响应面法优化脂肪酶催化合成单、双甘酯的工艺研究

Response Surface-Optimized Process of Monoglycerides and Diacylglycerols by Lipase-Catalyzed Esterification

利用响应面法对无溶剂体系中假丝酵母99-125脂肪酶-β环糊精复合物催化甘油、油酸酯化反应合成单甘酯、双甘酯的反应条件进行了优化。选取催化剂添加量、醇酸物质的量比、搅拌转速、反应初始加水量、β-环糊精添加量、温度等6个因素作为连续变量,反应时间作为不确定变量进行中心组份星型设计,以单甘酯、双甘酯、三甘酯、脂肪酸为响应值设计出47个实验并进行了模型分析,确定了单甘酯、双甘酯的最佳反应条件以及影响反应的关键因素。分析结果表明,在各影响因素中,醇酸物质的量比和反应初始加水量对单甘酯和双甘酯的含量影响最大,优化后单双甘酯含量均可达40%左右,单双甘酯总量达60%以上,均与响应面模型预测值吻合。利用该模型可有效控制反应过程中单、双甘酯的比例。

The esterification of glycerol and oleic acid catalyzed by lipase Candida sp 99-125 was optimized through the response surface methodology （RSM） for synthesis of MAG and DAG in solvent-free system. A 3-1evel-7-factor central composite face design （CCFD） was employed to evaluate the effects of catalyst load, molar ratio of glycerol to oleic acid, agitator speed, initial water content, mass ratio of fl-cyclodextrin to lipasereaction temperature and reaction time, among which the reaction time was uncontrolled variable and the others was controlled variables. The results showed that the molar ratio of glycerol to oleic acid and initial water content were the most significant factors to the reaction. Under the optimal conditions, about 40% MAG or DAG was obtained, and the total yield of MAG and DAG were above 60%. Predicted values showed good validation with the experimental values when experi,nents corresponding to selected points on the contour plots were carried out. Proportion of MAG and DAG in the reaction can be well controlled using the model.