月桂酸生物印迹对脂肪酶酯化活力的影响

生物印迹是改良酶学特性，扩大脂肪酶工业应用领域的新兴技术。本研究结合溶胶-凝胶脂肪酶固定化工艺，以甲基三甲氧基硅烷（MTMS）和四甲氧基硅烷（TMOS）为前驱体，月桂酸为印迹分子，考察了月桂酸生物印迹对脂肪酶PS酯化活力的影响。脂肪酶酯化活力测定及扫描电镜观察表明生物印迹能显著提高脂肪酶的活性及稳定性。印迹体系经正交试验优化获得的最优条件为：水和硅烷摩尔比（R）为12，聚乙二醇（PEG）加入量为120μl，月桂酸加入量为0.15mmol。在最优反应条件下，印迹酶相对于游离酶比活力提高了44.3倍，相对于未印迹固定化酶提高了2.4倍；印迹酶具有较好的热稳定性，在80℃下处理0.5h后，残余酶活分别为58%，而游离酶未检测到活性。

Effect of bioimprinting by lauric acid on esterification activity of lipase

Bioimprinting is a new developed technique to improve the characteristics of enzymes. In this study, bioimprinting by lauric acid was conducted to improve the esterification activity of lipase PS in sol-gel immobilization process with methyltrimethoxysila (MTMS) and tetramethoxysila (TMOS) as the precursors. Results generated by checking the esterification activity and scanning electron microscope showed that bioimprinting can enhance the specific activity and thermal stability of lipase PS. The bioimprinting system was optimized by orthogonal experiment, and the optimal condition for lipase bioimprinting is water/silane molar ration (R) 12, polyethylene glycol (PEG) 120μl, and lauric acid 0.15 mmol. Compared with the free enzyme and the non-imprinted enzymes, the specific activity of imprinted enzymes has been improved 44.3 fold and 2.4 fold, respectively. Imprinted lipase show better thermal stability, and the relative activity is 58% after incubated in 80 ℃ for 0.5 h, while no activity was detected for the free enzyme.