Immobilization of Pepsin on Chitosan Magnetic Nanoparticles and Its Application in Deacetylation of Amides

A core-shell composite of chitosan on Fe3O4 nanoparticles was successfully synthesized and pepsin enzyme was immobilized on it via imine linkages. The supported aspartic protease was characterized by IR spectroscopy and its morphology was studied by X-ray diffraction (XRD) analysis, as well as scanning electron microscopy (SEM) and transmission electron microscopy (TEM), confirming its spheroidal structure. Thermal analysis was carried out by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) methods, revealing its stepwise weight loss. The amounts of Fe3O4, chitosan and enzyme were measured to be 50, 40, and 10wt%, respectively. The deacetylation of various amides was prosperously accomplished by the immobilized pepsin at room temperature through the suggested mechanism, and the supported enzyme could be separated and reused for at least three cycles. The amount of immobilization was measured to be 99mg/g of support, and according to vibrating sample magnetometer (VSM) analysis, this magnetic nanocomposite could be proposed for biomedical applications.