Immobilization of Laccase Enzyme on Silica-Coated Iron Oxide Nanoparticles and Comparison of Stability and Activity of Free and Immobilized Laccase

  Laccase enzyme is capable of oxidizing many resistant and non-biodegradable environmental pollutants, so it has been studied frequently in recent years and is widely used in biodegradation of contaminants. Despite its abundant applicability, due to its short life span, nonrecovery, thermal instability and instability in organic environments, its widespread use is very limited.
The present study aimed to increase the stability of laccase by immobilizing it on silica coated iron oxide nanoparticles. Fe3O4 nanoparticles were synthesized based on the co-precipitation method and after coating with silica, their surface was modified by amine groups. The enzyme was then immobilized by covalent binding using glutaraldehyde. Specifications of synthesized nanoparticles and immobilized enzyme were investigated using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and Energy-dispersive X-ray spectroscopy
(EDX). Results of successful laccase immobilization on nanoparticles showed that laccase immobilization significantly increased storage and thermal stability, maintaining activity in a wider
range of temperature and pH than free laccase. The immobilization of laccase on silica-coated iron oxide nanoparticles can reduce the barriers and challenges of various enzymes by increasing its efficiency and stability.