Silicone-immobilized biocatalysts effective for bioconversions in nonaqueous media.
A hydrophobic silicone polymer could be effectively applied to immobilization of two kinds of biocatalysts operating in organic media. Horse liver alcohol dehydrogenase, which was solubilized in a small amount of water, or deposited on water-filled hydrophilic particles, was immobilized in this material. This configuration of the preparation involving finely dispersed aqueous phase permitted a simple packed-bed operation for the enzymatic oxidation of alcohol and reduction of aldehyde with a coupled-substrate NAD(H) recycling in n-hexane. Another example was the immobilization of Nocardia corallina which catalysed epoxidation of liquid alkenes such as 1-tetradecene, 1-octene, and styrene in the presence of n-hexadecane. In order to adjust the hydrophobicity-hydrophilicity balance of the support, it was effective to immobilize the cells in a mixed matrix composed of silicone polymer and Ca-alginate gel. The optimum composition of the mixed matrix, which yielded the highest productivity of epoxide, was 80-90% silicone + 20-10% alginate for the production of 1,2-epoxytetradecane, 40-50% silicone + 60-50% alginate for 1,2-epoxyoctane, and almost 0% silicone + 100% alginate for styrene oxide. This significant change of the optimum composition was primarily associated with the degree of substrate inhibition.
Department of Chemical Engineering, Kyushu University, Japan.
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Kawakami
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T
Abe
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T
Yoshida
D000426:Alcohol Dehydrogenase / Q000378:metabolism*; D000818:Animals; D001711:Biotransformation; D002384:Catalysis; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006736:Horses; D007700:Kinetics; D008099:Liver; D012828:Silicones
D004800:Enzymes, Immobilized; D012828:Silicones; D000426:Alcohol Dehydrogenase