Magnetic nanocomposite MnFe₂O₄-SiO₂ as an efficient carrier for phospholipase A1 in DHA-rich phosphatidylcholine synthesis

To address the instability and low reusability of free phospholipase A1 (PLA1) in enzymatic synthesis, this study introduces a magnetic nanocomposite, MnFe₂O₄-SiO₂, as an efficient carrier for enzyme immobilization. Synthesized through a hydrothermal method followed by silica coating, this advanced material boasts a high specific surface area, excellent magnetic separability, and robust structural integrity. These characteristics synergistically enhance the immobilization process, resulting in a remarkable 70% immobilization efficiency under optimized conditions. Notably, the immobilized enzyme exhibited significantly improved catalytic activity compared to its free counterpart. In the transesterification reaction, the system achieved impressive incorporation rates of 41.91% for docosahexaenoic acid (DHA) and 13.33% for docosapentaenoic acid (DPA). Furthermore, the immobilized enzyme demonstrated excellent operational stability, retaining 68.75% of its initial activity after five consecutive reaction cycles. This work demonstrates the potential of MnFe₂O₄-SiO₂ for sustainable and efficient enzyme catalysis, offering a scalable solution for the industrial production of DHA-rich phosphatidylcholine.