Immobilization of Phospholipase D on Silica-Coated Magnetic Nanoparticles for the Synthesis of Functional Phosphatidylserine

In this study, silica-coated magnetic nanoparticles (Fe3O4/SiO2) were synthesized and applied in the immobilization of phospholipase D (PLDa2) via physical adsorption and covalent attachment. The immobilized PLDa2 was applied in the synthesis of functional phosphatidylserine (PS) through a transphophatidylation reaction. The synthesis process and characterizations of the carriers were examined by scanning electron microscope (SEM), transmission electron microscope (TEM), and Fourier-transform infrared spectroscopy (FT-IR). The optimum immobilization conditions were evaluated, and the thermal and pH stability of immobilized and free PLDa2 were measured and compared. The tolerance to high temperature of immobilized PLDa2 increased remarkably by 10 degrees C. Furthermore, the catalytic activity of the immobilized PLDa2 remained at 40% after eight recycles, which revealed that silica-coated magnetic nanoparticles have potential application for immobilization and catalytic reactions in a biphasic system.