Facile preparation of magnetic carbon nanotubes-immobilized lipase for highly efficient synthesis of 1,3-dioleoyl-2-palmitoylglycerol-rich human milk fat substitutes

•A novel magnetically retrievable immobilized lipase was prepared.•OPO-rich TAGs was efficiently synthesized by enzymatic acidolysis.•The activity and reusability of CLL@mMWCNTs was superior to Lipozyme RM IM.•Production of OPO-rich TAGs was performed using lard and restructured palm oil.

In this study, Candida lipolytica lipase (CLL) was immobilized on magnetic multi-walled carbon nanotubes (mMWCNTs) via hydrophobic and cation-exchange interaction. The resultant immobilized CLL showed much better thermal stability, biocatalyst activity and easier recycling than the free form. A method for efficient enzymatic acidolysis of tripalmitin (PPP) with oleic acid (OA), to produce OPO-rich TAGs, was developed, using the immobilized CLL as the biocatalyst. Under optimized conditions (2% water, 20 mg/ml enzyme, 1:6 PPP/OA, 50 °C, 2 h), the content of OPO in the final product reached 46.5%. CLL@mMWCNTs had a better activity and manipulative stability than commercial lipases. More importantly, the feasibility of CLL@mMWCNTs was also validated in the practical production of OPO-rich TAGs, using lard and restructured palm oil as the raw material. These results suggest that CLL@mMWCNTs is a promising biocatalyst for the OPO-rich TAGs production and will be helpful for the infant formula industry.