Kinetic aspects of ultrasound-accelerated lipase catalyzed acetylation and optimal synthesis of 4'-acetoxyresveratrol.
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.
Biotechnology Center, National Chung Hsing University, 250 Kuo-kuang Road, Taichung 402, Taiwan.
Chia-Hung
CH
Kuo
Fang-Wen
FW
Hsiao
Jiann-Hwa
JH
Chen
Chang-Wei
CW
Hsieh
Yung-Chuan
YC
Liu
Chwen-Jen
CJ
Shieh
D000107:Acetylation; D055162:Biocatalysis; D002175:Candida / Q000201:enzymology; D007700:Kinetics; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D000077185:Resveratrol; D013267:Stilbenes / Q000138:chemical synthesis*; D014465:Ultrasonics
D013267:Stilbenes; D008049:Lipase; D000077185:Resveratrol