Immobilized lipase on core-shell structured Fe3O4-MCM-41 nanocomposites as a magnetically recyclable biocatalyst for interesterification of soybean oil and lard.

A core-shell structured Fe3O4-MCM-41 nanocomposite was prepared by means of a surfactant-directed sol-gel process. Candida rugosa lipase was then bound to the magnetic core-shell material by using glutaraldehyde as a cross-linking reagent. The as-prepared Fe3O4-MCM-41 support and the immobilized lipase were characterized in detail using enzyme activity assays, TEM, XRD, FTIR, VSM and nitrogen adsorption-desorption techniques. Results showed that the magnetite nanoparticles were coated with the MCM-41 silica with the formation of core-shell structured materials, and the lipase was successfully immobilized on the core-shell structured support. The catalytic performance of the bound lipase was tested in the interesterification of lard and soybean oil. It was shown that the immobilized lipase had a better catalytic activity towards the interesterification reaction. The slip melting point of the final product was lower than that of the original blend, and the interesterification led to an obvious variation in the microstructure of the product.