Özet:

Objective: One of the sources of environment antibiotics contamination is wastewater treatment plants (WWTPs), there by constituting a global public health risk. This present study aimed to investigate the biodegradability of antibiotics and antiseptics and highlights the biodegradation of Ciprofloxacin as a sole carbon source by a bacterium isolated from the sludge "El Kouwaer," WWTP located in Mascara. Materials and Methods: In the present study, biodegradability of some antibiotics and antiseptic were tested at 50 mg/l concentration through active sludge microorganisms by Manometric Respirometry Method (OECD 301F). Further analysis of 16S rRNA gene sequencing used to identify MK4 strain isolated from the sludge. Furthermore, ATR-FTIR spectroscopy was conducted in order to identify its biodegradation in the presence of different carbon sources and LCMS/MS spectrometry were used to identify the metabolite degradation. Results: Our Results revealed that four antibiotics tested were readily biodegradable (60%) as Ciprofloxacin, Doxycycline, Amoxicillin, Ampicillin, and Penicillin. Conversely, other was not readily biodegradable, such as Azithromycin (36.11%), Cephalexin (36.20%), and Metronidazole (33.33%). Meanwhile, the remaining antibiotics under examination were degraded, with Sulfamethoxazole (25.75%), Clarithromycin (25.36%), and Nifuroxazide (16.33%) recording degradation. Ciprofloxacin was chosen to represent the most biodegraded antibiotic. Based on 16S rRNA gene, MK4 strain was related to Klebsiella oxytoca (99.99%). ATR-FTIR revealed that the strain K. oxytoca MK4 caused changes in the structure of the Ciprofloxacin, in the presence of various sources of carbon, with varying effects on bacterial growth and biodegradation. Conclusion: In this study, the identified strain K. oxytoca MK4 facilitated the degradation of Ciprofloxacin.

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