Preparation of mussel-inspired porous magnetic materials for application in immobilized lipase

In this study, a porous composite material based on magnetic chitosan was prepared for lipase immobilization by applying a polydopamine coating on its surface instead of the traditional cross-linking agent. The material had excellent pore structure and large specific surface area, with a pore volume of 0.6028 mL/g and a specific surface area of 106.8239 m²/g, and the highest enzyme activity of the immobilized lipase could reach up to 7392.91±121.22 U/g-carrier. In addition, the enzymatic properties of the immobilized enzyme were investigated, and the optimal reaction temperature and pH were 50 ℃ and 7.0, respectively. Furthermore, the prepared immobilized enzyme exhibited good thermal and pH stabilities, and could maintain above 80% of the initial enzyme activity by the immobilized enzyme after five cycles of reuse, while 52% of the initial enzyme activity could be still maintained after ten cycles of reuse. Finally, the immobilized enzyme was applied in biodiesel conversion and the process was optimized.