STRUCTURE OF SIMUSAN, A NEW ACIDIC EXOPOLYSACCHARIDE FROM ARTHROBACTER SP

Simusan, a major exopolysaccharide produced by an ethanol-utilizing Ar throbacter sp. strain CE-17, contains D-glucose, D-mannose, D-galactos e, L-rhamnose, D-glucuronic acid, and pyruvic acid in the ratios simil ar to 3:2:1:1:1:1 as well as O-acyl groups (presumably residues of ace tic and palmitic acid). On the basis of chemical modifications of the polysaccharide, solvolysis with anhydrous hydrogen fluoride resulting in a penta- and an octa-saccharide fragment, Smith degradation, and H- 1 and C-13 NMR analysis, the following structure of the repeating unit was established: [GRAPHICS] It is suggested that at least one of the glucose residues and the galactose residue are O-acetylated.