The proliferation and possible adverse effects of emerging contaminants such as pharmaceutical and personal care products (PPCPs) in waters and the environment is causing increased concern. We investigated the dissipation of three PPCPs: ibuprofen (IBP), diclofenac (DCF) and triclosan (TCS), separately or in mixture, in the ppm range in microcosm biopurification systems (BPS), paying special attention to their effect on bacterial ecotoxicity and on bacterial community structure and composition. The results reveal that the BPS efficiently dissipates IBP and DCF with 90% removal after 45 and 84 days of incubation, respectively. However, removal of TCS required longer incubation, 127 days for 90% removal. Furthermore, dissipation of the three PPCPs was slower when all three were applied to the BPS as a mixture. TCS had an initial negative effect on bacterial viability by a decrease of 34-43%; however, this effect was mitigated when all three PPCPs were present simultaneously. The bacterial communities in the BPS were affected much more by incubation time than by the applied PPCPs.Nonetheless, the PPCPs affected differentially the composition and relative abundance of bacterial taxa. IBP and DCF initially increased bacterial diversity and richness while exposure to TCS generally provoked the opposite effect. TCS had the largest effect on bacterial groups negatively affecting the relative abundance of Acidobacteria, Rickettsiales, Methylophilales, Methylacidiphilae and Phycisphaerae. On the other hand, all three PPCPs stimulated the dominant bacterial families Promicromonosporaceae, Caulobacteraceae, Xanthomonadaceae, Cyclobacteriaceae, Sphingobacteriaceae and Verrucomicrobiaceae, whose members could harbour mechanisms for resistance by degradation and/or detoxification.
Paracetamol is one of the most used pharmaceuticals worldwide, but due to its widespread use it is detected in various environmental matrices, such as surface and ground waters, sediments, soils or even plants, where it is introduced mainly from the discharge of wastewater and the use of sewage sludge as fertilizer in agriculture. Its accumulation in certain organisms can induce reproductive, neurotoxic or endocrine disorders, being therefore considered an emerging pollutant. This study reports on the isolation, from sewage sludge produced in wastewater treatment plants (WWTPs), of bacterial strains capable of degrading paracetamol. Up to 17 bacterial strains were isolated, but only two of them, identified as Pseudomonas stutzeri CSW02 and Pseudomonas extremaustralis CSW01, were able to degrade very high concentrations of paracetamol in solution as a sole carbon and energy source, and none of them had been previously described as paracetamol degraders. These bacteria showed the ability to degrade up to 500 mg L−1 of paracetamol in only 6 and 4 h, respectively, much quicker than any other paracetamol-degrader strain described in the literature. The two main paracetamol metabolites, 4-aminophenol and hydroquinone, which present high toxicity, were detected during the degradation process, although they disappeared very quickly for paracetamol concentrations up to 500 mg L−1. The IC50 of paracetamol for the growth of these two isolates was also calculated, indicating that P. extremaustralis CSW01 was more tolerant than S. stutzeri CSW02 to high concentrations of paracetamol and/or its metabolites in solution, and this is the reason for the much lower paracetamol degradation by S. stutzeri CSW02 at 2000–3000 mg L−1. These findings indicate that both bacteria are very promising candidates for their use in paracetamol bioremediation in water and sewage sludge.
Here, we report the genome sequences of one Achromobacter and four Pseudomonas strains isolated from sediments of the River Elbe which are highly tolerant toward the xenobiotic target compound diclofenac, a nonsteroidal anti-inflammatory drug (NSAID) and emerging contaminant.
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