Hydrolysis of Lactose by Microbial β-Galactosidases. Formation of Oligosaccharides with Special Reference to 2-0-β-D-galactopyranosyl-D-glucose

Abstract

The transgalactosylation of lactose by Saccharomyces fragilis β-galactosidase and Aspergillus niger β-galactosidase was examined. With S. fragilis β-galactosidase, twelve oligosaccharides including five disaccharides were detected on paper chromatograms. With A. niger β-galactosidase, ten oligosaccharides were formed. The disaccharides formed by A. niger β-galactosidase were similar to those by S. fragilis β-galactosidase. These disaccharides were isolated by preparative paper chromatography and their structures were explored by gas-liquid chromatography of their methylated methanolyzates. Comparisons of mobility and color of the spots on paper electrophoretograms were also carried out. The disaccharides proved to be 2-0-β-D-galactopyranosyl-D-glucose, 3-0-β-D-galactopyranosyl-D-glucose, 6-0-β-D-galactopyranosyl-D-glucose, 3-0-β-D-galactopyranosyl-D-galactose, and 6-0-β-D-galactopyranosyl-D-galactose. © 1978, American Dairy Science Association. All rights reserved.