A novel method for improving laccase activity by immobilization onto copper ferrite nanoparticles for lignin degradation.

In this paper, a novel method for simultaneous enhancement of catalytic activity and reusability of laccase was carried out to overcome the limitations on industrial application of laccase. The immobilization of laccase onto copper ferrite magnetic nanoparticles (CuMNPs) and ferrite magnetic nanoparticles (MNPs) were optimized at 50 mM glutaraldehyde concentration and 1:5 enzyme:nanoparticles (NPs) ratio for 9 h of cross-linking time, yielding a maximum activity recovery of 94.68 ± 0.92% and 89.78 ± 1.24%, respectively. The laccase immobilized NPs were characterized using physico-chemical methods such as SEM-EDAX, FTIR, XRD, TGA and VSM and the laccase immobilized CuMNPs showed 18% higher activity as compared to free enzyme. The prepared CuMNPs and MNPs showed superior thermal stability (50-70 °C) with t1/2 increased by 5.7 and 4.1 folds, respectively, as compared to free laccase. The laccase in immobilized forms exhibited higher kinetic potential and stable at wide temperature and pH range. In addition, laccase immobilized NPs retained more than 70% residual activity during reuse up to 6 cycles and storing for 20 days at 4 °C. The laccase immobilized CuMNPs showed higher delignification (43.28 ± 1.46%) on Ipomoea carnea than laccase immobilized MNPs.