Magnetized poly(STY-co-DVB) as a matrix for immobilizing microbial lipase to be used in biotransformation

Abstract

Magnetized hydrophobic polymeric particles were prepared by suspension polymerization of styrene and divinylbenzene with the addition of magnetite (Fe3O4) functionalized with oleic acid (OA). The magnetic poly(STY-co-DVB) particles were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the magnetic polymer particles fulfill the requirements for being used as matrix in the immobilization of microbial lipase from Candida rugosa by physical adsorption. The resulted immobilized derivative presented high catalytic activity in both aqueous and non-aqueous media. A comparative study between free and immobilized lipases showed a similar biochemical behavior, but with better hydrolytic activity at a pH range of 8.0–8.5. The patterns of heat stability indicated that the immobilization process also stabilizes the enzyme by a 50-fold improvement of thermal stability parameters (thermal deactivation and half-life time). Data on olive oil hydrolytic activities indicated that the Michaelis–Menten equation can be used to adjust data so as to calculate Km and Vmax, which attained values of 1766mM and 5870µMg−1min−1, respectively. Such values indicated that the immobilized system was subjected to mass transfer limitations. High operational stability (t ½=1014h) was achieved under repetitive batch runs in ester synthesis. The results indicated that the magnetized support particles can be very promising carriers for immobilizing enzymes in biotransformation reactions.