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 cataly ze the production of alkyl beta-D-xyloside. Two general methods of pro duction are tested and compared using the same enzyme: transglycosylat ion and reverse hydrolysis. Using both methods, primary, secondary, an d tertiary alcohols are studied as accepters. In kinetically controlle d process (transglycosylation), the chosen donor is methyl beta-D-xylo side 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 th e donor concentration is investigated in both processes. The yields of the kinetically controlled reactions are higher compared with those o f the equilibrium-controlled synthesis. The specificity of the beta li nkage is confirmed by proton nuclear magnetic resonance (H-1 NMR) anal ysis. (C) 1994 John Wiley & Sons, Inc.