Two-phase system membrane reactor with cofactor recycling.
For the purpose of constructing a two-phase system reactor the enzymatic process of l-menthol production with cofactor recycling was studied as a model. The half-life of the menthone reductase immobilized onto activated carbon was 4 times as high as that of the free enzyme. The enzyme was capable of regenerating NADH when methyl isobutyl carbinol was used as a second substrate. Continuous production of l-menthol was achieved by using a reactor equipped with a hydrophobic microfiltration membrane. It was found that both NAD(H) and the enzyme could be retained in the reactor and the products, l-methanol and methyl isobutyl ketone, passed through the membrane. The production of l-methanol was maintained for 270 h at a rate of 46.1 g l-1 d-1, and had decreased by one-half at 607 h. The recycling number of NAD(H) was 2500 (max. 3020) during the operation. The number of theoretical plates was calculated to be 40 for the separation of l-menthol from other reactants.
Kise
S
S
Department of Bioscience Research Center, Mitsui Petrochemical Industries, Ltd., Yamaguchi, Japan.
Hayashida
M
M
D003067:Coenzymes; D004795:Enzyme Stability; D008567:Membranes, Artificial; D008851:Micropore Filters; D009243:NAD / Q000378:metabolism
D003067:Coenzymes; D008567:Membranes, Artificial; D009243:NAD