超声酶促维生素A棕榈酸酯反应的动力学

考察超声辐照下影响合成维生素A棕榈酸酯反应的因素(溶剂、底物摩尔比、底物浓度、反应时间、酶量和超声功率),并优化了反应条件:在10 mL的正己烷溶剂中,0.164 g维生素A醋酸酯和0.32 g棕榈酸,在酶与维生素A醋酸酯的质量比为1∶4的固定化脂肪酶Novozym 435催化下,超声功率为90 W,反应6 h,酯化率可达82%。并对其动力学进行了研究,由非线性拟合得到动力学参数:最大反应初速率(rmax)为0.522 mmol/(min.g);维生素A醋酸酯的米氏常数为0.404 mmol/L;棕榈酸的米氏常数为0.034 mmol/L。

Lipase catalyzed kinetics of synthesis of retinyl palmitate by ultrasonic irradiation

The synthesis of retinyl palmitate was investigated in organic solvent with immobilized lipase Novozym 435 promoted by ultrasonic irradiation.The influence factors,such as the solvent,the molar ratio and concentrations of substrates,the reaction time,the amount of lipase,and the ultrasonic irradiation power,were studied and optimized.Under the conditions of retinyl acetate of 0.164 g and palmitic acid of 0.32 g,ultrasonic irradiation power of 90 W,solvent hexane of 10 mL,mass ratio of lipase to retinyl acetate of 1∶4,and reaction time of 6 h,82% of retinyl acetate was converted into retinyl plamitate.For the reaction kinetics,the rate constants were obtained by nonlinear fitting with rmax=0.522 mmol/(min·g),KmA=0.404 mmol/L,KmB=0.034 mmol/L.