Recent advances in alcohol dehydrogenase-catalyzed asymmetric production of hydrophobic alcohols

The efficiency of biocatalytic redox reactions catalyzed by alcohol dehydrogenases (ADHs) have been the subject of considerable research recently. Two major challenges have restricted their application in asymmetric synthesis until now. First of all, most of the interesting substrates are either insoluble or sparingly soluble in aqueous media, the natural medium for enzymes. This drawback has been overcome by using non-aqueous media like organic solvents, ionic liquids, and supercritical carbon dioxide in mono- and biphasic reactions, and several ADHs show high activity at high concentrations of such reaction media. The second challenge is the strict substrate specificity for most ADHs. The continuous search for new ADHs, together with random and rational mutagenesis to widen substrate specificity, will help in attracting organic chemists to consider utilizing them in organic synthesis more often. The aim of this perspective is to highlight recent efforts to overcome the above-mentioned limitations.