Influence of water activity and water content on sugar esters lipase-catalyzed synthesis in organic media
Influence of water activity and water content on sugar esters lipase-catalyzed synthesis in organic media
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DOI：
10.1016/s1381-1177(00)00166-1
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发表时间：
2001-01-22
影响因子：
--
通讯作者：
Ghoul, M
中科院分区：
文献类型：
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作者：
Chamouleau, F;Coulon, D;Ghoul, M
在有机介质中，脂肪酶催化酯键的合成受反应混合物的热力学水活度的指导。考察了水分活度和含水量对南极假丝酵母脂肪酶催化合成棕榈酸果糖的影响。分析了转化率、合成初速率和反应选择性。通过用饱和盐溶液预平衡将反应介质的初始水活度固定在所需值。C.脂肪酶活性强烈依赖于初始水活度值。转化率和初始速率随水活度的增加而降低。无论α值如何，果糖双棕榈酸酯仅被合成。对于初始水活度小于0.07的反应介质，获得了最好的结果。在此条件下，28.5%的果糖在果糖双棕榈酸酯中酰化，初始速率为4.9 g 1（-1）h（-1）。为了改进该方法，通过用分子筛干燥介质来确定水的作用。果糖转化率和果糖双棕榈酸酯合成起始速率分别提高到73.4%（32 g1（-1））和10.1g1（-1）h（-1）。然而，干燥介质的使用影响反应的选择性。在这些条件下，单-和二-果糖棕榈酸酯合成（16.7克1（-1））。(C)2001 Elsevier Science B.V，保留所有权利。
Lipase-catalysed ester bond synthesis in organic media was directed by thermodynamic water activity of the reaction mixture. The effects of water activity and water content were investigated with fructose palmitate synthesis catalysed by Candida antarctica lipase. Conversion yield, initial rate of synthesis and reaction selectivity were analysed. Initial water activity of the reaction medium was fixed at a desired value by pre-equilibration with saturated salt solutions. C. antarctica Lipase activity depended strongly on initial water activity value. Conversion yield and initial rate decreased with the increase of water activity. Whatever the a, value, fructose monopalmitate was only synthesised. The best results were achieved for a reaction medium with an initial water activity less than 0.07. In these conditions, 28.5% of fructose was acylated in fructose monopalmitate with an initial rate of 4.9 g 1(-1)h(-1). To improve the process, the effect of the water was determined by drying the medium with molecular sieves. Conversion yield of fructose and initial rate of fructose monopalmitate synthesis were raised, respectively, to 73.4% (32 g 1(-1)) and 10.1 g 1(-1) h(-1). However, the use of dried medium affected the selectivity of the reaction. In these conditions, both mono- and di-fructose palmitate were synthesised (16.7 g 1(-1)). (C) 2001 Elsevier Science B.V, All rights reserved.