Copper ions binding regulation for the high-efficiency biodegradation of ciprofloxacin and tetracycline-HCl by low-cost permeabilized-cells

Cu2+ plays a decisive role for the bio-oxidation in the active center of laccase. In the fermentation-purified process, the loss of Cu2+ reduces the activity and the high cost limits the application of laccase. In this study, a fermentation-permeabilization combined process were developed which based on the regulation of Cu2+ binding time to produce the permeabilized-cells containing laccase, in which Cu2+ can enter the cells freely to greatly improve the laccase activity and reduce the immobilization cost by about 19 times. So, the permeabilizedcells is suitable for biodegradation of antibiotic pollution in the environment, which was applied for the biodegradation of ciprofloxacin (CIP) and tetracycline-HCl (TCH) and the degradation efficiency reached 95.42% and 98.73%, respectively, with low ecotoxicity of the degradation products. Finally, the degradation mechanism was analyzed theoretically by molecular docking. Therefore, this study provided a low-cost, eco-friendly, and widely applicable method for organic pollutants removal.

Automated summary

This study developed a fermentation-permeabilization combined process to increase laccase activity by regulating Cu2+ binding time, which was applied for biodegradation of antibiotic pollution with high degradation efficiency and low ecotoxicity.