Hemiacetal Dehydrogenation Activity of Alcohel Dehydrogenases in Saccharomyces

ethyl hexanoate (ethyl caproate), and 2-phenylethyl acetate are typical of the carboxylate esters produced by yeasts of the genus Saccharomyces, which are widely used in brewing.i) Two kinds of ester synthetic pathway have been proposed for yeast. One involves the transfer of an acyl group from acyl-CoA to alcohol, catalyzed by alcohol acyltransferase2) or alcohol acetyltransferase (2MTase).3) To date, the AATases involved in the synthesis of 3-methyl-1-butyl acetate and ethyl acetate have been purified from Saccharompces cerevisiae,4,5) and the genes encoding these enzymes have been cloned as A71F16) and A7}72.S) The other pathway comprises the reverse reaction of esterases, in which esters are made directly from alcohols and carboxylates. Certain esters, es-