Characterization of the Immobilized β-Galactosidase C from Bacillus circulans and the Production of β(1→3)-linked Disaccharides.

A recombinant β-galactosidase, which was obtained from the β-galactosidase C gene of Bacillus circulans and cleaves the non-reducing end galactosyl residue of β(1→3)-linkages selectively, was immobilized using CNBr-Sepharose. Although the effect of pH was not changed by the immobilization, the thermostability and stability in the presence of DMF were increased. Optimization of the transglycosylation using para-nitrophenyl β-D-galactopyranoside as a donor and benzyl-α-D-N-acetylgalactosaminide as an acceptor afforded a β(1→3)-linked disaccharide derivative with 62% molar yield in a gram scale synthesis. Using the methyl-analogue as an acceptor, 53% of the acceptor was converted to the respective β(1→3)-disaccharide.