The present invention relates to compositions and methods utilizing thermostable and novel alcohol dehydrogenase enzymes for biosynthesizing chiral specific molecules for use as precursor molecules in synthesizing pharmaceutical compounds. Particularly, in preferred embodiments, the invention relates to directed engineering of an enzymatic catalytic site of an alcohol dehydrogenase enzyme gene for enhancing enantioselectivity for (S)-enantiomer substrate catalytic activity for providing aryl (S)-enantiomer products in stereomeric excess.