On the use of a high-redox potential laccase as an alternative for the transformation of non-steroidal anti-inflammatory drugs (NSAIDs)

• Published in: Journal of molecular catalysis. B, Enzymatic Vol. 97; pp. 233 - 242
• Main Authors: Lloret, L., Eibes, G., Moreira, M.T., Feijoo, G., Lema, J.M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.12.2013; Elsevier
• Subjects: adverse effects; animals; Bioconversions. Hemisynthesis; biodegradability; Biological and medical sciences; Biotechnology; biotransformation; catalytic activity; cytotoxicity; Diclofenac; Fundamental and applied biological sciences. Psychology; gas chromatography-mass spectrometry; kidneys; Laccase; liver; Mediator; Methods. Procedures. Technologies; Naproxen; nonsteroidal anti-inflammatory agents; Transformation products; yields; Transformation products; Mediator; Naproxen; Laccase; Diclofenac; Drug; Enzyme; Antiinflammatory agent; Oxidoreductases; Redox potential
• ISSN: 1381-1177; 1873-3158
• DOI: 10.1016/j.molcatb.2013.08.021

•This work lays the foundation for enzymatic technology development to remove NSAIDs.•Enzyme mediators and pH effects were investigated and kinetics were evaluated.•Promising removal efficiencies of NPX and DCF and enzyme stability were found.•Identification of DCF biotransformation products and possible reaction pathways.•Laccase-catalyzed treatment improved biodegradability of the medium containing DCF. The release of pharmaceutical compounds to the environment, such as non-steroidal anti-inflammatory drugs (NSAIDs), implies a great concern because of its negative effects, e.g. potential cytotoxicity to liver and kidney of animal species. In the present study, a high-redox potential laccase is proposed as an alternative system for the biotransformation of selected NSAIDs: naproxen (NPX) and diclofenac (DCF). The effects of pH and the use of synthetic and natural mediators (1-hydroxybenzotriazole (HBT) and syringaldehyde (SA), respectively) were evaluated with the aim of optimizing the removal of NSAIDs by laccase. Results proved high removal yields for NPX (70–94%) after 24h in the presence of HBT at acidic and neutral pH, while DCF was completely transformed at pH 4 within shorter periods, from 30min to 4h, both in the absence or presence of mediators. The operation at a higher pH implied the addition of mediators to remove DCF, with values of 50 and 98% for SA and HBT, respectively. Kinetic parameters of the transformation reactions and laccase inactivation were estimated and compared for the different experimental conditions. Besides, the identification of the major biotransformation products of DCF was attempted: decarboxylated compounds were detected by gas chromatography-mass spectrometry and corresponding reaction pathways were proposed. Moreover, laccase-catalyzed treatment was demonstrated to significantly improve the aerobic biodegradability of the medium containing DCF in comparison with untreated solution, suggesting that DCF transformation products are less toxic than the parent compound.