Investigation into the magnetic immobilization of lipase and its application in the synthesis of structured triacylglycerols
Yue Peng, Minghao Wang, Xi Huang, Fuming Yang, Yongge Shi, Changbao Liao, Dianyu Yu
Abstract
In this paper, sn-1,3-specific lipase from Rhizomucor miehei (RML) was immobilized with dialdehyde starch (DAS) as a support activating agent and nano-sized Fe3O4 as a magnetic carrier. The structured triacylglycerol as human milk fat substitutes enriched with OPO was produced. The results showed that the fixed load of lipase was 52.41 mg/g. The enzyme activity recovery was 57.82%. Compared with free lipase, the relative enzyme activity of RML immobilized in magnetic particle was kept at 92% when placing 10 h in a methanol solution. The lipase immobilized in magnetic particle had an average particle diameter of 169 nm and was applied in the synthesis reaction of 1,3-dioleoyl-2-palmitoylglycerol (OPO) by using tripalmitin (PPP) and oleic acid (OA) as raw materials. Under the optimal reaction conditions of 10% immobilized lipase, 5:1 substrate molar ratio (OA/PPP), 50 °C reaction temperature and 7 h reaction time, the product's OPO content was 43.97%, and the content of triacylglycerols rich in palmitic acid at the sn-2 position was 83.32%. After eight repeated uses at 50 °C, the relative activity of RML immobilized in magnetic particle remained above 71%. The synthesized OPO has potential to be used in infant formulas.