关键词: 纳米磁性载体, 脂肪酶, 固定化

Abstract: Lauric acid-stabilized magnetic nanoparticles were prepared and used for enzyme immobilization. The Fe3O4 magnetic nanoparticles were characterized by transmission electron microscopy and magnetic measurements. The observations indicated that the particles were superparamagnetic. Magnetic sedimentation of the nanoparticles was achieved within 0.6 min in organic solution, 200 times faster than the gravitational sedimentation. Lauric acid provided a hydrophobic interface to the immobilized lipase, and the conformational changes induced by interacting with the hydrophobic interface yielded an "open structure" of the lipase. CRL was immobilized to the magnetic carrier with a specific activity of 718 U/g, 1.8 times higher than the free lipase containing the same protein quantity. The pH dependencies of the immobilized and free lipases were investigated and the optimum pH for them were determined. Moreover, activity amelioration and stability of the immobilized lipase for the hydrolysis of olive oil was observed.

Key words: magnetic nanoparticles, lipase, immobilization