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采用脂肪酶Novozyme 435催化月桂酸甲酯与甘油进行酯交换反应制备单月桂酸甘油酯。以反应体系中单月桂酸甘油酯的质量分数为考察指标,通过单因素实验和正交实验对酶催化合成工艺进行优化,得到最佳的工艺条件为:底物摩尔比n(月桂酸甲酯)∶n(甘油)=1∶5,底物质量分数为20%(即月桂酸甲酯与叔丁醇的质量百分数,下同),反应温度为55℃,酶添加量为7%(即酶与月桂酸甲酯的质量百分数,下同),初始含水量为20%(以月桂酸甲酯质量计,下同),转速为100 r/min,反应时间为1 h,在该条件下,体系中单月桂酸甘油酯的质量分数为71.86%。经提纯后终产物中单月桂酸甘油酯的质量分数高于95%,最高可达98.76%,而双月桂酸甘油酯的质量分数低于5%。酶重复使用6次,单月桂酸甘油酯的质量分数从71.75%降至68.36%,其催化性能无显著降低。
Glycerol monolaurate was prepared by transesterification of methyl laurate and glycerol with lipase Novozyme 435. Based on the mass fraction of glycerol monolaurate in the reaction system, the optimal conditions for the synthesis of the enzyme catalyzed by single factor experiments and orthogonal experiments were as follows: substrate molar ratio n (methyl laurate ): N (glycerol) = 1: 5, the mass fraction of the substrate is 20% (mass percentage of methyl laurate and t-butyl alcohol, the same below), the reaction temperature is 55 ℃, The mass percentage of the enzyme and the methyl laurate, the same below), the initial water content of 20% (methyl laurate mass, the same below), speed of 100 r / min, the reaction time was 1 h, under the conditions The mass fraction of monolaurin in the system was 71.86%. After purification, the mass fraction of monolaurin in the final product is higher than 95%, up to 98.76%, while the content of glycerol monolaurate is less than 5%. Repeated enzyme 6 times, monolaurin mass fraction decreased from 71.75% to 68.36%, the catalytic performance was not significantly reduced.