ENZYMATIC-SYNTHESIS OF ALKYL BETA-D-XYLOSIDES BY TRANSXYLOSYLATION AND REVERSE HYDROLYSIS

The Trichoderma reesei beta-xylosidase (EC 3.2.1.37) is used to catalyze the production of alkyl beta-D-xyloside. Two general methods of production are tested and compared using the same enzyme: transglycosylation and reverse hydrolysis. Using both methods, primary, secondary, and tertiary alcohols are studied as accepters. In kinetically controlled process (transglycosylation), the chosen donor is methyl beta-D-xyloside and primary, secondary, and tertiary alkyl alcohols are accepted. In the equilibrium-controlled synthesis, the donor is xylose whereas accepters are only primary and secondary alcohols. The influence of the donor concentration is investigated in both processes. The yields of the kinetically controlled reactions are higher compared with those of the equilibrium-controlled synthesis. The specificity of the beta linkage is confirmed by proton nuclear magnetic resonance (H-1 NMR) analysis. (C) 1994 John Wiley & Sons, Inc.