Biotransformation of Antibiotics by Coriolopsis gallica: Degradation of Compounds Does Not Always Eliminate Their Toxicity

Background/Objectives: Wastewaters containing antibiotics pose risks to human health and soil ecosystems. In this study, the white-rot fungus Coriolopsis gallica (a basidiomycete exhibiting high laccase production) was used for the biotransformation of three antibiotics (50 mg L−1): tetracycline, chloramphenicol, and sulfanilamide. Methods: The biotransformation process was investigated in liquid and solid media using high-performance liquid chromatography (HPLC) and the bacterial growth inhibition agar well diffusion method, respectively. Results: Among the three antibiotics tested, tetracycline showed the highest biotransformation efficiency, achieving a 100% removal rate in the liquid medium and a 100% decrease in the growth inhibition of Escherichia coli in the solid medium. Chloramphenicol and sulfanilamide were partially removed (20% and 16%, respectively) after 12 days of treatment in more than one step without the loss of their antibacterial activities. The presence of these antibiotics in the culture medium of C. gallica enhanced laccase activity, indicating that this ligninolytic enzyme might participate in the biotransformation process. Conclusions: Thus, the results reported in this article extend our knowledge of the catalytic potential of C. gallica and give further perspectives for its application in the biodegradation of antibiotics. To the best of our knowledge, this is the first study wherein C. gallica was used for the treatment of tetracycline, chloramphenicol, and sulfanilamide.