Immobilization of microbial cells in a mixed matrix of silicone polymer and calcium alginate gel: epoxidation of 1-octene by Nocardia corallina B-276 in organic media.

Immobilization of Nocardia corallina B-276 was examined for production of 1,2-epoxyoctane from 1-octene in the presence of n-hexadecane as the organic solvent. Hydrophobic silicone polymer was the most suitable material for entrapment of the cells. Coentrapment of aqueous reaction medium into the silicone polymer matrix improved the epoxide productivity. It was also effective to immobilize the cells in a mixed matrix composed of silicone polymer and calcium alginate gel involving the reaction medium. In the organic monophase, the amount of epoxide accumulated with the cells immobilized in an almost equivolumetric composite of both materials was 2 and 7 times the amounts in the silicone and alginate single matrices, respectively, and it became larger than with the free cells in the aqueous-organic two-liquid phase after a longer period of batch operation. The use of such an optimized composite matrix enabled us to perform a relatively simple operation of the continuous three-phase bioreactor.