|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1992 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1991 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1990 : ¥1,100,000 (Direct Cost : ¥1,100,000)
The development of supports for immobilized enzymes and microbial cells in non-aqueous systems is an area of high interest. We applied hydrophobic silicone polymer to immobilization by entrapment of biocatalysts operating in organic media.
1.Horse liver alcohol dehydrogenase,which was once solubilized in a small amount of water,or impregnated in water-containing porous particles,was immobilized in a silicone polymer sheet. This configuration also enabled to perform a simple packed-bed operation for the enzymatic oxidation of alcohol and reduction of aldehyde with a coupled-substrate coenzyme recycling in organic media.
2.Immobilization of Nocardia corallina was examined for epoxidation of liquid alkenes such as 1-tetradecene,1-octene and styrene to produce corresponding epoxides in the presence of n-hexadecane as the organic solvent. The silicone polymer in which droplets of the cell suspension were finely dispersed,was the most suitable material retaining high epoxide productivity. In o
rder to change hydrophobicity-hydrophilicity balance of the support over a wide range,it was effective to immobilize the cells in a mixed matrix composed of silicone polymer and calcium alginate gel. In the support containing excess silicone over 60%,fine particles of the alginate were dispersed in the continuous silicone phase,and in the case of alginate over 40% the phase configuration was inversed. The optimum composition of the mixed matrix 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 closely related to the degree of substrate inhibition. Such an optimized composite-immobilized cells offered the epoxide productivity superior to the free cells in the two-liquid phase after a longer period of batch operation,and enabled to perform a relatively simple operation of a continuous three-phase bioreactor system. Less