Shape-controlled synthesis of Fe sub(3)O sub(4)/CeO sub(2 ) hybrid octahedra for lipase immobilization

Fe sub(3)O sub(4)/CeO sub(2) hybrid octahedra have been successfully synthesized on the large scale viaa solvothermal route, which were confirmed by a series of modern analytical tools. The formation and evolution of Fe sub(3)O sub(4)/CeO sub(2 ) hybrid octahedra were systematically investigated, and a kinetically induced anisotropic growth mechanism clearly contributes to the formation of the novel architecture. Because of the magnetic nature and unique surfaces, the as-prepared Fe sub(3)O sub(4)/CeO sub(2 ) hybrid octahedra were employed as magnetic carriers for lipase immobilization. Our results indicated that the lipase loading amount on the magnetic Fe sub(3)O sub(4)/CeO sub(2 ) nanoparticles was about 43.1 mg of protein per g. Hydrolytic activity tests revealed that the immobilized lipase retains about 92.4% of the free enzyme's activity. The reusability assay revealed that the immobilized lipase can be reused 3 times without marked loss of catalytic activity (