ENZYME-CATALYZED SYNTHESIS OF OPTICALLY PURE R(+)-PHENYLETHANOL

A dehydrogenase catalyzing the NADPH-dependent reduction of acetophenone to R(+)-phenylethanol was found in Lactobacillus kefir. A continuous conversion of 10 mM acetophenone with a yield of up to 90% was achieved in an enzyme-membrane-reactor with simultaneous NADPH-regeneration using glucose-6-phosphate and glucose-6-phosphate dehydrogenase. Enzyme-catalyzed oxidation of phenylethanol occurred with the R(+)-enantiomer only, whereas S(-) was not converted by the enzyme. The formation of R(+)-phenylethanol with an enantiomeric excess of 100% was confirmed by chiral HPLC. © 1990 Kluwer Academic Publishers.