This study reported the modification of phosphatidylcholine (PC) with n-3 polyunsaturated fatty acids (PUFA)-rich ethyl esters (EE) by immobilized MAS1 lipase-catalyzed transesterification in the solvent-free system. Effects of n-3 PUFA-rich EE/PC mass ratio, enzyme loading, reaction temperature, and water dosage on the incorporation of n-3 PUFA into PC were investigated, respectively. The results indicate that the maximum incorporation of n-3 PUFA into PC reached 33.5% (24 h) under the following conditions: n-3 PUFA-rich EE/PC mass ratio of 6:1, enzyme loading of 20%, reaction temperature of 55 °C, and water dosage of 1.0%. After 72 h of reaction, the incorporation of n-3 PUFA into PC was 43.55% and the composition of the reaction mixture was analyzed by 31P nuclear magnetic resonance (NMR). The results show that the reaction product consisted of 32.68% PC, 28.76% 1-diacyl-sn-glycero-3-lysophosphatidylcholine (sn-1 LPC), 4.90% 2-diacyl-sn-glycero-3-lysophosphatidylcholine (sn-2 LPC), and 33.60% sn-glycero-3-phosphatidylcholine (GPC). This study offers insight into the phospholipase activity of immobilized MAS1 lipase and suggests the extended applications of immobilized MAS1 lipase in the modification of phospholipids for industrial purpose.
Keywords: ethyl esters; immobilized MAS1 lipase; n-3 polyunsaturated fatty acids; phosphatidylcholine; transesterification.