The Preparation And Characterization Of A Novel Sphingan Wl From Marine Sphingomonas Sp Wg

Sphingans, a group of structurally closely related bacterial exopolysaccharides produced by members of the genus Sphingomonas, can be applied in a variety of industries such as food, cement, and personal care applications due to their high viscosity. A high sphingan-producing-bacterium, Sphingomonas sp. WG can secret large quantity of sphingan designated as WL. To enhance the production of WL, a three-stage control strategy was applied and the highest WL production can reach 33.3 g/L. The rheological analysis showed that the aqueous solution of WL had high viscosity, typical shearing-thinning behavior and great stability to high temperature, a wide range of pH (1 to 14), and high salinity. WL was composed principally of carbohydrate with 6.52% O-acyl groups. The carbohydrate portion of WL contained about 13% glucuronic acid and some neutral sugars including mannose, glucose and rhamnose in the molar ratio of 1: 2.28: 2.12. Partial acid hydrolysis of WL produced a new oligosaccharide WL-1. Structural resolution revealed that WL-1 consisted of alpha-L-Rha-(1 -> 4)-beta-L-Rha-(1 -> 4)-beta-D-Glc- (1 -> 3)-alpha-D-Glc with beta-D-Man substituent at the third glucose residue and carboxyl and O-acyl groups. These findings will broaden the applications of this novel sphingan in food, ink, oil and other industries.