Structure of the extracellular polysaccharide produced by the bacterium Alcaligenes (ATCC 31555) species

Abstract

The extracellular anionic polysaccharide produced by the bacterium Alcaligenes (ATCC 31555) contains l-mannose, l-rhamnose, d-glucose, and d-glucuronic acid in the molar ratios 1.0:4.5:3.1:2.3. Analysis of the methylated and methylated, carboxyl-reduced polysaccharide indicated terminal non-reducing rhamnose and mannose, (1→4)-linked rhamnose, (1→3)- and (1→3,1→4)-linked glucose, and (1→4)-linked glucuronic acid to be present in the ratios 1.0:0.8:2.1:2.2:2.0:2.2. Partial acid hydrolysis and base-catalysed β-elimination gave a series of oligosaccharides that were isolated as their alkylated alditol derivatives by reverse-phase h.p.l.c. and characterised by f.a.b.-m.s., e.i.-m.s., and 1H-n.m.r. spectroscopy. The repeating unit 1, excluding O-acyl groups, is proposed. ▪