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- Biodegradation of 17α-Ethinylestradiol by strains of Aeromonas Genus isolated from acid mine drainagePublication . Da Luz Palma, Tânia Cristina; Costa, Maria Clara17α-ethinylestradiol (EE2), a synthetically derived analogue of endogenous estrogen, is widely employed as a hormonal contraceptive and is recognized as a highly hazardous emerging pollutant, causing acute and chronic toxic effects on both aquatic and terrestrial organisms. It has been included in the initial Water Watch List. The aim of this study was to isolate bacteria from consortia recovered from mine sediments and acid mine drainage samples, both considered extreme environments, with the ability to degrade EE2. From the most promising consortia, isolates affiliated with the Aeromonas, Rhizobium, and Paraburkholderia genera were obtained, demonstrating the capability of growing at 50 mg/L EE2. Subsequently, these isolates were tested with 9 mg/L of EE2 as the sole carbon source. Among the isolated strains, Aeromonas salmonicida MLN-TP7 exhibited the best performance, efficiently degrading EE2 (95 ± 8%) and reaching concentrations of this compound below the limits of detection within 7 and 9 days. The final metabolites obtained are in accordance with those of the TCA cycle; this may indicate EE2 mineralization. As far as is known, Aeromonas salmonicida was isolated for the first time and identified in acid mine drainage, demonstrating its capacity to degrade EE2, making it a promising candidate for bioaugmentation and suggesting its possible applicability in low pH environments.
- Putative role of flavobacterium, dokdonella and methylophilus strains in paracetamol biodegradationPublication . Da Luz Palma, Tânia Cristina; Mbagag NEBA, Donaldben; Costa, Maria Clara; Carlier, JorgeParacetamol, the most widely and globally used analgesic and antipyretic, is easily accumulated in aquatic environments. In the present study, the biodegradation of paracetamol in different media (one for general growth, one specific for sulfate reducing bacteria, a mineral salts medium and municipal wastewater) inoculated with two types of sludge (from anaerobic lagoon and from oxidation ditch) under different oxygenic conditions (anoxic; moderate oxygenation in open flasks and high oxygenation by aeration) was investigated. In addition, bacteria with relative abundances increasing simultaneously with paracetamol degradation, when this drug was the only carbon source, thus with a putative role in its degradation, were identified using 16S rRNA gene sequences. The results show that aerobic microorganisms had a major role in the degradation of paracetamol, with 50 mg/L totally removed from municipal wastewater after 2 days incubation with aeration, and that the metabolites 4-aminophenol and hydroquinone plus one compound not identified in this work were produced in the process. The identification of bacteria with a role in the degradation of paracetamol revealed a strain from genus Pseudomonas with the highest final relative abundance of 21.2%, confirming previous works reporting strains of this genus as paracetamol decomposers. Besides, genera Flavobacterium, Dokdonella and Methylophilus were also in evidence, with initial relative abundances of 1.66%, 1.48 and 0.00% (not detected) in the inoculum and 6.91%, 3.80 and 3.83% after incubation, respectively. Therefore, a putative role of these genera in paracetamol biodegradation is suggested for the first time.
- Biodegradation of paracetamol by some gram-positive bacterial isolatesPublication . Da Luz Palma, Tânia Cristina; Magno, Gustavo; Costa, Maria ClaraBacterial isolates with the capacity to remove paracetamol were selected from an activated sludge sample collected in an oxidation ditch of a wastewater treatment plant. Among these, twelve bacterial isolates were selected according to their capacity to grow in the presence of paracetamol. They were identified using the colony morphotype procedure and by 16S rRNA gene sequencing analysis, but only four of them showed the ability to utilise paracetamol as the sole carbon source in the presence of a nitrogen supply. Those four bacterial isolates were assigned to species of the genera Bacillus, [Brevibacterium], Corynebacterium and Enterococcus. Bacterial isolates were cultured in liquid mineral salt medium (MSM) spiked with 200 mg/L of paracetamol at 28 °C in the dark. In cultures inoculated with [Brevibacterium] frigoritolerans, Corynebacterium nuruki and Enterococcus faecium, removal of 97 ± 4%, 97 ± 6% and 86.9 ± 0.8% of paracetamol at 200 mg/L were obtained, respectively, while in the presence of a species belonging to Bacillus cereus group removal of the drug below the limits of detection was attained with evidence of mineralisation, after 144 h of incubation. During the degradation process, the metabolites 4-aminophenol, hydroquinone and 2-hexenoic acid were detected. As far as we know, these species are herein first-time described as paracetamol degraders.
- An autochthonous aerobic bacterial community and its cultivable isolates capable of degrading fluoxetinePublication . Palma, Tânia Cristina da Luz; Shylova, Anastasiia; Carlier, Jorge; Costa, Maria ClaraBACKGROUND 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.
- Photodegradation of chloramphenicol and paracetamol using PbS/TiO2 nanocomposites produced by green synthesisPublication . Palma, Tânia Cristina da Luz; Vieira, Bernardete; Nunes, J.; Lourenço, J. P.; Monteiro, O. C.; Costa, Maria ClaraThe present study describes the photocatalytic potential of the successfully synthesized nanocrystalline PbS/TiO2 nanocomposites in the photodegradation of chloramphenicol and paracetamol. PbS and PbS/TiO2 nanoparticles were synthesized using biological sulphide produced by sulphate-reducing bacteria in batch and in a coupled bioremediation system (upflow anaerobic packed-bed reactor) for acid mine drainage treatment, yielding near-complete metal precipitation (~ 100–99%, respectively). The PbS and PbS/TiO2 composites obtained using sulphide generated in batch have an average particle size ranging from 17 to 25 nm and 15 to 20 nm, respectively, while in bioreactor, both PbS and PbS/TiO2 particles have a similar size range from 20 to 50 nm. All the produced particles presented crystalline cubic structure. The specific surface area of TiO2 and PbS/TiO2 was estimated to be 46.559 m2/g and 38.005 m2/g, respectively. Chloramphenicol removal by photolysis was about 61% after 60 min of Hg irradiation and 36% under sunlight exposition. Chloramphenicol photodegradation using PbS/TiO2 as catalyst was successfully performed in a photoreactor (Hg medium pressure, 450 W) and under solar exposition with a high drug removal efficiency of 96% and 93% after 60 min and 240 min irradiation, respectively. Using TiO2 as a catalyst for photodegradation achieved 98% removal for both Hg and sunlight irradiation (UV index ranging 7–8) after 60 min and 240 min, respectively. Paracetamol removal by photolysis was about 18%. Drug’s photocatalytic degradation using PbS/TiO2 was successfully performed under sunlight exposition with a high removal efficiency of 93%, while in the presence of TiO2, the removal was complete, after 235 min irradiation.
- Anaerobic biodegradation of fluoxetine using a high-performance bacterial communityPublication . Da Luz Palma, Tânia Cristina; Costa, Maria ClaraFluoxetine (FLX), an antidepressant extensively used worldwide is considered an emerging pollutant. The present work intends to investigate for the first time the capacity of a bacterial community containing sulphate-reducing bacteria (SRB) enriched from an anaerobic sludge to biodegrade and use FLX as sole carbon source, since current literature suggests that this drug is poorly biodegraded being mainly removed by adsorption to sediments, where it persists. FLX was biodegraded under sulphate reducing conditions until reaching its lowest and reliably detectable concentration, when 20 mg/L of the drug was used as sole carbon source, while 66 ± 9% of 50 mg/L FLX was removed, after 31 days. The initial bacterial population was mainly constituted by Desulfomicrobium and Desulfovibrio whereas during the experiments using FLX as unique carbon source a clear shift occurred with the increase of vadinBC27 wastewater-sludge group, Macellibacteroidetes, Dethiosulfovibrio, Bacteroides, Tolumonas, Sulfuricurvum, f_Enterobacteriaceae_OTU_18 that are assumed for the first time as FLX degrading bacteria. Although the main mechanism of FLX removal described in literature is by adsorption, in the results herein presented anaerobic biodegradation appears to play the main role in the removal of the FLX, thus demonstrating the potentialities that the anaerobic processes can play in wastewater treatment aiming the removal of new emerging compounds.
- Batch studies on the biodegradation potential of Paracetamol, Fluoxetine and 17α-Ethinylestradiol by the Micrococcus yunnanensis Strain TJPT4 recovered from marine organismsPublication . Da Luz Palma, Tânia Cristina; Valentine, Julia; Gomes, Vera; Faleiro, L; Costa, MariaThe emerging pollutants paracetamol, fluoxetine and ethinylestradiol are inefficiently removed by conventional wastewater treatments, entering in aquatic environments in which they are hazardous. Aiming for the obtention of bacteria with the capacity for environmental bioremediation, eight bacteria were isolated from two consortia recovered from Hymedesmia versicolor and Filograna implexa marine organisms which exhibited a high-paracetamol-removal capacity. The isolates that displayed the ability to grow in the presence of 100 mg/L paracetamol as the sole carbon source were assigned to Paenibacillus, Micrococcus and Microbacterium genera. The isolate assigned to the Micrococcus yunnanensis strain TJPT4 presented the best performance, degrading 93 ± 4% of 15 mg/L paracetamol as the sole carbon source after 360 h, and was also apparently able to degrade the produced metabolites. This strain was able to remove 82.1 ± 0.9% of 16 mg/L fluoxetine after 504 h, mainly by adsorption, but apparently a biodegradation contribution also occurred. This strain was able to remove 66.6 ± 0.2% of 13 mg/L 17α-ethinylestradiol after 360 h. As far as is known, Micrococcus yunnanensis is for the first time recovered/identified in Filograna implexa, presenting a high drug removal efficiency, thereby becoming a great candidate for treatment processes (e.g., bioaugmentation), especially in the presence of saline intrusions.