PREPARATIVE, ELECTROENZYMATIC REDUCTION OF KETONES ON AN ALL COMPONENTS-IMMOBILIZED GRAPHITE FELT ELECTRODE

A thin cation-exchange polymer (Nafion)- and poly(acrylic acid) layers -coated graphite felt electrode immobilizing all mediation components of methyl viologen, NAD(+), diaphorase and alcohol dehydrogenase to co nstruct a complete bioelectrochemical reactor was prepared and applied to electroenzymatic reduction of ketones in a phosphate buffer at con stant potential of -0.80 V vs sce. S-Isomers of 2- and 3-methylcyclohe xanone were enantioselectively reduced to the corresponding (1S, 2S)-( +)-2- and (1S, 3S)-(-)-3-methylcyclohexanol, respectively, in high cu rrent efficiency (98.6 and 96.5%), high reduction yield (almost quanti tatively) and high enantiomeric excess (ee) (100 and 93.1%), respectiv ely. The unreacted ketones, (R)-(-)-2- and (R)-(+)-3-methylcyclohexano ne, were recovered in high recovery yield (100 and 96%) and high ee (9 9.6 and 95.8%), respectively. (C) 1997 Elsevier Science Ltd.