有机相中固定化脂肪酶催化合成植物甾醇酯

Synthesis of phytosterol esters catalyzed by immobilized lipase in organic media

酶法合成植物甾醇酯具有反应条件温和、产物纯度和产量高等优点,但非水相酶催化的活性和稳定性普遍较低.本文以大孔树脂固定化脂肪酶为催化剂,并在催化过程中添加乳糖的类似物,构建了有机相高效合成植物甾醇酯的工艺过程.以酯化率为考察指标,对脂肪酶和反应溶剂进行筛选,对酯化条件进行优化,同时考察了糖的种类及添加量对酶催化性能的影响.结果表明,大孔树脂NKA吸附固定化的褶皱假丝酵母(Candida rugosa)脂肪酶(NKA-CRL)为最适宜的催化剂,以正己烷为反应介质,在酸醇摩尔比为2和添加酶蛋白质量7.5%的海藻糖的条件下,40°C反应10 h,酯化率达到96.6%.连续6次催化后,植物甾醇的酯化率仍维持在85.0%以上.

Lipase-catalyzed synthesis of phytosterol esters has the advantages of mild reaction conditions and high product purity and yield. However, the activity and stability of enzymes in a non-aqueous phase are generally lower than in an aqueous phase. In this study, a highly efficient synthesis of phytosterol esters was established by using immobilized lipase on a macroporous resin as the cata-lyst and adding the analogues of lactose during the enzyme catalyzed reaction. In order to facilitate the application of the esterification of phytosterol, the lipases and solvents were screened and the conditions were optimized. In addition, the quantity and type of carbohydrates were investigated, which indicated that immobilized Candida rugosa lipase on NKA (NKA-CRL) was the best catalyst. With a molar ratio of lauric acid to phytosterol of 2, 7.5%enzyme protein added and the reaction carried out at 40 °C in n-hexane, the esterification rate reached 96.6%after 10 h, and the esterifica-tion rate was still above 85.0%after six recycles.