The structure of the carbohydrate moiety of an acidic polysaccharide produced by Aureobasidium sp. K-1.

An acidic polysaccharide was isolated from the culture broth of Aureobasidium sp.K-l.The polysaccharide ([a]^0 -10°) was composed of D-glucose and sulfoacetic acid.The glucan moiety was hydrolyzed by ex6>-/M,3-glucanase to give glucose and gentiobiose (molar ratio, ca. 1 : 3).The methylated glucan yielded on acid hydrolysis 2,3,4,6-tetra-O-methyl-, 2,4,6-tri-Omethyl-and 2,4di-O-methyl-D-glucose (molar ratio, 2.6 : 1.0 : 2.7) together with small amounts of 2,3,6-tri-Omethyl-D-glucose.Smith degradation of the glucan moiety yielded glucose, glycerol and erythritol (molar ratio, 4: 3.1 :trace).From these results, it was suggested that the glucan consists of a backbone of /M,3-linked glucose residues containing single branches of glucose residues joined by /M,6-linkages, roughly three out of every four glucose residues in the backbone.