title: Evaluation of Alcaligenes eutrophus cells as an NADH regenerating catalyst in organic-aqueous two-phase system.
abstract: A soluble NAD-dependent hydrogenase contained in Alcaligenes eutrophus was evaluated as a coenzyme regenerating catalyst in an organic-aqueous two-phase (predominantly organic) system. The horse-liver alcohol-dehydrogenase (HLADH) catalyzed reduction of cyclohexanone to cyclohexanol was used as a model reaction. The impact of different solvents (selected to span a large variety of principal properties) on the stability and activity of the HLADH, using substrate-driven regeneration, was studied. Solvents suitable for the HLADH were then selected for an evaluation of the hydrogenase-driven coenzyme regeneration. Hydrophobic solvents such as heptane, toluene, and 1,1,1-trichloroethane were found to be suitable for the coupled reactions catalyzed by HLADH and hydrogenase. Nonimmobilized cells, permeabilized with cetyl-trimethyl-ammonium bromide, were the most efficient preparation for the regeneration of NADH. The use of this preparation in heptane (10% water) was optimized with respect to the yield obtained in the HLADH-catalyzed reduction of cyclohexanone. Using the optimized conditions, yields of 99% cyclohexanol were obtained.
authors: Department of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, Sweden. Mats.Andersson@biotek.lu.se
authors: M
authors: M
authors: Andersson
authors: H
authors: H
authors: Holmberg
authors: P
authors: P
authors: Adlercreutz
mesh_terms: D000421:Alcaligenes / Q000378:metabolism*; D000426:Alcohol Dehydrogenase / Q000378:metabolism; D000818:Animals; D001709:Biotechnology; D002384:Catalysis; D002463:Cell Membrane Permeability; D003067:Coenzymes / Q000378:metabolism; D003511:Cyclohexanols / Q000378:metabolism; D003512:Cyclohexanones / Q000378:metabolism; D006736:Horses; D066298:In Vitro Techniques; D008099:Liver / Q000201:enzymology; D008954:Models, Biological; D009243:NAD / Q000096:biosynthesis*; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D012997:Solvents; D014867:Water
chemical_list: D003067:Coenzymes; D003511:Cyclohexanols; D003512:Cyclohexanones; D012997:Solvents; D014867:Water; D009243:NAD; C036468:cyclohexanone; D000426:Alcohol Dehydrogenase; D009247:NADH, NADPH Oxidoreductases