非水体系中脂肪酶催化合成乳酸乙基糖苷酯的工艺研究

在非水体系中 ,通过固定化脂肪酶催化合成一种新型α 羟基酸衍生物 乳酸糖苷酯。考察了常压下有机溶剂、酰基供体、不同种固定化酶、乙基糖苷的浓度、酶量和反应温度对反应的影响。研究表明在无溶剂体系中以乳酸丁酯作为酰基供体可有效地合成乳酸糖苷酯 ,固定化酶Novozym435和来源于Candida sp .菌株的细胞固定化酶 ,化学修饰的干酶粉均是合适的催化剂。最佳反应条件为 :酶浓度 75g L ,乙基葡萄糖苷的浓度为 0.4mol L ,温度为 70℃ ,转速 200r min ,反应 50h ,转化率可达 71%。在真空度为 0.09MPa的压力下 ,反应温度 65℃ ,酶浓度 75g L ,乙基葡萄糖苷 0.35mol L时 ,反应初速率可达到 607(mmol·L^-1·h^-1 ) ,40h后转化率可达到 90%。反应产物经过萃取法和硅胶柱层析方法分离 ,纯度达到 95 % (W/W)。

Studies on Lipase-catalyzed Synthesis of Ethylglucoside Lactate in Non-aqueous Phase

Ethylglucoside lactate, a novel Alpha-Hydroxy Acids Derivative, was synthesized by transesterification in non-aqueous phase using immobilized lipase as biocatalyst. Based on the studies of the factors effecting initial rate and conversion under atmospheric pressure (solvent, acyl donor, different immobilized lipase, substrate concentration, enzyme concentration and temperature), the results show that solvent-free medium using butyllactate as acyl donor is suitable to the ester synthesis. The reaction conditions have been optimized as the following: the amount of enzyme = 75 g/L, the ethylglucoside concentration = 0.4 mol/L, 70 degrees C, 200 r/min, 50 h, which the conversion was 71%. A 90% conversion and a 60.7 mmol.L-1.h-1 initial rate can be obtained under reduced pressure, which the conditions are enzyme 75 g/L, ethylglucoside 0.35 mol/L, 65 degrees C, 200 r/min and 40 h. The product purified by extraction and SIO2 chromatography was identified by infrared spectroscopy and 1H NMR.