© Indian Institute of Science Microbial exopolysaccharides: Effect on corrosion and partial chemical characterization

Test panels of mild steel were deployed in the surface waters of the Dona Paula Bay over a period of 28 days. Biofilm material on mild steel panels was analyzed for biofilm biomass las organic carbon), exopolysaccharide (EPS) produc-tion and corrosion rates Concentrations of biofilm carbon and EPS increased whereas corrosion rate of mild steel decreased over the period of immersion. Corrosion of mild steel showed significant inverse relationships with biofilm carbon and EPS. This implies that biofilm organic matter inhibits the corrosion of mild steel A few bacterial cultures isolated from the microfouling material were screened for EPS production One of the cultures identified as Vibro sp. produced the highest amount of exopolysaccharides Production, isolation and characterization of the exopolysaccha-rides produced by the bacterium were evaluated. Exopolysaccharide was produced in all the phases of grow'th and with all the substrates tested. Production of the exopolysaccharide was influenced by source and concentration of carbon and nitrogen as well as concentration of phosphate in the growth medium. Exopolysaccharide is a heteropolysaccha-ride-containing glucose as the most abundant monosaccharide and mannose. xylose, galactose and fucose as minor sugars. The presence of uronic acid and pyruvate indicates the acidic nature of the polysaccharide