Isolation of an exopolysaccharide-producing bacterium, Sphingomonas sp. CS101, which forms an unusual type of sphingan

Abstract

An exopolysaccharide-producing Gram negative bacterium was isolated and determined to be a Sphingomonas sp. (CS101). A sugar composition analysis of an exopolysaccharide indicated that the Sphingomonas sp. CS101 secreted an exopolysaccharide composed of glucose, mannose, fucose, and rhamnose in the ratio of 2.1:1.1:1.0:0.1, suggesting that this exoplysaccharide is an unusual type of sphingan family. The mean molecular weight of the exopolysaccharide was determined to be 4.2 × 105 Da by size exclusion chromatography coupled with multi-angle laser-light scattering (SEC/ MALLS) analysis. An exopolysaccharide was produced up to 17 g/l (pH 7; 30°C) with the optimal medium condition over 4 days of cultivation.