초록
This study reported that immobilized MAS1 lipase showed high catalytic efficiency in the production of triacylglycerols (TAG) highly enriched with n-3 polyunsaturated fatty acids (PUFA) by glycerolysis of ethyl esters (EE). Immobilized MAS1 lipase was found to have no regiospecificity and be a more suitable catalyst for the glycerolysis of n-3 PUFA-rich EE compared with other enzymes. Higher TAG content (73.9%) and EE conversion (82%) were obtained by immobilized MAS1 lipase than those by Novozym 435 (29.6% and 54.8%, respectively) and Lipozyme RM IM (10% and 49%, respectively). Besides, the effects of temperature, enzyme loading and n-3 PUFA-rich EE/glycerol molar ratio on TAG content were evaluated using response surface methodology. The results showed that temperature, enzyme loading and n-3 PUFA-rich EE/glycerol molar ratio had significant effects on TAG content. The maximum TAG content (76.5%) was achieved under the optimal conditions (enzyme loading of 163.8U/g substrate, n-3 PUFA-rich EE/glycerol molar ratio of 4.13:1 at 65<SUP>o</SUP>C). Subsequently, the glycerolysis reaction mixtures were further purified by molecular distillation and highly pure n-3 PUFA-rich TAG (96.2%) with similar fatty acids composition to the substrate (EE) was obtained in the final products. In addition, the obtained final products had low acid value and peroxide value (0.03mg KOH/g and 3.2meq/kg, respectively). These results indicated that immobilized MAS1 lipase is a promising catalyst for the synthesis of TAG in industrial application.