A MANNAN PRODUCED BY SACCHAROMYCES ROUXII

The main slime polysaccharide produced by Saccharomyccs rouxii during the fermentation of D-glucose to D-arabitol is a mannan. Acetolysis of the polymer has afforded di- and tri-saccharides in good yield, but no higher oligosaccharides were produced. The disaccharide is shown by methylation and lead tetraacetate oxidation to be 2-O-α-D-mannopyranosyl-D-mannose, establishing the presence of a 1,2-α-linkage in the polysaccharide. On acid hydrolysis the methylated mannan gives mainly 2,3,4,6-tetra-O-methyl-D-mannose, 3,4,6-tri-O-methyl-D-mannose, and 3,4-di-O-methyl-D-mannose; lesser components found are 2,4,6-tri-O-methyl-D-mannose and 3-O-methyl-D-mannose. The methylation and acetolysis data together suggest an average structural unit consisting of a main chain of D-mannopyranose units containing alternate 1,2- and 1,6-linkages, to which single D-mannopyranose units are attached by 1,2-linkages as side chains; alternatively, 1,2-disaccharide units are attached as side chains by 1,2-linkages to a 1,6-linked main chain.