Immobilization of Pleurotus eryngii Laccase via a Protein-Inorganic Hybrid for Efficient Degradation of Bisphenol A as a Potent Xenobiotic.

Abstract

In the present investigation, an eco-friendly biocatalyst was developed using Pleurotus eryngii laccase (PeLac) through a copper (Cu)-based protein-inorganic hybrid system for the degradation of bisphenol A, a representative xenobiotic. After partial purification, the specific activity of crude PeLac was 92.6 U/mg of total protein. Immobilization of PeLac as Cu₃(PO₄)₂-Lac (Cu-PeLac) nanoflowers (NFs) at 4 °C resulted in a relative activity 333% higher than that of the free enzyme. The Cu-PeLac NFs exhibited greater pH and temperature stability and enhanced catalytic activity compared to free laccase. This enhanced activity was validated through improved electrochemical properties. After immobilization, Cu-PeLac NFs retained up to 8.7-fold higher residual activity after storage at 4 °C for 30 days. Free and immobilized laccase degraded bisphenol A by 41.6% and 99.8%, respectively, after 2 h of incubation at 30 °C. After ten cycles, Cu-PeLac NFs retained 91.2% degradation efficiency. In the presence of potent laccase inhibitors, Cu-PeLac NFs exhibited a 47.3-fold improvement in bisphenol A degradation compared to free PeLac. Additionally, the synthesized Cu-PeLac NFs demonstrated lower acute toxicity against Vibrio fischeri than Cu nanoparticles. This study presents the first report of PeLac immobilization through an eco-friendly protein-inorganic hybrid system, with promising potential for degrading bisphenol A in the presence of inhibitors to support sustainable development.