Hierarchically-Structured Laccase@Ni3(Po4)2 Hybrid Nanoflowers for Antibiotic Degradation: Application in Real Wastewater Effluent and Toxicity Evaluation Publisher Pubmed



Jafarinodoushan H^{1, 2} ; Fazeli MR¹ ; Faramarzi MA² ; Samadi N^{1, 3}
Source: International Journal of Biological Macromolecules Published:2023

Abstract

Laccase@Ni3(PO4)2 hybrid nanoflowers (HNFs) were prepared by the anisotropic growth of biomineralized nickel phosphate. The immobilization yield was 77.5 ± 3.6 %, and the immobilized enzyme retained 50 % of its initial activity after 18 reusability cycles. The immobilized and free enzymes lost 80 % of their activity after 18 and 6 h incubation in municipal wastewater effluent (MWWE), respectively. The increase in α-helix content (8 %) following immobilization led to a more rigid enzyme structure, potentially contributing to its improved stability. The removal of ciprofloxacin from MWWE by laccase@Ni3(PO4)2·HNFs/p-coumaric acid oxidation system was optimized using a Box-Behnken design. Under the optimized conditions [initial laccase activity (0.05 U mL−1), the concentration of p-coumaric acid (2.9 mM), and treatment time (4.9 h)], the biocatalyst removed 90 % of ciprofloxacin (10 mg L−1) from MWWE. The toxicity of ciprofloxacin against some G+ and G− bacteria was reduced by 35–70 %, depending on their strain. The EC50 of ciprofloxacin for the alga Raphidocelis subcapitata reduced from 3.08 to 1.07 mg L−1 (p-value <0.05) after the bioremoval. Also, the acute and chronic toxicity of identified biodegradation products was lower than ciprofloxacin at three trophic levels, as predicted by ECOSAR software. © 2023 Elsevier B.V.