Improved Catalytic Performance of Aspergillus flavus Laccase Immobilized on the Zinc Ferrite Nanoparticles

In this study, zinc ferrite nanoparticles have been synthesized by co-precipitation method and used as carrier for the immobilization of Aspergillus flavus laccase. Identification of functional groups, crystallinity and morphological behavior of zinc ferrite particles was done by using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy, respectively. Synthesized particles were activated by glutaraldehyde and enzyme was immobilized via covalent adsorption. The maximum laccase loading was achieved with 40 mg/100 mg of support and 6 hours of incubation period. Immobilized laccase displayed high immobilization yield and apparent activity i.e. 89.6% and 70% respectively. The pH and temperature optima for the free and immobilized enzymes were observed to be same, however, immobilized laccase exhibited significantly higher relative activities at broader pH and temperature ranges compared to free enzyme. Immobilization of enzyme resulted in improved thermo-stability with significantly higher half-lives (i.e., 1.25–2 folds) at different temperatures. Moreover, after ten cycles of reuse the Immobilized laccase retained about 82% of its initial activity. Overall, it is revealed that laccase immobilization on zinc ferrite nano-particles has various potential characteristics making it a promising candidate for the utilization in various chemical processes. Graphical Abstract