Development of a Superparamagnetic Laccase Nanobiocatalyst for the Enzymatic Biotransformation of Xenobiotics

Abstract

The development of nanotechnology has provided a range of diverse nanoscale carriers that can be potentially applied for enzyme immobilization. Among the different types of support, magnetic nanoparticles (mNPs) have received increasing attention because they can be easily recovered from the reaction medium by applying an external magnetic field. In the present study, silica-coated magnetic nanoparticles (Fe3O4@SiO2) were prepared, characterized, and used for covalent immobilization of laccase from Trametes versicolor. Different concentrations of the functionalization agent (3-aminopropyltriethoxysilane), cross-linker (glutaraldehyde), and laccase allowed a maximum enzyme loading of 2.68±.8 U mg−1 mNP. Several factors, including pH, T, presence of inactivating compounds, enzyme stability, and reusability of the support, were evaluated. The oxidative action of the enzyme toward xenobiotics was proven in the formation of the chromogenic radical of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and the biotransformation of the endocrine-disrupting compound Bisphenol A (BPA). The enhancement of catalytic activity and stability of the nanobiocatalyst was evidenced by the increase of ABTS oxidation. Moreover, the superparamagnetic characteristic of the support allowed simple and fast recovery of the nanobiocatalyst. With the development of nanobiocatalyst-driven applications in mind, the development of magnetic nanoparticle synthesis at large scale as well as the design of bioreactors that assure the retention and recovery of the nanobiocatalyst need to addressed.