Direct binding and characterization of laccase onto iron oxide nanoparticles

Abstract

Iron oxide nanoparticles exhibit unique magnetic properties and possess a high surface-to-volume ratio, making them ideal candidates for the conjugation of substances, including enzymes. Laccase (EC 1.10.3.2), an oxidative enzyme with diverse applications, presents an opportunity for enhancing stability and reusability through innovative immobilization techniques, thus reducing overall process costs. In this study, we employed a direct binding procedure via carbodiimide activation to conjugate laccase onto iron oxide nanoparticles synthesized using thermal chemical coprecipitation. Stabilization of the nanoparticles was achieved using thioglycerol and polyvinyl chloride as capping agents. Characterization of the synthesized nanoparticles was conducted using UV-spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Energy dispersive X-ray spectroscopy (EDS). FTIR spectroscopy analysis confirmed successful laccase binding to magnetic nanoparticles, with binding efficiencies of 90.65% and 73.02% observed for thioglycerol and polyvinyl chloride capped iron oxide nanoparticles, respectively. Furthermore, the conjugated enzyme exhibited remarkable stability, retaining nearly 50% of its initial activity after 20 reuse cycles. This research demonstrates that immobilizing laccase onto iron oxide nanoparticles enhances its activity, stability, and reusability, with the potential for significant cost savings and expanded applications in various fields.