脂肪酶固定化及其稳定性研究

Lipase Immobilization and Its Stability Analysis

目的:研究脂肪酶的固定化工艺及其稳定性。方法: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)固定化黑曲霉属脂肪酶。结果:最优固定化条件是:TMOS 0.5mmol、MTMS 2.5mmol,水与硅烷前驱体摩尔比(R)12,PEG400 120μL,给酶量120mg。酶的固定化效率为93.7%,比活力为游离酶的2.2倍。固定化酶和游离酶在60℃处理2h,其残余酶活分别为91.8%和0;在pH 11的缓冲液中处理2h,其残余酶活分别为95.2%和82%。结论:酶经固定化后其活力、热稳定性和pH稳定性均有提高。

Objective：Lipase immobilization and its stability were studied. Methods：lipase from Aspergillus niger was entrapped in hybrid organic - inorganic sol- gel powder prepared by base- catalyzed polymerization of tetramethoxysilane （TMOS） and methyltreimethoxysila （MTMS）, and the process was optimized. Results： When TMOS 0.5mmol and MTMS 2.5mmol, optimum preparation conditions were water/sliane molar ratio 12, enzyme supply 120 rag, and PEG400 120μL. The percentage of protein immobilization was 93.7% and resulting lipase specific activity was 2.2 times higher than that of a non - immobilized lyophilized lipase. Thermal and pH stability of immobilized lipase were increased appreciably compared with free form. After incubation 2h at 60℃ in Tris - HC1 buffer （pH 7.5, 0.05mol/L）, their residual actiyity were 91.8% and 0 respectively, and after incubation 2h in a buffer of pH 11 at 37℃, their residual activity were 95.2% and 82% reapectively.Conclusion：The activity and stability of hpase after immobilization were highly improved.