Optical resolution of racemic citronellol via a double coupling system in an interface bioreactor

A double coupling system consisting of acetyl coenzyme A [acetyl-CoA] forma tion via the metabolism of glucose and the subsequent acetylation of a prim ary alcohol by acetyl-CoA with the aid of alcohol acetyltransferase [AATFas e], was applied for the optical resolution of racemic citronellol. Pichia k luyveri IFO 1165 was superior for the optical resolution of racemic citrone llol and provided (S)-citronellyl acetate and (R)-citronellol with high ena ntioselectivity and yield. The strain also exhibited excellent resistance t o high concentrations of citronellol, i.e., it could maintain metabolism an d enantioselective acetylation even in the presence of 30% citronellol. The coupling system using P. kluyveri IFO 1165 was applied to two new types of interface bioreactors, tentatively referred to as bead-packed and multisto ry interface bioreactors. Using the latter bioreactor, (S)-citronellyl acet ate and (R) citronellol were produced in large amounts at high enantioselec tivity and yield.