the day time (around 0.12 μmol pNPP/mn/mg); on the contrary, cyanobacterial enzymatic activity is rather low during the day time and rises at the beginning of night time (around 3.5 μmol pNPP/mn/mg). Finally, the mean of ALP of Synedra capitata is maximal (around 0.12 μmol pNPP/mn/mg) under total darkness (DD) while the mean of enzymatic activity is maximal (around 3.58 μmol pNPP/mn/mg) under permanent light (LL) for the cyanobacteria. These observed differences in the alkaline phosphatase activity between Microcystis aeruginosa and Synedra capitata might, to some extent, explain the observed alternances within the planktonic settlements between algae and cyanobacteria in hypereutrophic lakes such as the Grangent reservoir (Loire).
Vertically stratified microbial communities of phototrophic bacteria in the upper intertidal zones of the North Sea island of Mellum were investigated. Growth and population dynamics of the cyanobacterial mat were followed over three successive years. It was concluded that the initial colonization of the sandy sediments was by the cyanobacterium Oscillatoria. In well-established mats, however, the dominant organism was Microcoleus chthonoplastes. The observed succession of cyanobacteria during mat development is correlated with nitrogen fixation. Nitrogen fixation is necessary in this low-nutrient environment to ensure colonization by mat-constructing cyanobacteria. Under certain conditions, a red layer of purple sulfur bacteria developed underneath the cyanobacterial mat in which Chromatium and Thiocapsa spp. dominated, but Thiopedia and Ectothiorhodospira spp. have also been observed. Measurements of light penetrating the cyanobacterial mat indicated that sufficient light is available for the photosynthetic growth of purple sulfur bacteria. Profiles of oxygen, sulfide and redox potential within the microbial mat were measured using microelectrodes. Maximum oxygen concentrations, measured at a depth of 0.7 mm, reached levels more than twice the normal air saturation. Dissolved sulfide was not detected by the microelectrodes. Determination of acid-distilled sulfide, however, revealed appreciable amounts of bound sulfide in the mat. Redox profiles measured in the mat led to the conclusion that the upper 10 mm of the sedimentary sequence is in a relatively oxidized state.
The biological production of nitrate was studied during the summer of 1976 in the water column of an 18.500 m3 capacity experimental enclosure in Blelham Tarn, English Lake District, to which 11 kg NaNO3 (enriched with 9.63 atom % excess 15N) and 0.789 kg KH2PO4 had been added. Nitrification was detected in the water column during stratification and was maximal within a 2 m deep zone centered on a depth of 8.0 m in the metalimnion and upper hypolimnion, where numbers of autotrophic nitrifying bacteria were highest. Calculated rates of nitrification in this zone based on BOD measurements. N-Serve-sensitive bicarbonate incorporation, regression analysis of the daily changes in nitrate-nitrogen at 8.0 m and integrated changes in nitrate-nitrogen throughout the metalimnion and hypolimnion during late August 1976 were respectively: 55.4, 45.0, 22.4 and 39 μg N 1−1 day−1. The importance of sediment-derived ammonium for nitrifying bacteria and the fate of nitrate produced by nitrification are discussed.
Melanoidin decolorization/degradation has not so far been attempted with cyanobacteria. In this study, we report the ability of a marine filamentous, non-heterocystous form Oscillatoria boryana BDU 92181 to use the recalcitrant biopolymer melanoidin as nitrogen and carbon source leading to decolorization. Indirect evidence through the study of nitrogen assimilating enzymes as well as direct evidence of using 14C radiolabeled synthetic melanoidin confirm this ability. The organism decolorized pure melanoidin pigment (0.1% W/V) by about 75% and crude pigment in the distillery effluent (5% V/V) by about 60% in 30 days. The mechanism of color removal is postulated to be due to the production of hydrogen peroxide, hydroxyl anions and molecular oxygen, released by the cyanobacterium during photosynthesis. This study for the first time, has opened up the possibility of treating distillery effluent in a cost effective way using the marine cyanobacterium.
Bibliogr. na konci kapitol Rozmn
A recently developed tetrazolium-based microculture assay was used to screen extracts of cultured cyanobacteria (blue-green
algae) for inhibition of the cytopathic effects of the human immunodeficiency virus (HIV-1), which is implicated as a causative
agent of AIDS. A number of extracts were found to be remarkably active against the AIDS virus. A new class of HIV-1-inhibitory
compounds, the sulfonic acid-containing glycolipids, was discovered through the use of the microculture assay to guide the
fractionation and purification process. The pure compounds were active against HIV-1 in cultured human lymphoblastoid CEM,
MT-2, LDV-7, and C3-44 cell lines in the tetrazolium assay as well as in p24 viral protein and syncytium formation assays.
[J Natl Cancer Inst 81:1254–1258, 1989]
This chapter focuses on the conjugal transfer of DNA to Cyanobacteria. Conjugation appears to be a general means to introduce DNA from Escherichia coli into cyanobacteria, using the broad host range conjugal apparatus of an IncP plasmid, such as RP4. RP4, originally isolated from Pseudomonas, has been shown to mediate the transfer of DNA into a wide range of gram-negative bacteria, including such distantly related organisms as myxobacteria, thiobacilli, and unicellular and filamentous cyanobacteria. To obtain stable conjugal transfer it is necessary that (1) conjugal contact be made, (2) transferred DNA escape restriction or degradation, and (3) the DNA replicate autonomously or integrate into one of the replicons of the recipient. The first requirement is probably met in the great majority of gram-negative eubacteria, cyanobacteria included. The task for the experimenter is to find conditions that permit the last two requirements to be met as well. Even with transformable unicellular cyanobacteria, conjugation may be the preferred route of DNA transfer in certain cases. DNA taken up by unicellular cyanobacteria appears to be randomly cut early during the transformation process, so that the efficiency of transfer of a segment of nonhomologous DNA decreases exponentially with its length.