Browsing by Author "Costa, Maria Clara"
Now showing 1 - 10 of 48
Results Per Page
Sort Options
- A bridge between liquid-liquid extraction and the use of bacterial communities for palladium and platinum recovery as nanosized metal sulphidesPublication . Assunção, Ana; Matos, Ana; Costa, Ana M. Rosa da; Candeias, Antonio; Costa, Maria ClaraThe Platinum Group Metals (PGM) are rare in the Earth's crust and in the past years their use had a considerable expansion limiting their availability, which justifies PGM's high commercial value and demand. Therefore, PGM recovery from secondary sources is very important from both economic and environmental points of view. In recent years, several methods for PGM removal have been investigated. Our research group has been studying the removal/recovery of PGM using both chemical (liquid liquid extraction) and biological methods (using anaerobic bacterial communities).The aim of this study was to combine these two chemical and biological approach technologies, for PGM recovery. For that purpose, Pd(II) and Pt(IV) present in aqueous phases, were extracted to organic phases composed by N,N'-dimethyl-N,N'-dicyclohexylsuccinamide (DMDCHSA) and N,N'-dimethyl-N,N'-dicyclohexyltetradecylmalonamide (DMDCHTDMA) in 1,2-dichloroethane, respectively, with an extraction efficiency of 79% for Pd(II) and 99% for Pt(IV). The metals in the loaded organic phases were then stripped with seawater, a low-cost solution largely available in nature, with efficiencies of 100% for Pd and 86% for Pt. Finally, the metals were precipitated and recovered using metabolic products produced by a community enriched for sulphate-reducing bacteria. The palladium precipitated completely, while 86% of platinum was precipitated. During the precipitation process sulphide concentration in the solution decreased and the analysis of the precipitates was consistent with the formation of nanosized PdS and PtS2.To our knowledge, this research shows, for the first time, the potential of combining liquid liquid extraction with the use of bacteria aiming platinum and palladium recovery, as metal sulphides, from aqueous media. (C) 2016 Elsevier B.V. All rights reserved.
- A review of plant metabolites with metal interaction capacity: a green approach for industrial applicationsPublication . Nobahar, Amir; Carlier, Jorge Dias; Miguel, Maria Graca; Costa, Maria ClaraRapid industrial development is responsible for severe problems related to environmental pollution. Many human and industrial activities require different metals and, as a result, great amounts of metals/heavy metals are discharged into the water and soil making them dangerous for both human and ecosystems and this is being aggravated by intensive demand and utilization. In addition, compounds with metal binding capacities are needed to be used for several purposes including in activities related to the removal and/or recovery of metals from effluents and soils, as metals' corrosion inhibitors, in the synthesis of metallic nanoparticles and as metal related pharmaceuticals, preferably a with minimum risks associated to the environment. Plants are able to synthesize an uncountable number of compounds with numerous functions, including compounds with metal binding capabilities. In fact, some of the plants' secondary metabolites can bind to various metals through different mechanisms, as such they are excellent sources of such compounds due to their high availability and vast diversity. In addition, the use of plant-based compounds is desirable from an environmental and economical point of view, thus being potential candidates for utilization in different industrial activities, replacing conventional physiochemical methods. This review focuses on the ability of some classes of compounds that can be found in relatively high concentrations in plants, having good metal binding capacities and thus with potential utilization in metal based industrial activities and that can be involved in the progressive development of new environmentally friendly strategies.
- Acid mine drainage bioremediation using bacteria enriched from the confluence zone between its flow and treated sewagePublication . Nobahar, Amir; Fitas, Eduardo Trindadde; Costa, Maria Clara; Carlier, JorgeSediments from the confuence zone between an acid mine drainage stream and a water stream receiving the efuent from a municipal wastewater treatment plant were inoculated in a Postgate B medium base having methanol, glycerol, or etha[1]nol as carbon source/electron donor, over a pH range between 2.00 and 6.00, aiming to obtain native cultures enriched in acidophilic/acid-tolerant sulfate-reducing bacteria. The most efective sulfate reduction observed in acidic conditions was in the enrichment cultures with methanol. Thus, the microbial consortium enriched in these conditions was further used in acid mine drainage bioremediation experiments at an initial pH of 4.50 and using diferent doses of nutrients medium base and methanol as carbon source/electron donor. The most promising results, with more than 99% removal of metals, were obtained in the mixture of 20% Postgate B medium base plus 80% acid mine drainage (v/v), which corresponds to 0.115% basal salts and 0.02% yeast extract (w/v). Metataxonomic analysis based on 16S rRNA gene sequences showed the presence of Desulfosporosinus spp. in all enrichment cultures, with the highest relative abundance in cultures at pH 4.00 with methanol. Furthermore, metataxonomic analysis in the acid mine drainage remediation tests revealed the presence of Desulfosporosi[1]nus spp. in all tested conditions. In addition, the study also revealed Clostridium members in all tests. Plus, their relative abundances were related to the dose of nutrient medium base and in balance with the abundances of Desulfosporosinus spp.
- 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.
- 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.
- Antioxidant activity and enzyme inhibitory potential of Euphorbia resinifera and E. officinarum honeys from Morocco and plant aqueous extractsPublication . Boutoub, Oumaima; EL-Geundouz, Soukaina; Estevinho, Leticia M.; Paula, Vanessa B.; Aazza, Smail; El Ghadraoui, Lahsen; Rodrigues, Brígida; Raposo, Sara; Carlier, Jorge; Costa, Maria Clara; Miguel, MariaNatural products may be applied in a wide range of domains, from agriculture to food and pharmaceutical industries. In this study, the antioxidant properties and the capacity to inhibit some enzymatic activities ofEuphorbia resiniferaandEuphorbia officinarumaqueous extracts and honeys were assessed. The physicochemical characteristics were also evaluated. Higher amounts of iron, copper and aluminium were detected inE. officinarumhoney, which may indicate environmental pollution around the beehives or inadequate storage of honey samples. This honey sample showed higher amounts of total phenols and better capacity for scavenging superoxide anion free radicals and DPPH free radicals as compared withE. resiniferahoney, but poorer capacity for inhibiting lipoxygenase, acetylcholinesterase, tyrosinase and xanthine oxidase. The ratio plant mass:solvent volume (1:100) and extraction time (1 - 2 h) were associated with higher total phenols and better antioxidant activities and lipoxygenase, acetylcholinesterase and tyrosinase inhibitory activities, regardless of the plant species. The aqueous extracts had systematically higher in vitro activities than the respective honey samples.
- Application of urea-agarose gel electrophoresis to select non-redundant 16S rRNAs for taxonomic studies: palladium(II) removal bacteriaPublication . Assunção, Ana; Costa, Maria Clara; Carlier, JorgeThe 16S ribosomal RNA (rRNA) gene has been the most commonly used sequence to characterize bacterial communities. The classical approach to obtain gene sequences to study bacterial diversity implies cloning amplicons, selecting clones, and Sanger sequencing cloned fragments. A more recent approach is direct sequencing of millions of genes using massive parallel technologies, allowing a large-scale biodiversity analysis of many samples simultaneously. However, currently, this technique is still expensive when applied to few samples; therefore, the classical approach is still used. Recently, we found a community able to remove 50 mg/L Pd(II). In this work, aiming to identify the bacteria potentially involved in Pd(II) removal, the separation of urea/heat-denatured DNA fragments by urea-agarose gel electrophoresis was applied for the first time to select 16S rRNA-cloned amplicons for taxonomic studies. The major raise in the percentage of bacteria belonging to genus Clostridium sensu stricto from undetected to 21 and 41 %, respectively, for cultures without, with 5 and 50 mg/L Pd(II) accompanying Pd(II) removal point to this taxa as a potential key agent for the bio-recovery of this metal. Despite sulfate-reducing bacteria were not detected, the hypothesis of Pd(II) removal by activity of these bacteria cannot be ruled out because a slight decrease of sulfate concentration of the medium was verified and the formation of PbS precipitates seems to occur. This work also contributes with knowledge about suitable partial 16S rRNA gene regions for taxonomic studies and shows that unidirectional sequencing is enough when Sanger sequencing cloned 16S rRNA genes for taxonomic studies to genus level.
- A bacterial consortium isolated from an Icelandic fumarole displays exceptionally high levels of sulfate reduction and metals resistancePublication . Alexandrino, Maria; Macías, Francisco; Da Silva Costa, Rodrigo; Gomes, Newton C. M.; Canario, Adelino V. M.; Costa, Maria ClaraThe soils of three fumaroles and one mining site, all with high metal content, were surveyed for the presence of metal-resistant sulfate-reducing bacteria and their potential application in the bioremediation of acid mine drainages. By means of selective soil enrichments a bacterial consortium was isolated from an Icelandic fumarole that displayed very high sulfate reduction in the presence of a mixture of 0.75 g/L of Fe, 0.20 g/L of Zn and 0.080 g/L of Cu. Under these conditions the bacterial consortium reduced 91% of the added 3.9 g/L of sulfate after 28 days, precipitating 100% of the Fe, 96% of the Zn and 97% of the Cu during the same time. Both total bacterial numbers and numbers of culturable sulfate-reducing bacteria remained unchanged when grown in media containing metals, suggesting low or absent inhibitory effects of the metals on the bacterial consortium. PCR-DGGE profiles of the sulfate reducing bacterial communities obtained from the Icelandic fumarole sample showed that bacterial diversity decreased significantly after metal addition: from the original 12 ribotypes only two were detected in the metaltolerant culture. Phylogenetic analysis of 16S ribosomal RNA gene sequences revealed that these two ribotypes were affiliated with the genera Clostridium and Desulfovibrio, with C. subterminale, C. pascui, C. mesophilum and C. peptidovorans and D. desulfuricans identified as their closest relatives.
- Batch studies on the biodegradation of paracetamol and 1,4-hydroquinone by novel bacterial strains isolated from extreme environmental samples and the identification of candidate catabolic genesPublication . Lara-Moreno, Alba; Fatma El-Sayed; Cox, Cymon; Costa, Maria Clara; Carlier, JorgeThe emerging pollutant paracetamol (APAP) is one of the most prescribed drugs worldwide. In addition, APAP and its main metabolites, namely, 4-aminophenol (4-AP), hydroquinone (H2Q), benzoquinone (BQ), and 2,5-dihydroxy-1,4-benzoquinone (2,5-OH-BQ), among others, are frequently detected in wastewater treatment plants (WWTPs) influents, effluents, and the environment. Thus, continuous release into the environment, especially aquatic environments, is a source of general concern. Six APAP-degrading bacterial strains were isolated from two mine samples from the Iberian Pyrite Belt (Lousal and Poderosa mines). Mycolicibacterium aubagnense HPB1.1, which was isolated using enrichment cultures from the Poderosa mine sample in the presence of H2Q as the sole carbon source, also showed APAP biodegrading capabilities. Pure cultures of this strain degraded 34.3 mg L-1 of APAP in 5 days and 9.4 mg L-1 of H2Q in 4 days. Interestingly, BQ and 2,5-OH-BQ were detected as metabolites resulting from H2Q abiotic degradation, but these compounds were removed in the strain's cultures. Furthermore, M. aubagnense HPB1.1 whole-genome was sequenced, and its encoded proteins were aligned with enzymes of APAP-degrading bacteria recovered from databases and literature aiming to identify candidate catabolic genes. Putative amidases, deaminases, hydroxylases, and dioxygenases, responsible for the degradation of APAP by the HPB1.1 strain, were identified by similarity, corroborating its ability to transform APAP and its intermediate metabolite H2Q into less toxic metabolic compounds due to their capacity to break the aromatic ring of these molecules.
- 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.