界面活化的溶胶凝胶包埋Candida rugosa脂肪酶催化合成维生素E琥珀酸酯

采用界面活化的溶胶凝胶包埋Candida rugosa脂肪酶(CRL)催化合成了维生素E琥珀酸酯.考察了影响溶胶凝胶包埋固定化CRL的因素,获得的最佳固定化条件为:丙基三甲氧基硅烷/正硅酸四乙酯摩尔比为1/1,水与硅烷前体摩尔比为15,酶的添加量为0.5mg/ml,PEG400的添加量为12μl/ml溶胶. 溶胶凝胶包埋的CRL在50℃,18h后其活性仍然保持了70.58%,是游离酶的2.6倍,且稳定性得到了明显的改善.基于CRL的界面特性,采用五种表面活性剂对其进行界面活化.结果表明,采用橄榄油活化的溶胶凝胶包埋的CRL合成维生素E琥珀酸酯的酯化活力最高,相比原酶和未界面活化的溶胶凝胶包埋酶分别提高了6.7和1.43倍.

Synthesis of vitamin E succinate by interfacial activated Candida rugosa lipase encapsulated in sol-gel materials

Vitamin E succinate was synthesized by interfacial activated Candida rugosa lipase (CRL) encapsulated in sol-gel materials. The effects of various immobilization parameters were investigated. The optimum conditions were found to consist of n-propyltrimethoxysilane/tetraethoxysilane molar ratio=1/1, water/silane molar ratio (R value)=20, lipase loading=0.5 mg/ml sol, and PEG400 loading=12 μl/ml sol. Compared with free enzymes, sol-gel encapsulated enzymes kept its activity of 70.58% and achieved 2.6-fold increased stability after 18 h incubation in phosphate buffer (0.025 mol/L, pH=7.0) at 50℃. Based on the interfacial characteristics of CRL, five kinds of surfactants were used for activation. The results demonstrate that olive oil was the most effective in activating CRL. The esterification activity of vitamin E succinate synthesis by interfacial activated CRL encapsulated in sol-gel materials reached up to 6.7-fold and 1.43-fold that of free enzyme and non-interfacial activated enzyme, respectively.