Kai Zhu, Jianqiang Wang, Yan-hua Wang, Hui Liu, Ping-fang Han, Ping Wei
College of Life Science and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing, 210009, China.
J Nanosci Nanotechnol. 2011 Sep;11(9):7593-602. doi: 10.1166/jnn.2011.4731.
Candida sp.99-125 lipase was suitable for transesterification of fats and oils to produce fatty acid methyl ester. The adsorption of Candida sp.99-125 lipase onto the fiber-like SBA-15 mesoporous material has been studied. The unaltered structural order of the fiber-like SBA-15 before and after the adsorption has been confirmed by FT-IR, SEM and N2 adsorption. The amount of adsorbed Candida sp.99-125 lipase depends both on the solution pH and reaction time. Good adsorption capacity of Candida sp.99-125 lipase on fiber-like SBA-15 may be due to solution pH from 5.0 to 9.0 especially at 7.0 (93.99 mg enzyme per gram silica is obtained and the activity recovery is 281.05%). A high lipase loading (135.9 mg enzyme per gram silica) was obtained, but it did not produce a proportionate level of catalytic activity. The immobilized Candida sp.99-125 lipase showed increased adaptability in the hydrolysis of p-nitrophenyl acetate compared to free Candida sp.99-125 lipase at pH 5.0-9.0. Meanwhile, the immobilized Candida sp.99-125 lipase showed higher thermal stability than that of free Candida sp.99-125 lipase. And the synthesis of retinyl palmitate in organic solvent with the immobilized Candida sp.99-125 lipase was investigated. The influence factors, such as: the solvent used, the molar ratio and concentrations of substrates, the reaction time and the amount of lipase were studied and optimized. In the conditions of transesterificating 0.164 g retinyl acetate and 0.32 g palmitic acid, 10 mL of solvent hexane, 1:4 of mass ratio of lipase to retinyl acetate, and 6 hours of reaction time, 74.6% of retinyl acetate was converted into retinyl plamitate.
假丝酵母99 - 125脂肪酶适用于油脂的酯交换反应以生产脂肪酸甲酯。已对假丝酵母99 - 125脂肪酶在纤维状SBA - 15介孔材料上的吸附进行了研究。通过傅里叶变换红外光谱（FT - IR）、扫描电子显微镜（SEM）和氮气吸附证实了吸附前后纤维状SBA - 15的结构有序性未改变。假丝酵母99 - 125脂肪酶的吸附量取决于溶液的pH值和反应时间。假丝酵母99 - 125脂肪酶对纤维状SBA - 15具有良好的吸附能力，这可能归因于pH值在5.0至9.0之间，尤其是在pH 7.0时（每克二氧化硅可获得93.99毫克酶，活性回收率为281.05%）。获得了较高的脂肪酶负载量（每克二氧化硅135.9毫克酶），但并未产生相应比例的催化活性。与游离的假丝酵母99 - 125脂肪酶相比，固定化的假丝酵母99 - 125脂肪酶在pH 5.0 - 9.0条件下对乙酸对硝基苯酯的水解表现出更高的适应性。同时，固定化的假丝酵母99 - 125脂肪酶比游离的假丝酵母99 - 125脂肪酶具有更高的热稳定性。并且对固定化的假丝酵母99 - 125脂肪酶在有机溶剂中合成棕榈酸视黄酯进行了研究。研究并优化了诸如所用溶剂、底物的摩尔比和浓度、反应时间以及脂肪酶用量等影响因素。在酯交换0.164克乙酸视黄酯和0.32克棕榈酸、10毫升溶剂己烷、脂肪酶与乙酸视黄酯质量比为1:4以及反应时间为6小时的条件下，74.6%的乙酸视黄酯转化为棕榈酸视黄酯。
