title: Characterization and Optimization of Bioflocculant Exopolysaccharide Production by Cyanobacteria Nostoc sp. BTA97 and Anabaena sp. BTA990 in Culture Conditions.
abstract: Bioflocculant exopolysaccharide (EPS) production by 40 cyanobacterial strains during their photoautotrophic growth was investigated. Highest levels of EPS were produced by Nostoc sp. BTA97 and Anabaena sp. BTA990. EPS production was maximum during stationary growth phase, when nitrogenase activity was very low. Maximum EPS production occurred at pH 8.0 in the absence of any combined nitrogen source. The cyanobacterial EPS consisted of soluble protein and polysaccharide that included substantial amounts of neutral sugars and uronic acid. The EPS isolated from Anabaena sp. BTA990 and Nostoc sp. BTA97 demonstrated high flocculation capacity. There was a positive correlation between uronic acid content and flocculation activity. The flocculant bound a cationic dye, Alcian Blue, indicating it to be polyanionic. The 16S rRNA gene sequences for Nostoc sp. BTA97 and Anabaena sp. BTA990 were deposited at NCBI GenBank, and accession numbers were obtained as KJ830951 and KJ830948, respectively. The results of these experiments indicate that strains Anabaena sp. BTA990 and Nostoc sp. BTA97 are good candidates for the commercial production of EPS and might be utilized in industrial applications as an alternative to synthetic and abiotic flocculants.
authors.affiliation: Freshwater Cyanobacterial and Microalgal Repository, Microbial Resources Division, Institute of Bioresources and Sustainable Development, Takyelpat, Imphal, Manipur, 795001, India, ontiwari1968@gmail.com.
authors.forename: Onkar Nath
authors.initials: ON
authors.lastname: Tiwari
authors.forename: Romi
authors.initials: R
authors.lastname: Khangembam
authors.forename: Minerva
authors.initials: M
authors.lastname: Shamjetshabam
authors.forename: Aribam Subhalaxmi
authors.initials: AS
authors.lastname: Sharma
authors.forename: Gunapati
authors.initials: G
authors.lastname: Oinam
authors.forename: Jerry J
authors.initials: JJ
authors.lastname: Brand
mesh_terms: D017033:Anabaena / Q000737:chemistry / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D046508:Culture Techniques; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D009566:Nitrates / Q000494:pharmacology; D046937:Nostoc / Q000737:chemistry / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D010802:Phylogeny; D011134:Polysaccharides / Q000096:biosynthesis*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014574:Uronic Acids / Q000378:metabolism
chemical_list: D009566:Nitrates; D011134:Polysaccharides; D012336:RNA, Ribosomal, 16S; D014574:Uronic Acids