丙烯酸树脂调节假单胞菌脂肪酶(PCL)的催化作用

Polyacrylic resin mediated catalysis of Pseudomonas cepacia lipase

为提高非水相酶促合成酯类食用香精的效率,以亲水性丙烯酸树脂为调节剂,通过物理吸附,将假单胞菌脂肪酶Pseudomonas cepacia lipase固定在玻璃和塑料瓶壁上,并用于催化正己醇与乙酸乙烯酯发生转酯反应,合成乙酸正己酯。结果发现,在玻璃瓶壁上的固定化酶活性不理想,但在聚对苯二甲酸乙二醇酯塑料瓶壁上的固定化酶活性显著升高。催化2 h,从底物转化率看,相对于酶粉,塑料瓶壁上固定化酶的活性提高14倍。红外光谱分析表明,固定化酶的α-螺旋含量34.5%,高于酶粉中的含量29.6%,使用24 h,降低到30.9%。说明树脂调节的固定化作用很好地优化了酶的构象,但酶的稳定性有待进一步提高。

In order to enhance enzyme-catalyzed synthesis of esters used as edible essence in nonaqueous phase, Pseudomonas cepacia lipase was immobilized on the inner wall of glass and plastics bottles by physical adsorption with polyacrylic resin as regulator, and used to catalyze hexanol reacting with vinyl acetate for synthesis of hexyl acetate. The result is that the lipase was not fine in catalysis when it was immobilized. But its activity was superior when immobilized on plastic wall of polyethylene glycol terephthalate. After catalyzing for 2 h, the lipase on the plastic wall had a 14-fold improvement in catalytic activity than native lipase in view of substrate conversion. Infrared spectra showed that the activity-high immobilized lipase contented 34.5% of a-helix, being higher than 29.6% in native lipase. However, the percent content of a-helix decreased to 30.9% after this immobilized lipase was used as catalyst for 24 h. It implied that resin-mediated immobilization had optimized lipase conformation but the stabilization of conformation needed to be improved in the future.