文献类型：期刊文献

英文题名：Study of Vitamin C ester synthesis by immobilized lipase from Candida sp.

作者：Song, Qing-Xun[1]; Wei, Dong-Zhi[1]

机构：[1] State Key Laboratory of Bioreactor Engineering, Institute of Biochemistry, East China University of Science and Technology, Shanghai 200237, China

年份：2002

卷号：18

期号：4-6

起止页码：261

外文期刊名：Journal of Molecular Catalysis B: Enzymatic

收录：EI(收录号：2002477218144)

语种：英文

外文关键词：Enzyme immobilization - Enzymes - Esters - Ethanol - Infrared spectroscopy - Mass spectrometry - Molecular sieves - Nuclear magnetic resonance spectroscopy - Organic solvents - Synthesis (chemical)

摘要：Oleoyl ester of L-ascorbic acid was synthesized by using immobilized lipases from Candida sp. A series of solvents, such as ethanol, tetrahydrofuran, pyridine, butanol, tertiary amyl alcohol (t-amyl alcohol), hexanol, octanol and hexane (logP from -0.24 to 3.5) were investigated for the reaction, and t-amyl alcohol was found to be the most suitable from the standpoint of the substrate concentration and the enzyme activity. And the equilibrium of the reaction was affected by the addition of the molecular sieves and the temperature. Reaction carried out at 55°C and with 50g/l of 4? molecular sieves is good for the enzyme to keep its activity and for making the equilibrium go to the product. The kinetic model was studied and the result showed that the reaction can be described by Ping-Pong mechanism. Parameters value of Vm and K′m were obtained. Last, the pure products of the reaction were attained and determined by IR spectra, mass spectrometry and 1H NMR spectra. ? 2002 Elsevier Science B.V. All rights reserved.