Biodegradation of Diclofenac by the bacterial strain Labrys portucalensis F11

• Published in: Ecotoxicology and environmental safety Vol. 152; pp. 104 - 113
• Main Authors: Moreira, Irina S., Bessa, Vânia S., Murgolo, Sapia, Piccirillo, Clara, Mascolo, Giuseppe, Castro, Paula M.L.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 15.05.2018
• Subjects: Biodegradation; Co-metabolism; Diclofenac; Labrys portucalensis F11; Metabolites; Biodegradation; Co-metabolism; Metabolites; Diclofenac; Labrys portucalensis F11
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2018.01.040

Diclofenac (DCF) is a widely used non-steroidal anti-inflammatory pharmaceutical which is detected in the environment at concentrations which can pose a threat to living organisms. In this study, biodegradation of DCF was assessed using the bacterial strain Labrys portucalensis F11. Biotransformation of 70% of DCF (1.7–34 μM), supplied as the sole carbon source, was achieved in 30 days. Complete degradation was reached via co-metabolism with acetate, over a period of 6 days for 1.7 µM and 25 days for 34 μM of DCF. The detection and identification of biodegradation intermediates was performed by UPLC-QTOF/MS/MS. The chemical structure of 12 metabolites is proposed. DCF degradation by strain F11 proceeds mainly by hydroxylation reactions; the formation of benzoquinone imine species seems to be a central step in the degradation pathway. Moreover, this is the first report that identified conjugated metabolites, resulting from sulfation reactions of DCF by bacteria. Stoichiometric liberation of chlorine and no detection of metabolites at the end of the experiments are strong indications of complete degradation of DCF by strain F11. To the best of our knowledge this is the first report that points to complete degradation of DCF by a single bacterial strain isolated from the environment. [Display omitted] •Complete biodegradation of Diclofenac by L. portucalensis F11 was achieved;•Degradation in co-metabolism with acetate resulted in stoichiometric chloride release;•The kinetics and pathway of diclofenac degradation was proposed;•The supplementation with acetate resulted in increased biodegradation rate constants;•The chemical structure of twelve degradation intermediates is proposed.