Characterization of eps produced from stem and root nodulating rhizobium mayense

Exopolysaccharides (EPS) are high molecular weight polymers with long chain composed of sugar residues and secreted by microorganisms into the surrounding environment. Bacterial EPS has a complex mixture of macro molecular poly electrolytes including carbohydrates, proteins and sometimes nucleic acids, each comprising variable molecular mass and structural properties. Stem and root nodulating isolate of Aeschynomene indica plant was identified by 16S rRNA sequencing as Rhizobium mayense. Efficiency of Rhizobium mayense was studied using Yeast Extract Agar as a basal medium with different carbon sources and the incubation was done at 30⁰ for 48 hours. The dry weight of EPS was found to be 1.4119 gm /100 ml in Yeast Extract Mannitol Agar. Surface topology of EPS was found smooth by Scanning Electron Microscopy. Alcohol precipitated EPS was further purified using Sephadex G200 and Sephadex G100 gels. The physicochemical characterization of purified EPS was studied and the structural characterization was confirmed by FT-IR, 2D NMR, HPLC and GC-MS analysis.