The oxidations of alcohols via hydrogen transfer represents an environmental benign 'green' redox protocol. In this context biocatalytic hydrogen transfer employing the alcohol dehydrogenase ADH-'A' from Rhodococcus ruber DSM 44541 results in oxidation of sec-alcohols in aqueous medium at room temperature. High concentrations of the hydrogen acceptor (acetone, up to 50% v/v) are tolerated by the enzyme. Examples for the enantio-, and regioselective oxidation of sec-alcohols employing ADH-'A' in the wild type strain as well as over-expressed ADH-'A' in E. coli are given. (c) 2006 Elsevier B.V. All rights reserved.