Preparation and Kinetic Study of CoFe2O4@silica@ROL Nanobiocatalyst

Magnetic nanoparticles such as CoFe2O4, with their special properties such as higher specific surface area for loading of a large amount of an enzyme, nontoxicity and biocompatibility, and ease of separation from a reaction mixture applying a magnetic field are attractive substrate to immobilize lipase enzymes as extremely valuable biocatalysts for many practical/industrial applications. Lipases have been used in pharmaceutical industry and production of fine chemicals and even biofuel. Employing lipases requires a full recycling of these enzymes to optimize economic benefits and minimize waste disposal for industrial purposes which could be accomplished using magnetic nanoparticles as immobilization substrates. Therefore, the aim of this work was to prepare silica coated magnetic substrates to immobilize Rhizopus oryzae lipase (ROL) and study the kinetic parameters of this novel nano biocatalyst. At first, CoFe2O4 nanoparticles were synthesized using a co-precipitation method followed by coating with silica. Afterwards, the nanoparticles were functionalized with amine groups. Lipase was then directly immobilized onto the modified nanoparticles through a covalent interaction. Enzyme activity was assessed by measuring catalytic hydrolysis of p-nitrophenyl butyrate. The catalytic constant, kcat, and the catalytic efficiency, kcat/Km, increased 1.05 and 0.854 times, respectively, after immobilization.