IMMOBILIZATION OF LACCASE ENZYME ON GREEN-SYNTHESIZED ZINC OXIDE NANOPARTICLES FOR BIOCATALYTIC AND ANTIBACTERIAL APPLICATIONS

Abstract

The immobilization of enzymes on nanomaterials offers a sustainable route to enhance catalytic efficiency and stability. In this study, zinc oxide nanoparticles (ZnO NPs) were synthesized via a green route using plant leaf extract and employed for the immobilization of laccase, a versatile biocatalyst. The synthesized ZnO NPs were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), confirming their crystalline structure, nanoscale size, and high surface area suitable for enzyme attachment. The immobilized laccase exhibited enhanced catalytic performance, retaining over 80% of its initial activity after five consecutive reuse cycles, along with improved thermal and pH stability compared to the free enzyme. Furthermore, the laccase–ZnO nanocomposite displayed notable antibacterial activity against Escherichia coli and Staphylococcus aureus, indicating its potential as a dual-function biocatalyst and antimicrobial agent. This eco-friendly nanobiocatalyst highlights a sustainable strategy for applications in wastewater treatment, biosensing, and antimicrobial interventions, integrating principles of green chemistry with advanced nanobiotechnology. Overall, the study demonstrates the effectiveness of green-synthesized ZnO NPs in enzyme immobilization, offering a promising platform for industrial and environmental biotechnological applications.