Biotechnology Center, National Chung Hsing University, 250 Kuo-kuang Road, Taichung 402, Taiwan.
Ultrason Sonochem. 2013 Jan;20(1):546-52. doi: 10.1016/j.ultsonch.2012.05.009. Epub 2012 May 24.
Ultrasonic assistance of lipase (Candida antarctica; Novozym® 435) catalyzed synthesis of 4'-acetoxyresveratrol from resveratrol and vinyl acetate was investigated. Response surface methodology and a three-level-three-factor Box-Behnken design were adopted to evaluate the effects of synthesis variables, including reaction time (4-12h), enzyme amount (2500-4500PLU), and ultrasonic power (90-150 W) on the percentage molar conversion of 4'-acetoxyresveratrol. Based on ridge max analysis, the optimum conditions for synthesis were: reaction time 10.78 h, enzyme amount 5492PLU, and ultrasonic power 147.8 W. With ultrasound assistance, not only the phenolic compound acetylation time decreased, but also a high yield (95.2%) was achieved. The reaction kinetic model agreed with Ping-Pong mechanism, and the apparent kinetic constant V(m)(')/K(2) ratio related to enzyme performance was 2.4 times higher in the ultrasound-assisted reaction than in the mechanical-mixing reaction. The apparent kinetic constant K(2) indicated that ultrasound enhanced the vinyl acetate affinity to the enzyme. The simplified Ping-Pong kinetic model was employed to simulate 4'-acetoxyresveratrol production in batch reaction. It was found that a good prediction existed between the fitting results and the experimental data.
超声辅助脂肪酶（南极假丝酵母；诺维信 435）催化白藜芦醇和醋酸乙烯酯合成 4'-乙酰氧基白藜芦醇。采用响应面法和三水平三因素 Box-Behnken 设计，考察了反应时间（4-12 h）、酶用量（2500-4500 PLU）和超声功率（90-150 W）等合成变量对白藜芦醇摩尔转化率的影响。基于脊最大值分析，合成的最佳条件为：反应时间 10.78 h，酶用量 5492 PLU，超声功率 147.8 W。超声辅助不仅缩短了酚类化合物的乙酰化时间，而且还获得了较高的产率（95.2%）。反应动力学模型符合乒乓机制，超声辅助反应中与酶性能相关的表观动力学常数 V(m)(')/K(2) 比值比机械搅拌反应高 2.4 倍。表观动力学常数 K(2)表明超声增强了醋酸乙烯酯与酶的亲和力。采用简化的乒乓动力学模型模拟间歇反应中 4'-乙酰氧基白藜芦醇的生产。发现拟合结果与实验数据之间存在良好的预测。
