SOLVENT EFFECT ON ENZYME-CATALYZED SYNTHESIS OF BETA-D-GLUCOSIDES USING THE REVERSE HYDROLYSIS METHOD - APPLICATION TO THE PREPARATIVE-SCALE SYNTHESIS OF 2-HYDROXYBENZYL AND OCTYL BETA-D-GLUCOPYRANOSIDES

Almond beta-D-glucosidase was used to catalyze alkyl-beta-D-glucoside synthesis by reacting glucose and the alcohol in organic media. The in fluence of five different solvents and the thermodynamic water activit y on the reaction have been studied. The best yields were obtained in 80 or 90% (v/v) tert-butanol, acetone, or acetonitrile where the enzym e is very stable. In this enzymatic synthesis under thermodynamic cont rol, the yield increases as the water activity of the reaction medium decreases. Enzymatic preparative-scale syntheses were performed in a t ert-butanol-water mixture which was found to be the most appropriate m edium. 2-Hydroxybenzyl beta-D-glucopyranoside was obtained in 17% yiel d using a 90:10 (v/v) tert-butanol-water mixture. Octyl-beta-glucopyra noside was obtained in 8% yield using a 60:30:10 (v/v) tert-butanol-oc tanol-water mixture. (C) 1997 by Elsevier Science Inc.