以甘油和PUFA乙酯为底物,通过酶催化酯交换反应合成富含DHA、EPA的甘油三酯.首先以叔丁醇为溶剂合成甘油酯混合物,优化后的条件为:选择Novozyme 435脂肪酶为催化剂,反应温度50℃,甘油与PUFA乙酯摩尔比1:3,底物在叔丁醇中的质量浓度为200g/L,酶加量为底物质量的2%,在此条件下反应12 h后PUFA乙酯的转化率可达到51.5%.将在此条件下得到的反应混合物除去叔丁醇,在真空条件下继续反应24 h,PUFA乙酯转化率可达到87.8%.得到的产品混合物甘油酯组成为:甘油三酯67.1%,甘油二酯18.2%,甘油单酯2.1%.%The synthesis of triacylglycerols riched in DHA and EPA from PUFA ethyl ester and glycerol was studied. The developed process consisted of two steps: ( 1 ) the glycerolysis reaction was carried out by using tert -butyl alcohol as a solvent and Novozyme 435 as a catalyst. The best results (51.5％ conversion of PUFA ethyl ester) were obtained at the conditions of 50 ℃, molar ratio of glycerol to PUFA ethyl ester 1∶3, substrate concentration in tert - butyl alcohol 200 g/L, 2％ Novozyme 435 ( based on the mass of substrates) , and reaction time 12 h. (2) The reaction product in the first step was separated to remove the tert - butyl alcohol,and further conducted glycerolysis for 24 h under vacuum, and the conversion rate of PUFA ethyl ester reached 87.8％, and the compositions of the finished product were 67.1％ triacylglycerols, 18.2％ diacylglycerols and 2.1％ monoacylglycerols.
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