Laccase Immobilization on Copper-Magnetic Nanoparticles for Efficient Bisphenol Degradation

Laccase activity is influenced by copper (Cu) as an inducer. In this study, laccase was immobilized on Cu and Cu-magnetic (Cu/Fe2O4) nanoparticles (NPs) to improve enzyme stability and potential applications. The Cu/Fe2O4 NPs functionally activated by 3-aminopropyltriethoxysilane and glutaraldehyde exhibited an immobilization yield and relative activity (RA) of 93.1 and 140%, respectively. Under optimized conditions, Cu/Fe2O4NPs showed high loading of laccase up to 285 mg/g of support and maximum RA of 140% at a pH 5.0 after 24 h of incubation (4oC). Immobilized laccase, as Cu/Fe2O4-laccase, had a higher optimum pH (4.0) and temperature (45oC) than those of a free enzyme. The pH and temperature profiles were significantly improved through immobilization. Cu/Fe2O4-laccase exhibited 25-fold higher thermal stability at 65oC and retained residual activity of 91.8% after 10 cycles of reuse. The degradation of bisphenols was 3.9-fold higher with Cu/Fe2O4- laccase than that with the free enzyme. To the best of our knowledge, Rhus vernicifera laccase immobilization on Cu or Cu/Fe2O4NPs has not yet been reported. This investigation revealed that laccase immobilization on Cu/Fe2O4 NPs is desirable for efficient enzyme loading and high relative activity, with remarkable bisphenol A degradation potential.

Automated summary

In this study, laccase was immobilized on Cu and Cu-magnetic nanoparticles to improve enzyme stability and potential applications. The immobilized laccase showed higher optimum pH and temperature, improved pH and temperature profiles, and enhanced thermal stability compared to the free enzyme. The Cu/Fe2O4-laccase also exhibited higher bisphenol A degradation potential.