OLIGOSACCHARIDE AND ALKYL BETA-GALACTOPYRANOSIDE SYNTHESIS FROM LACTOSE WITH CALDOCELLUM-SACCHAROLYTICUM BETA-GLYCOSIDASE

The synthetic utility of the thermostable beta-glycosidase from Caldoc ellum saccharolyticum was investigated. The ability of the enzyme to c atalyze oligosaccharide and beta-galactopyranoside synthesis from lact ose was compared with that of the readily commercially available, mode rately thermostable beta-galactosidase (beta-D-galactoside galactohydr olase, EC 3.2.1,23) from Aspergillus oryzae. Generally the C. saccharo lyticum enzyme showed significantly greater resistance to inactivation by heat and organic solvent and better yields of product. Although th e A. oryzae enzyme gave better oligosaccharide yields at lower lactose concentrations, at higher concentrations (above 50% w/w) the C. sacch arolyticum enzyme was significantly better, yielding a sugar mixture c ontaining 42% by weight of tri- plus tetra-saccharides, from a 70% w/w lactose solution, compared with 31% by weight of oligosaccharides wit h the A. oryzae enzyme. In ethyl galactoside synthesis from ethanol an d lactose, neither enzyme appeared to hydrolyze the product to any gre at extent. Under all conditions rested, the product yield did not peak , even at long reaction times, when most of the lacro;ze had been cons umed. The C. saccharolyticum enzyme, however, gave slightly higher pro duct yields and could be used at higher ethanol concentrations without serious loss of activity.