预处理固定化脂肪酶膜对酯化反应的影响

摘要

考察经多种天然添加剂、活性剂成分及有机相反应前预处理实验室自制固定化酶膜对十二酸十二醇、维生素A/C棕榈酸酯、棕榈酸异辛酯等酯化合成的影响.结果发现:经过明胶、多羟基化合物PVP及含活性剂成分复配乳液PDMS等处理后,酶膜对十二酸十二醇酯化酶活有1.2-1.5倍不同程度提高;相比冻干酶粉完全失活含质量分数98%PEG6000的冻干酶粉催化酯化率在70%以上,结合盐及聚乙二醇高分子化合物对酶保护作用,该方法适于冻干Candida sp.99-125脂肪酶粉的预处理;而在所选常用有机溶剂中酶活性稳定,可用于反应后酶膜的再生.在棕榈酸异辛酯的酯化合成中,复合乳剂PDMS对酶稳定性没有影响,而天然羟基化合物PVP及乳糖明显有利于酶活性的保持、酶重复使用次数的增加.%Immobilized lipase membrane prepared in our lab pre-treated with natural additives and active agent compositions by presoaking in solution, or immersing in organic phase was studied.And the enzymatic character was measured by reaction of lauric acid lauryl ester, vitamin A/C palmitate and ethylhexyl palmitate, as model study of its esterification activity.After natural additives and ingredients emulsion containing surfactant compound treated, an activity increase of 1.2-1.5 times was found in lauric acid lauryl ester reaction.In addition, for freeze-dried lipase powder, the catalytic esterification rate of VA palmitate synthesis was over 70%(freeze-dried enzyme powder mass fraction 98% PEG6000) while the lipase powder without additives having no activity.Considering the protective effect resulting from salt and polyethylene glycol polymers, freeze-dried enzyme powder from Candida sp.99-125 with those additives can be recognized as one kind of pretreatment method.Organic solvents with different hydrophobic constants (almost have no negative effect on lipase activity) can be applied for enzyme regeneration after reaction.Moreover, PVP-360 and lactose are conducive to the stability and using times of the immobilized lipase membrane in esterification of ethylhexyl palmitate.