2-O-methyl-D-mannose in an extracellular polysaccharide from Hyphomicrobium sp..

Abstract

An extracellular acidic polysaccharide, hyphomicran, produced by Hyphomicrobium sp. JTS-811 from methanol contained a new monomethyl sugar in nature, which was identified as 1-O-methyl-D-mannose by spectrometry and synthesis. Hyphomicran was found to consist of D-glucose, D-mannose, 2-O-methyl-D-mannose and pyruvic acid residues in the relative proportions of 2:1:1:1. By methylation analysis, pyruvic acid was proved to be linked as a ketal to O-4 and O-6 of a terminal 2-O-methyl-D-mannopyranosyl residue.