Biotransformation of the Fluoroquinolone, Levofloxacin, by the White-Rot Fungus Coriolopsis gallica

The wastewater from hospitals, pharmaceutical industries and more generally human and animal dejections leads to environmental releases of antibiotics that cause severe problems for all living organisms. The aim of this study was to investigate the capacity of three fungal strains to biotransform the fluoroquinolone levofloxacin. The degradation processes were analyzed in solid and liquid media. Among the three fungal strains tested, Coriolopsis gallica strain CLBE55 (BRFM 3473) showed the highest removal efficiency, with a 15% decrease in antibiogram zone of inhibition for Escherichia coli cultured in solid medium and 25% degradation of the antibiotic in liquid medium based on high-performance liquid chromatography (HPLC). Proteomic analysis suggested that laccases and dye-decolorizing peroxidases such as extracellular enzymes could be involved in levofloxacin degradation, with a putative major role for laccases. Degradation products were proposed based on mass spectrometry analysis, and annotation suggested that the main product of biotransformation of levofloxacin by Coriolopsis gallica is an N-oxidized derivative.

Automated summary

The wastewater containing antibiotics from hospitals, pharmaceutical industries, and human and animal excretion poses a significant threat to the environment. This study investigated the ability of three fungal strains to degrade the fluoroquinolone antibiotic levofloxacin. The results showed that Coriolopsis gallica strain CLBE55 exhibited the highest removal efficiency, with a 15% decrease in antibiogram zone of inhibition for Escherichia coli in solid medium and a 25% degradation of the antibiotic in liquid medium. Proteomic analysis suggested the involvement of laccases and dye-decolorizing peroxidases in the degradation process, with laccases playing a major role. Mass spectrometry analysis confirmed the formation of an N-oxidized derivative as the main product of levofloxacin biotransformation by Coriolopsis gallica.