月桂酸甘油二酯和豆蔻酸甘油二酯的固定化脂肪酶R IM-03催化合成及纯化

Synthesis of laurate-diglyceride and myristate-diglyceride catalyzed by immobilized lipase R IM-03 and their purification

为促进固定化脂肪酶R IM-03在合成甘油二酯(DAG)中的应用,采用固定化脂肪酶RIM-03催化月桂酸/豆蔻酸和甘油酯化合成甘油二酯,并采用分子蒸馏对其进行纯化。对酯化反应和分子蒸馏的工艺条件进行了优化,并考察了纯化产物的理化性质。结果表明:固定化脂肪酶R IM-03催化甘油和月桂酸/豆蔻酸合成甘油二酯的最优条件为底物(脂肪酸与甘油)物质的量比2∶1、反应温度60℃、反应时间6h、酶添加量6%(以底物质量计),在此条件下月桂酸甘油二酯和豆蔻酸甘油二酯粗产物中甘油二酯含量分别为43.87%和30.00%,甘油三酯(TAG)含量分别为8.71%和6.87%,催化剂可重复利用至少10次;月桂酸甘油二酯粗产物纯化的最优条件为一级分子蒸馏温度170℃、二级分子蒸馏温度180℃,豆蔻酸甘油二酯粗产物纯化的最优条件为一级分子蒸馏温度170℃、二级分子蒸馏温度190℃,在最优条件下纯化月桂酸甘油二酯和豆蔻酸甘油二酯中甘油二酯含量分别达81.29%和80.08%,1,3-甘油二酯含量分别为53.16%和54.27%,DAG/(DAG+TAG)约为80%;纯化月桂酸甘油二酯和豆蔻酸甘油二酯的滑动熔点分别为48.9℃和57.0℃,在30~40℃区间的固体脂肪含量呈陡然下降趋势,在两者复配的体系中,当豆蔻酸甘油二酯占60%以上时,相容性理想。综上,固定化脂肪酶RIM-03具有在甘油二酯合成中应用的潜力,DAG/(DAG+TAG)可作为关键控制指标,异酸甘油二酯复配可改变产物的熔化性质。

In order to promote application of immobilized lipase R IM-03 in synthesis of diacylglycerols(DAG),laurate-diglyceride and myristate-diglyceride were synthesized by immobilized lipase R IM-03 catalysis,and purified with molecular distillation.The processing conditions of esterification and molecular distillation were optimized,and the physicochemical properties of the purified diacylglycerols were evaluated.The results showed that the optimal conditions for the synthesis of diacylglycerols from glycerol and lauric acid or myristic acid catalyzed by immobilized lipase R IM-03 were as follows:molar ratio of substrate(fatty acid to glycerol)2∶1,reaction temperature 60℃,reaction time 6 h,and enzyme addition amount 6%(based on the mass of substrate).Under these conditions,the content of laurate-diglyceride and myristate-diglyceride in the crude products were 43.87%and 30.00%,respectively,and the contents of triacylglycerol(TAG)were 8.71%and 6.87%,respectively.The catalyst could be reused at least 10 times.The optimal conditions for purification of laurate-diglyceride were as follows:the primary molecular distillation temperature 170℃,and the secondary molecular distillation temperature 180℃.The optimal conditions for purification of myristate-diglyceride were as follows:the primary molecular distillation temperature 170℃,and the secondary molecular distillation temperature 190℃.Under these conditions,the contents of diacylglycerols in purified laurate-diglyceride and myristate-diglyceride reached 81.29%and 80.08%,respectively.The contents of 1,3-diacylglycerols were 53.16%and 54.27%respectively,and the DAG/(DAG+TAG)was about 80%.Slip melting points of the purified laurate-diglyceride and myristate-diglyceride were 48.9℃and 57.0℃,respectively,and the solid fat content showed a steep decline at 30-40℃.In the mixing system of the two diacylglycerols,when the myristate-diglyceride content was more than 60%,the compatibility was desirable.In conclusion,immobilized lipase R IM-03 exhibits potential application in synthesis of diacylglycerol.DAG/(DAG+TAG)can be used as a key control index,and the melting property of the product can be changed by combination of different fatty acid-diglyceride.