Synthesis of amine-functionalized Fe3O4@C nanoparticles for lipase immobilization

Amine-functionalized Fe3O4@C nanoparticles have been successfully synthesized on a large scale via a solvothermal route. The morphology, structure and properties of the Fe3O4@C nanoparticles were investigated through different analytical tools. Due to the magnetic nature and the presence of amine-functionalized groups, the as-prepared Fe3O4@C nanoparticles were employed as magnetic carriers for lipase immobilization. Our results indicate that the lipase loading amount on the magnetic Fe3O4@C nanoparticles was about 115.6 mg of protein per g. The factors related to the catalytic activity of the immobilized lipase on the magnetic carriers were systematically investigated. Hydrolytic activity tests reveal that the immobilized lipase retains about 93% of the free enzyme activity. It should be mentioned that the thermal stability of the immobilized lipase was strikingly higher than that of the free lipase. Most importantly, the immobilized lipase retained more than 68% of its initial activities after 10 times reuse. It is hoped that the amine-functionalized Fe3O4@C nanoparticles may find an application in biotechnology and catalysis.