Reversible immobilization of laccase onto metal-ion-chelated magnetic microspheres for bisphenol A removal

• In this study, laccase was reversibly immobilized on Cu(ΙΙ) and Mn(ΙΙ) chelated magnetic microspheres and successfully applied for the removal of bisphenol A (BPA) from water.
• The laccase adsorption capacities of the magnetic microspheres did not change after five successive adsorption–desorption cycles.
• The immobilized laccase exhibited high removal efficiency of BPA under the combined actions of biodegradation and adsorption.
• In comparison with free laccase, the thermal and storage stabilities of the immobilized laccase were significantly improved.

Increasing attention has been given to nanobiocatalysis for commercial applications. In this study, laccase was reversibly immobilized onto Cu(ΙΙ)- and Mn(ΙΙ)-chelated magnetic microspheres and successfully applied to remove bisphenol A (BPA) from water. The results indicated that the loading of laccase onto the metal-ion-chelated magnetic microspheres was approximately 100 mg/g. After five successive adsorption–desorption cycles, the laccase adsorption capacities did not change. In comparison with free laccase, the thermal and storage stabilities of immobilized laccase were significantly improved. Immobilized laccase exhibited a high removal efficiency for BPA under the combined actions of biodegradation and adsorption. Greater than 85% of BPA was removed under optimum conditions. The effects of various factors on the BPA removal efficiency of immobilized laccase were analysed. The results showed that metal-ion-chelated magnetic microspheres have great potential for industrial applications.