Small scale production and characterization of alginate from azotobacter chroococcum using different substrates under various stress conditions.

ABSTRACT

Alginates form an important family of biopolymers. These are linear polysaccharides composed of variable amounts of (1–4)-β-D-mannuronic acid and its epimer, α-L-guluronic acid. Currently, commercial alginates are extracted from marine brown algae. Considering the merits of bacterial alginates, optimal fermentation conditions aiming at the maximization of alginate using bacterium Azotobacter chroococcum from different substrates were examined. Whey, molasses, ammonium nitrate, starch, yeast extract, butanol, mannitol, and glucose have been used. The alginate obtained from whey (45.15%), ammonium nitrate (46.02%) and butanol (47.3%) varied. Among the physical stress conditions, the production of alginate was maximum at heat shock 50 0C for 30min (42.96%) followed by 41.29% on UV radiation for 10 min. At pH 7 and 8 the alginate produced was 44.63% and 46.64% respectively. Carbazole reagent was used to recognize alginate; it was lyophilized and quantitated by gas chromatography.