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Advisor(s)
Abstract(s)
Fluoroquinolones constitute a group of emerging pollutants and their occurrence in different environmental
compartments is becoming object of increasing public concern due to their ecotoxicological effects
and the potential to develop resistant bacteria. This study aimed to investigate the biodegradation
of moxifloxacin (MOX), for which studies in the literature are very scarce. An activated sludge (AS)
consortium and three bacterial strains able to degrade fluoroaromatic compounds e strains F11, FP1 and
S2 e were tested. Biodegradation studies were conducted using acetate as a bulk carbon source. Strain
F11 showed the highest biodegradation capacity, being able to completely consume and dehalogenate
7.5 mM of the target antibiotic when daily co-supplemented with acetate present as a readily degradable
organic substrate in wastewaters. MOX could be used by strain F11 as a sole nitrogen source but the
presence of an external nitrogen source in the culture medium was essential for complete biodegradation.
Strain F11 was capable of completely consuming MOX in a range between 2 and 11 mM, although
stoichiometric fluoride release was not obtained for the highest tested concentration. The antibacterial
activity of residual MOX and of the metabolic products potentially resultant from the biodegradation
process was investigated by agar diffusion tests, demonstrating that MOX biodegradation is associated
with the elimination of the antibacterial properties of the target antibiotic and of the produced metabolites,
which is an important result, as the activity of antibiotics and/or their metabolites in the
environment, even at low levels, may lead to the development of resistant bacterial strains. Overall, the
results obtained in this study suggest that strain F11 is a promising microorganism for the treatment of
waters contaminated with MOX, where it could be used for bioaugmentation/bioremediation purposes.
To the best of our knowledge, this is the first study reporting complete removal and dehalogenation of
MOX by a single microorganism.
Description
Keywords
Moxifloxacin Fluoroquinolones Biodegradation Acetate Antimicrobial activity
Citation
CARVALHO, M. F.; MAIA, A. S.; TIRITAN, M. E.; CASTRO, P. M. L. - Bacterial degradation of moxifloxacin in the presence of acetate as a bulk substrate. Journal of Environmental Management. ISSN 0301-4797. Vol. 168 (2016), p. 219-228
Publisher
Academic Press