固定化脂肪酶性质及其应用研究

Studies on stability of immobilized lipase and its application

利用以四甲氧基硅烷（TMOS）和甲基三甲氧基硅烷（MTMS）为前驱体的溶胶．凝胶法（sol-gel）固定洋葱假单胞菌属脂肪酶，考查了固定化酶和游离酶的酶学性质及催化不同油脂酯交换合成生物柴油的情况。结果表明，80℃以下固定化酶能保持80％以上的酶活，而游离酶在50℃以后活力急剧下降，到80℃残余酶活约为10％；固定化酶在体积分数50％的甲醇中处理48h能保持85％的酶活，在体积分数90％的乙醇中处理48h能保持31％的酶活，而游离酶残余酶活只有69％和0；在酯交换反应中固定化酶的催化效率比游离酶高10％-20％，且固定化酶重复使用11次后仍能保持60％的酶活。结果显示，酶经过固定化后稳定性和催化活性显著提高。

Lipase from Pseudomonas cepacia was entrapped in hybrid organic-inorganic sol-gel powder prepared by base-catalyzed polymerization of tetramethoxysilane （TMOS） and methyhreimethoxysila （MTMS）. Its characteristics and application in the transesterification of different oils were studied. The results showed that immobilized lipase remained over 80% of its activity when the temperature was below 80~C while the residual activity of free ones was decreased rapidly when the temperature was over 50℃, and only 10% was remained when the temperature was 80℃. After incubation 48 h in 50% methanol solvent,the residual activity of immobilized lipase and free one were 85% and 69% respectively and after incubation 48 h in 90% ethanol solvent, the residual activity of immobilized lipase and free one were 31% and 0 respectively. Moreover, in the transesterification reactions, the catalyzing efficiency of immo- bilized lipase was 10% - 20% higher than that of the free one. After continuously used for 11 times, 60% residual activity of immobilized lipase was remained. These results indicated the stability and activity of lipase when immobilized were highly improved.