An autochthonous aerobic bacterial community and its cultivable isolates capable of degrading fluoxetine

BACKGROUND Fluoxetine is an antidepressant and recalcitrant fluorine pharmaceutical that is poorly biodegraded, so it enters the hydric resources and causes hazardous effects to aquatic environments. According to these fluoxetine features, the main aim of the present research was to find resistant bacteria in environmental samples with a high degradation efficiency. RESULTS The results obtained from raw municipal wastewater spiked with fluoxetine and inoculated with aerobic sludge from a Portuguese wastewater treatment plant under highly aerobic conditions showed that more than half and approximate to 89% of the drug was degraded after 48 and 144 h, respectively. During the assay, the initial population (mainly composed of Arcobacter, Bacteroides, and Macellibacteroides) shifted with an increase of members of the Acinetobacter, Rheinheimera, Shewanella, Pseudomonas, Methylobacillus, Piscinobacter genera and Aeromonadales order and the Pseudomonadaceae family, all of which were likely responsible for fluoxetine biodegradation. From the same sludge, six bacterial isolates were selected and identified as follows: Pseudomonas putida, Enterobacter ludwigii, Pseudomonas nitritireducens, Alcaligenes faecalis, Pseudomonas aeruginosa, and Pseudomonas nitroreducens; all of them grew with fluoxetine as sole carbon source. Pseudomonas nitroreducens showed the highest removal of 55 +/- 1% at 20 mg L-1 fluoxetine after 24 h. CONCLUSION An autochthonous aerobic bacterial community and its cultivable isolates showed the capacity to biodegrade fluoxetine. Biodegradation, rather than adsorption, appears to play the main role in the fluoxetine removal in aerobic conditions using bacteria simply obtained from an environmental sample. As far as is known, those bacteria are reported for the first time as fluoxetine biodegraders; thus, these bacteria are a promising option to integrate into new bioremediation processes aiming at the removal of fluoxetine. (c) 2021 Society of Chemical Industry (SCI).