초록
<P>Alcohol dehydrogenases are able to catalyze the conversion of alcohols to aldehydes or ketones, simultaneously reducing the cofactor NAD<SUP>+</SUP> or NADP<SUP>+</SUP> to NAD(P)H. Because of the high costs of these pyridine cofactors, in situ cofactor regeneration is required for preparative applications in order to reach turnover numbers that are sufficient for economically viable processes. Here we present the development of a process for the enantioselective oxidation of rac-1-phenylethanol to acetophenone, applying an alcohol dehydrogenase coupled with an NAD(P)H oxidase for the enzymatic cofactor regeneration, which is active towards NADH as well as NADPH. The reaction system was investigated in view of various influential parameters with main focus on the external oxygen supply. We could show that a gassed stirred tank reactor is a promising reactor concept to run NAD(P)H oxidase-coupled alcohol dehydrogenase oxidations, including the possibility to scale-up the system.</P><P><B>Graphic Abstract</B><BR><IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/oprdfk/2015/oprdfk.2015.19.issue-11/op500307e/production/images/medium/op-2014-00307e_0006.gif'></P>