EVALUATION OF ALCALIGENES-EUTROPHUS CELLS AS AN NADH REGENERATING CATALYST IN ORGANIC-AQUEOUS 2-PHASE SYSTEM

A soluble NAD-dependent hydrogenase contained in Alcaligenes eutrophus was evaluated as a coenzyme regenerating catalyst in an organic-aqueo us two-phase (predominantly organic) system. The horse-liver alcohol-d ehydrogenase (HLADH) catalyzed reduction of cyclohexanone to cyclohexa nol was used as a model reaction. The impact of different solvents (se lected to span a large variety of principal properties) on the stabili ty and activity of the HLADH, using substrate-driven regeneration, was studied. Solvents suitable for the HLADH were then selected for an ev aluation of the hydrogenase-driven coenzyme regeneration. Hydrophobic solvents such as heptane, toluene, and 1,1,1-trichloroethane were foun d to be suitable for the coupled; reactions catalyzed by HLADH and hyd rogenase. Nonimmobilized cells, permeabilized with cetyl-trimethylammo nium bromide, were the most efficient preparation for the regeneration of NADH. The use of this preparation in heptane (10% water) was optim ized with respect to the yield obtained in the HLADH-catalyzed reducti on of cyclohexanone. Using the optimized conditions, yields of 99% cyc lohexanol were obtained. (C) 1998 John Wiley & Sons, Inc.