Structures of Glucomanno-oligosaccharides from the Hydrolytic Products of Konjac Glucomannan Produced by a β-Mannanase from Streptomyces sp.

Abstract

The hydrolysis of konjac glucomannan by a purified extracellular mannanase from Streptomyces sp. produced four kinds of oligosaccharides containing both glucose and mannose residues. These glucomanno-oligosaccharides were identified as O-β-D-glucopyranosyl-(1→4)-Dmannopyranose (epicellobiose, G₁M₁-I), 0-β-D-glucopyranosyl-(1→4)-O-β-D-mannopyranosyl- (1→4)-D-mannopyranose (G₂M₁-I), O-β-glucopyranosyl-(1 →4)-O-β-D-glucopyranosyl-(1→4)-D-mannopyranose (G₂M₁-I) and O-β-D-glucopyranosyl-(1 →4)-O-β-D-glucopyranosyl-(1→4)-O-β-D-mannopyranosyl-(1→4)-D-mannopyranose (G₂M₂-I). On the basis of the structure of the above oligosaccharides, the mode of action of the mannanase on the glucomannan is discussed.