THE SYNTHESIS OF NEW XYLOSYLOLIGOSACCHARIDES BY TRANSXYLOSYLATION WITH ASPERGILLUS-NIGER BETA-XYLOSIDASE

The synthesis of xylosyloligosaccharides from beta-(1 --> 4)-xylobiose in the presence of D-mannose by transxylosylation with beta-xylosidase from Aspergillus niger IFO 6662 was studied. At first, the transxylosylation products were separated by charcoal column chromatography in 5% ethanol elution into three peaks, P-1, P-2, and P-3. They were further separated on thin layer chromatography, and their three products, saccharides O-4, O-5, and O-N were purified by preparative paper chromatography. Saccharides O-4 and O-5 were identified as O-beta-D-xylopyranosyl-(1 --> 4)-D-mannopyranose and O-beta-D-xylopyranosyl-(1 --> 6)-D-mannopyranose, respectively, by measurement of the degree of polymerization, specific rotation, acid hydrolysis, and methylation analysis. By H-1-NMR spectroscopy in addition to these analyses, saccharide O-N was identified as O-beta-D-xylopyranosyl-(1 --> 1')-beta-D-xylopyranose, a new nonreducing xylobiose.