Structural characterization and applications of a novel polysaccharide produced by Azospirillum lipoferum MTCC 2306

Azospirillum lipoferum MTCC 2306, a free-living nitrogen fixing bacteria, has a doubling time of 1.7h in MPSS media. At the end of 28h at a pH of 7 and temperature of 30 degrees C it produces 1.8 +/- 0.013g/L biomass and 2.1 +/- 0.018g/L of cyclic beta glucan (CG) in MPSS medium with a yield coefficient (Y-P/S) of 2.1. This novel polysaccharide is a water-soluble cyclic biopolymer and is generally produced by Rhizobiaceae and predominantly made up of glucose. The CG has a degree of polymerisation varying between 10 and 13 and has both - and -glycosidic linkages. It is not substituted with any functional groups such as acetates or succinates. Its ability to bind to aniline blue suggests that it can be a potential candidate for being used ascarrier in medical imaging as well as in reducing toxicity of textile effluents. It is able to encapsulate rifampicin, a hydrophobic drug and increase its aqueous solubility by 71%. So, CG appears to have promising applications in the field of drug, food, cosmetic and nutraceutical industries.