151 results on '"Dehalococcoides mccartyi"'
Search Results
2. Enrichment of Aerobic and Anaerobic Hydrocarbon-Degrading Bacteria from Multicontaminated Marine Sediment in Mar Piccolo Site (Taranto, Italy).
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Matturro, Bruna, Di Franca, Maria Letizia, Tonanzi, Barbara, Cruz Viggi, Carolina, Aulenta, Federico, Di Leo, Magda, Giandomenico, Santina, and Rossetti, Simona
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MARINE sediments ,ANAEROBIC bacteria ,ANAEROBIC microorganisms ,POLYCYCLIC aromatic hydrocarbons ,NATURAL resources ,SEDIMENT sampling ,BACTERIAL adaptation - Abstract
Marine sediments act as a sink for the accumulation of various organic contaminants such as polychlorobiphenyls (PCBs). These contaminants affect the composition and activity of microbial communities, particularly favoring those capable of thriving from their biodegradation and biotransformation under favorable conditions. Hence, contaminated environments represent a valuable biological resource for the exploration and cultivation of microorganisms with bioremediation potential. In this study, we successfully cultivated microbial consortia with the capacity for PCB removal under both aerobic and anaerobic conditions. The source of these consortia was a multicontaminated marine sediment collected from the Mar Piccolo (Taranto, Italy), one of Europe's most heavily polluted sites. High-throughput sequencing was employed to investigate the dynamics of the bacterial community of the marine sediment sample, revealing distinct and divergent selection patterns depending on the imposed reductive or oxidative conditions. The aerobic incubation resulted in the rapid selection of bacteria specialized in oxidative pathways for hydrocarbon transformation, leading to the isolation of Marinobacter salinus and Rhodococcus cerastii species, also known for their involvement in aerobic polycyclic aromatic hydrocarbons (PAHs) transformation. On the other hand, anaerobic incubation facilitated the selection of dechlorinating species, including Dehalococcoides mccartyi, involved in PCB reduction. This study significantly contributes to our understanding of the diversity, dynamics, and adaptation of the bacterial community in the hydrocarbon-contaminated marine sediment from one sampling point of the Mar Piccolo basin, particularly in response to stressful conditions. Furthermore, the establishment of consortia with biodegradation and biotransformation capabilities represents a substantial advancement in addressing the challenge of restoring polluted sites, including marine sediments, thus contributing to expanding the toolkit for effective bioremediation strategies. [ABSTRACT FROM AUTHOR] more...
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- 2023
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3. Coupling of bioelectrochemical toluene oxidation and trichloroethene reductive dechlorination for single-stage treatment of groundwater containing multiple contaminants
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Carolina Cruz Viggi, Matteo Tucci, Marco Resitano, Simona Crognale, Maria Letizia Di Franca, Simona Rossetti, and Federico Aulenta
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Bioelectric well ,Dehalococcoides mccartyi ,Electrobioremediation ,Groundwater remediation ,Toluene ,Trichloroethene ,Environmental sciences ,GE1-350 ,Environmental technology. Sanitary engineering ,TD1-1066 - Abstract
Bioremediation of groundwater contaminated by a mixture of aromatic hydrocarbons and chlorinated solvents is typically challenged because these contaminants are degraded via distinctive oxidative and reductive pathways, thus requiring different amendments and redox conditions. Here, we provided the proof-of-concept of a single-stage treatment of synthetic groundwater containing toluene and trichloroethene (TCE) in a tubular bioelectrochemical reactor, known as a “bioelectric well”. Toluene was degraded by a microbial bioanode (up to 150 μmol L−1 d−1) with a polarized graphite anode (+0.2 V vs. SHE) serving as the terminal electron acceptor. The electric current deriving from microbially-driven toluene oxidation resulted in (abiotic) hydrogen production (at a stainless-steel cathode), which sustained the reductive dechlorination of TCE to less-chlorinated intermediates (i.e., cis-DCE, VC, and ETH), at a maximum rate of 500 μeq L−1 d−1, in the bulk of the reactor. A phylogenetic and functional gene-based analysis of the “bioelectric well” confirmed the establishment of a microbiome harboring the metabolic potential for anaerobic toluene oxidation and TCE reductive dechlorination. However, Toluene degradation and current generation were found to be rate-limited by external mass transport phenomena, thus indicating the existing potential for further process optimization. more...
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- 2022
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4. Corrigendum: Metagenomic Analysis Reveals Microbial Interactions at the Biocathode of a Bioelectrochemical System Capable of Simultaneous Trichloroethylene and Cr(VI) Reduction
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Bruna Matturro, Marco Zeppilli, Agnese Lai, Mauro Majone, and Simona Rossetti
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reductive dechlorination ,Cr(VI) reduction ,bioelectrochemical remediation ,Dehalococcoides mccartyi ,Methanobacterium formicicum ,Methanobrevibacter arboriphilus ,Microbiology ,QR1-502 - Published
- 2022
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5. Metagenomic Analysis Reveals Microbial Interactions at the Biocathode of a Bioelectrochemical System Capable of Simultaneous Trichloroethylene and Cr(VI) Reduction
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Bruna Matturro, Marco Zeppilli, Agnese Lai, Mauro Majone, and Simona Rossetti
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reductive dechlorination ,Cr(VI) reduction ,bioelectrochemical remediation ,Dehalococcoides mccartyi ,Methanobacterium formicicum ,Methanobrevibacter arboriphilus ,Microbiology ,QR1-502 - Abstract
Bioelectrochemical systems (BES) are attractive and versatile options for the bioremediation of organic or inorganic pollutants, including trichloroethylene (TCE) and Cr(VI), often found as co-contaminants in the environment. The elucidation of the microbial players’ role in the bioelectroremediation processes for treating multicontaminated groundwater is still a research need that attracts scientific interest. In this study, 16S rRNA gene amplicon sequencing and whole shotgun metagenomics revealed the leading microbial players and the primary metabolic interactions occurring in the biofilm growing at the biocathode where TCE reductive dechlorination (RD), hydrogenotrophic methanogenesis, and Cr(VI) reduction occurred. The presence of Cr(VI) did not negatively affect the TCE degradation, as evidenced by the RD rates estimated during the reactor operation with TCE (111±2 μeq/Ld) and TCE/Cr(VI) (146±2 μeq/Ld). Accordingly, Dehalococcoides mccartyi, the primary biomarker of the RD process, was found on the biocathode treating both TCE (7.82E+04±2.9E+04 16S rRNA gene copies g−1 graphite) and TCE/Cr(VI) (3.2E+07±2.37E+0716S rRNA gene copies g−1 graphite) contamination. The metagenomic analysis revealed a selected microbial consortium on the TCE/Cr(VI) biocathode. D. mccartyi was the sole dechlorinating microbe with H2 uptake as the only electron supply mechanism, suggesting that electroactivity is not a property of this microorganism. Methanobrevibacter arboriphilus and Methanobacterium formicicum also colonized the biocathode as H2 consumers for the CH4 production and cofactor suppliers for D. mccartyi cobalamin biosynthesis. Interestingly, M. formicicum also harbors gene complexes involved in the Cr(VI) reduction through extracellular and intracellular mechanisms. more...
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- 2021
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6. Metagenomic Analysis Reveals Microbial Interactions at the Biocathode of a Bioelectrochemical System Capable of Simultaneous Trichloroethylene and Cr(VI) Reduction.
- Author
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Matturro, Bruna, Zepilli, Marco, Lai, Agnese, Majone, Mauro, and Rossetti, Simona
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METAGENOMICS ,BIOMARKERS ,TRICHLOROETHYLENE ,SHOTGUN sequencing ,METHANOBACTERIUM ,BIOSYNTHESIS - Abstract
Bioelectrochemical systems (BES) are attractive and versatile options for the bioremediation of organic or inorganic pollutants, including trichloroethylene (TCE) and Cr(VI), often found as co-contaminants in the environment. The elucidation of the microbial players' role in the bioelectroremediation processes for treating multicontaminated groundwater is still a research need that attracts scientific interest. In this study, 16S rRNA gene amplicon sequencing and whole shotgun metagenomics revealed the leading microbial players and the primary metabolic interactions occurring in the biofilm growing at the biocathode where TCE reductive dechlorination (RD), hydrogenotrophic methanogenesis, and Cr(VI) reduction occurred. The presence of Cr(VI) did not negatively affect the TCE degradation, as evidenced by the RD rates estimated during the reactor operation with TCE (111±2 μeq/Ld) and TCE/Cr(VI) (146±2 μeq/Ld). Accordingly, Dehalococcoides mccartyi , the primary biomarker of the RD process, was found on the biocathode treating both TCE (7.82E+04±2.9E+04 16S rRNA gene copies g
−1 graphite) and TCE/Cr(VI) (3.2E+07±2.37E+0716S rRNA gene copies g−1 graphite) contamination. The metagenomic analysis revealed a selected microbial consortium on the TCE/Cr(VI) biocathode. D. mccartyi was the sole dechlorinating microbe with H2 uptake as the only electron supply mechanism, suggesting that electroactivity is not a property of this microorganism. Methanobrevibacter arboriphilus and Methanobacterium formicicum also colonized the biocathode as H2 consumers for the CH4 production and cofactor suppliers for D. mccartyi cobalamin biosynthesis. Interestingly, M. formicicum also harbors gene complexes involved in the Cr(VI) reduction through extracellular and intracellular mechanisms. [ABSTRACT FROM AUTHOR] more...- Published
- 2021
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7. Correlations between maximum reductive dechlorination rates and specific biomass parameters in Dehalococcoides mccartyi consortia enriched on chloroethenes PCE, TCE and cis-1,2-DCE.
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Matturro, B, Majone, M, Aulenta, F, and Rossetti, S
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BIOMASS , *BACTERIAL population , *DEHALOGENASES , *BIOLOGICAL models , *RIBOSOMAL RNA - Abstract
One of the challenges to implementing the modeling of the biological reductive dechlorination (RD) process is the evaluation of biological parameters that represent the abundance/activity levels of the microorganisms involved in the biodegradation of chloroethenes. Here we report a combined analysis of kinetic and specific biomass parameters conducted on three dechlorinating consortia enriched on PCE, TCE and cis-1,2-DCE. In these consortia, Dehalococcoides mccartyi (Dhc) represented ≥70% of the bacterial population identified via 16S rRNA gene amplicon sequencing. Quantitative biomolecular methods were used to generate specific biomass parameters targeting either the Dhc population (16S rRNA genes or cells) or specific genes encoding RD process-involved reductive dehalogenases. The correlation factor between the abundance of active Dhc cells or tceA gene copies and maximum RD rates allowed to predict an increment of 7E+09 of active Dhc cells or 5E+09 tceA gene copies/L under controlled conditions. Diversely, the utilization of gene transcripts as biomass parameters for RD modeling did not provide reliable correlations with kinetic performances. This study provides valuable insights for further modeling of the RD process through the utilization of specific biomass parameters. [ABSTRACT FROM AUTHOR] more...
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- 2021
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8. Growth of Dehalococcoides spp. and increased abundance of reductive dehalogenase genes in anaerobic PCB-contaminated sediment microcosms.
- Author
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Ewald, Jessica M., Humes, Shelby V., Martinez, Andres, Schnoor, Jerald L., and Mattes, Timothy E.
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HAZARDOUS waste sites ,POLYCHLORINATED biphenyls ,SEDIMENTS ,ELECTRON donors ,CONTAMINATED sediments - Abstract
Polychlorinated biphenyls (PCBs) contaminate 19% of US Superfund sites and represent a serious risk to human and environmental health. One promising strategy to remediate PCB-contaminated sediments utilizes organohalide-respiring bacteria (OHRB) that dechlorinate PCBs. However, functional genes that act as biomarkers for PCB dechlorination processes (i.e., reductive dehalogenase genes) are poorly understood. Here, we developed anaerobic sediment microcosms that harbor an OHRB community dominated by the genus Dehalococcoides. During the 430-day microcosm incubation, Dehalococcoides 16S rRNA sequences increased two orders of magnitude to 10
7 copies/g of sediment, and at the same time, PCB118 decreased by as much as 70%. In addition, the OHRB community dechlorinated a range of penta- and tetra-chlorinated PCB congeners including PCBs 66, 70 + 74 + 76, 95, 90 + 101, and PCB110 without exogenous electron donor. We quantified candidate reductive dehalogenase (RDase) genes over a 430-day incubation period and found rd14, a reductive dehalogenase that belongs to Dehalococcoides mccartyi strain CG5, was enriched to 107 copies/g of sediment. At the same time, pcbA5 was enriched to only 105 copies/g of sediment. A survey for additional RDase genes revealed sequences similar to strain CG5's rd4 and rd8. In addition to demonstrating the PCB dechlorination potential of native microbial communities in contaminated freshwater sediments, our results suggest candidate functional genes with previously unexplored potential could serve as biomarkers of PCB dechlorination processes. [ABSTRACT FROM AUTHOR] more...- Published
- 2020
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9. Coupled Adsorption and Biodegradation of Trichloroethylene on Biochar from Pine Wood Wastes: A Combined Approach for a Sustainable Bioremediation Strategy
- Author
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Marta M. Rossi, Bruna Matturro, Neda Amanat, Simona Rossetti, and Marco Petrangeli Papini
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bioremediation ,adsorption ,biochar ,biodegradation ,reductive dechlorination ,Dehalococcoides mccartyi ,Biology (General) ,QH301-705.5 - Abstract
Towards chlorinated solvents, the effectiveness of the remediation strategy can be improved by combining a biological approach (e.g., anaerobic reductive dechlorination) with chemical/physical treatments (e.g., adsorption). A coupled adsorption and biodegradation (CAB) process for trichloroethylene (TCE) removal is proposed in a biofilm–biochar reactor (BBR) to assess whether biochar from pine wood (PWB) can support a dechlorinating biofilm by combining the TCE (100 µM) adsorption. The BBR operated for eight months in parallel with a biofilm reactor (BR)—no PWB (biological process alone), and with an abiotic biochar reactor (ABR)—no dechlorinating biofilm (only an adsorption mechanism). Two flow rates were investigated. Compared to the BR, which resulted in a TCE removal of 86.9 ± 11.9% and 78.73 ± 19.79%, the BBR demonstrated that PWB effectively adsorbs TCE and slows down the release of its intermediates. The elimination of TCE was quantitative, with 99.61 ± 0.79% and 99.87 ± 0.51% TCE removal. Interestingly, the biomarker of the reductive dechlorination process, Dehalococcoides mccartyi, was found in the BRR (9.2 × 105 16S rRNA gene copies/g), together with the specific genes tceA, bvcA, and vcrA (8.16 × 106, 1.28 × 105, and 8.01 × 103 gene copies/g, respectively). This study suggests the feasibility of biochar to support the reductive dechlorination of D. mccartyi, opening new frontiers for field-scale applications. more...
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- 2022
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10. Anaerobic degradation of 2,4,5-trichlorophenoxyacetic acid by enrichment cultures from freshwater sediments.
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Al-Fathi, Hassan, Koch, Mandy, Lorenz, Wilhelm G., and Lechner, Ute
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RIVER sediments ,SEDIMENTS ,ORGANIC acids ,BUTYRATES ,ELECTRON donors ,ELECTROPHILES ,CHLOROPHENOLS - Abstract
The anaerobic biodegradation of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) was investigated using enrichment cultures from freshwater sediments at two different sites in the region of Halle, central Germany. 2,4,5-T and different organic acids or hydrogen were added as possible electron acceptor and electron donors, respectively. The primary enrichment cultures from Saale river sediment completely degraded 2,4,5-T to 3-chlorophenol (3-CP) (major product) and 3,4-dichlorophenol (3,4-DCP) during a 28-day incubation period. Subcultures showed ether cleavage of 2,4,5-T to 2,4,5-trichlorophenol and its stoichiometric dechlorination to 3-CP only in the presence of butyrate. In contrast, the primary enrichment culture from sediment of Posthorn pond dechlorinated 2,4,5-T to 2,5-dichlorophenoxyacetic acid (2,5-D), which, in the presence of butyrate, was degraded further to products such as 3,4-DCP, 2,5-DCP, and 3CP, indicating ether cleaving activities and subsequent dechlorination steps. Experiments with pure cultures of Dehalococcoides mccartyi and Desulfitobacterium hafniense demonstrated their specific dechlorination steps within the overall 2,4,5-T degradation pathways. The results indicate that the route and efficiency of anaerobic 2,4,5-T degradation in the environment depend heavily on the microorganisms present and the availability of slowly fermentable organic compounds. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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11. Thermal proteome profiling allows quantitative assessment of interactions between tetrachloroethene reductive dehalogenase and trichloroethene.
- Author
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Türkowsky, Dominique, Lohmann, Patrick, Mühlenbrink, Marie, Schubert, Torsten, Adrian, Lorenz, Goris, Tobias, Jehmlich, Nico, and von Bergen, Martin
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PROTEOMICS , *EUKARYOTES , *LIGAND binding (Biochemistry) , *MELTING , *TRICHLOROETHYLENE - Abstract
Abstract Thermal proteome profiling (TPP) is increasingly applied in eukaryotes to investigate protein-ligand binding through protein melting curve shifts induced by the presence of a ligand. In anaerobic bacteria, identification of protein-substrate interactions is a major challenge. We applied TPP to Sulfurospirillum multivorans , which is able to use trichloroethene as electron acceptor for growth, to investigate the interaction of its tetrachloroethene reductive dehalogenase PceA with trichloroethene. Several modifications in the protocol (e.g., incubation under anaerobic conditions; increasing the temperature range up to 97 °C) extended the protein detection range and allowed the investigation of oxygen-sensitive proteins. Enzymatic reductive dehalogenation was prevented by omitting the electron donor during incubations. This enabled detecting the interaction of PceA with trichloroethene and confirmed that trichloroethene is a substrate of this enzyme. Interestingly, a putative response regulator showed a similar trend, which is the first biochemical hint for its proposed role in trichloroethene respiration. We proved that our TPP approach facilitates the identification of protein-substrate interactions of strictly anaerobic reductive dehalogenases and probably their regulators. This strategy can be used to identify yet unknown substrate specificities and possible signal-sensing proteins, and therefore has the potential to elucidate one of the unresolved fields in research on organohalide-respiring bacteria. Significance The assessment of enzyme-substrate or protein-ligand interactions in organohalide-respiring bacteria is a fundamental challenge. Thermal proteome profiling (TPP) allows elucidating proteome-wide thermal stability changes relying on the sensitivity of modern mass spectrometry. This gives access to the identification of interactions not detectable with other methods. In this TPP study, we demonstrate the interactions of a chlorinated substrate with a reductive dehalogenase and potentially with a response regulator, thereby supporting the response regulator's function in organohalide respiration. The strategy might also be applied to identify yet unknown substrates of other enzymes in bacteria which are difficult to investigate or for which only low amounts of biomass are available. The assessment of enzyme-substrate interactions, which might enable conclusions about enzyme specificities, represents a new application for TPP. Graphical abstract Unlabelled Image Highlights • Thermal proteome profiling (TPP) was modified for analyzing bacterial oxygen-sensitive enzymes. • Protein-trichloroethene interactions in organohalide-respiring Sulfurospirillum multivorans were identified. • Interaction of the tetrachloroethene reductive dehalogenase with trichloroethene was confirmed. • A first hint for the interaction of a response regulator and a chlorinated ethene was provided. [ABSTRACT FROM AUTHOR] more...
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- 2019
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12. Changes of the Proteome and Acetylome during Transition into the Stationary Phase in the Organohalide-Respiring Dehalococcoides mccartyi Strain CBDB1
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Franziska Greiner-Haas, Martin von Bergen, Gary Sawers, Ute Lechner, and Dominique Türkowsky
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Dehalococcoides mccartyi ,growth phase ,proteome ,organohalide respiration ,chlorobenzene ,mass spectrometry ,Biology (General) ,QH301-705.5 - Abstract
The strictly anaerobic bactGIerium Dehalococcoides mccartyi obligatorily depends on organohalide respiration for energy conservation and growth. The bacterium also plays an important role in bioremediation. Since there is no guarantee of a continuous supply of halogenated substrates in its natural environment, the question arises of how D. mccartyi maintains the synthesis and activity of dehalogenating enzymes under these conditions. Acetylation is a means by which energy-restricted microorganisms can modulate and maintain protein levels and their functionality. Here, we analyzed the proteome and Nε-lysine acetylome of D. mccartyi strain CBDB1 during growth with 1,2,3-trichlorobenzene as an electron acceptor. The high abundance of the membrane-localized organohalide respiration complex, consisting of the reductive dehalogenases CbrA and CbdbA80, the uptake hydrogenase HupLS, and the organohalide respiration-associated molybdoenzyme OmeA, was shown throughout growth. In addition, the number of acetylated proteins increased from 5% to 11% during the transition from the exponential to the stationary phase. Acetylation of the key proteins of central acetate metabolism and of CbrA, CbdbA80, and TatA, a component of the twin-arginine translocation machinery, suggests that acetylation might contribute to maintenance of the organohalide-respiring capacity of the bacterium during the stationary phase, thus providing a means of ensuring membrane protein integrity and a proton gradient. more...
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- 2021
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13. Multi-method assessment of the intrinsic biodegradation potential of an aquifer contaminated with chlorinated ethenes at an industrial area in Barcelona (Spain).
- Author
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Blázquez-Pallí, Natàlia, Rosell, Mònica, Varias, Joan, Bosch, Marçal, Soler, Albert, Vicent, Teresa, and Marco-Urrea, Ernest
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ENVIRONMENTAL remediation ,BIODEGRADATION ,AQUIFERS ,AQUIFER pollution ,ALKENES - Abstract
Abstract The bioremediation potential of an aquifer contaminated with tetrachloroethene (PCE) was assessed by combining hydrogeochemical data of the site, microcosm studies, metabolites concentrations, compound specific-stable carbon isotope analysis and the identification of selected reductive dechlorination biomarker genes. The characterization of the site through 10 monitoring wells evidenced that leaked PCE was transformed to TCE and cis -DCE via hydrogenolysis. Carbon isotopic mass balance of chlorinated ethenes pointed to two distinct sources of contamination and discarded relevant alternate degradation pathways in the aquifer. Application of specific-genus primers targeting Dehalococcoides mccartyi species and the vinyl chloride-to-ethene reductive dehalogenase vcrA indicated the presence of autochthonous bacteria capable of the complete dechlorination of PCE. The observed cis -DCE stall was consistent with the aquifer geochemistry (positive redox potentials; presence of dissolved oxygen, nitrate, and sulphate; absence of ferrous iron), which was thermodynamically favourable to dechlorinate highly chlorinated ethenes but required lower redox potentials to evolve beyond cis -DCE to the innocuous end product ethene. Accordingly, the addition of lactate or a mixture of ethanol plus methanol as electron donor sources in parallel field-derived anoxic microcosms accelerated dechlorination of PCE and passed cis -DCE up to ethene, unlike the controls (without amendments, representative of field natural attenuation). Lactate fermentation produced acetate at near-stoichiometric amounts. The array of techniques used in this study provided complementary lines of evidence to suggest that enhanced anaerobic bioremediation using lactate as electron donor source is a feasible strategy to successfully decontaminate this site. Graphical abstract Image 1 Highlights • Assessment of the biodegradation potential of an aquifer with chlorinated ethenes. • Hydrogeochemical data and CSIA describe aquifer and determine source apportionment. • DCE stall caused by lack of electron donors in groundwater. • Lactate-amended microcosms showed improved PCE-to-ethene dechlorination rates. • Dehalococcoides mccartyi and gene vcrA detected in field-derived cultures. The combination of complementary diagnostic techniques provides different lines of evidence for in situ bioremediation potential of a tetrachloroethene-contaminated aquifer. [ABSTRACT FROM AUTHOR] more...
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- 2019
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14. Impacts of low-temperature thermal treatment on microbial detoxification of tetrachloroethene under continuous flow conditions.
- Author
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Marcet, Tyler F., Cápiro, Natalie L., Yang, Yi, Löffler, Frank E., and Pennell, Kurt D.
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TETRACHLOROETHANE , *DECHLORINATION (Chemistry) , *BIOREMEDIATION , *HEAT treatment , *CONTINUOUS flow reactors - Abstract
Abstract Coupling in situ thermal treatment (ISTT) with microbial reductive dechlorination (MRD) has the potential to enhance contaminant degradation and reduce cleanup costs compared to conventional standalone remediation technologies. Impacts of low-temperature ISTT on Dehalococcoides mccartyi (Dhc), a relevant species in the anaerobic degradation of cis -1,2-dichloroethene (cis -DCE) and vinyl chloride (VC) to nontoxic ethene, were assessed in sand-packed columns under dynamic flow conditions. Dissolved tetrachloroethene (PCE; 258 ± 46 μM) was introduced to identical columns bioaugmented with the PCE-to-ethene dechlorinating consortium KB-1®. Initial column temperatures represented a typical aquifer (15 °C) or a site undergoing low-temperature ISTT (35 °C), and were subsequently increased to 35 and 74 °C, respectively, to assess temperature impacts on reductive dechlorination activity. In the 15 °C column, PCE was transformed primarily to cis -DCE (159 ± 2 μM), which was further degraded to VC (164 ± 3 μM) and ethene (30 ± 0 μM) within 17 pore volumes (PVs) after the temperature was increased to 35 °C. Regardless of the initial column temperature, ethene constituted >50 mol% of effluent degradation products in both columns after 73–74 PVs at 35 °C, indicating that MRD performance was greatly improved under low-temperature ISTT conditions. Increasing the temperature of the column initially at 35 °C resulted in continued VC and ethene production until a temperature of approximately 43 °C was reached, at which point Dhc activity substantially decreased. The abundance of the vcrA reductive dehalogenase gene exceeded that of the bvcA gene by 1–2.5 orders of magnitude at 15 °C, but this relationship inversed at temperatures >35 °C, suggesting Dhc strain-specific responses to temperature. These findings demonstrate improved MRD performance with low-temperature thermal treatment and emphasize potential synergistic effects at sites undergoing ISTT. Graphical abstract Image 1 Highlights • Microbial reductive dechlorination of PCE was enhanced at temperatures up to 43 °C. • Impacts of heating on Dhc dechlorination activity were strain-specific. • Dhc tolerates higher temperatures in flowing systems compared to batch reactors. • Ethene formation was not sensitive to the order of thermal-bio remedy application. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
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15. Anaerobic biotransformation of hexachlorocyclohexane isomers by Dehalococcoides species and an enrichment culture.
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Bashir, Safdar, Kuntze, Kevin, Vogt, Carsten, and Nijenhuis, Ivonne
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ANAEROBIC digestion ,BIOCONVERSION ,HEXACHLOROCYCLOHEXANES ,ISOMERS ,DEHALOCOCCOIDES - Abstract
The biotransformation of hexachlorocyclohexane isomers (HCH) by two Dehalococcoides mccartyi strains (195 and BTF08) and an enrichment culture was investigated and compared to conversion by the obligate anaerobic strain Clostridium pasteurianum strain DSMZ 525. The D. mccartyi strains preferentially transformed γ-HCH over α-HCH and δ-HCH isomers while β-HCH biotransformation was not significant. In case of the enrichment culture, γ-HCH was preferentially transformed over the δ-HCH, β-HCH and α-HCH isomers. Major observed metabolites in both cases were tetrachlorocyclohexene and as end products monochlorobenzene (MCB) and benzene. Dechlorination of the γ-HCH isomer was linked to an increase in cell numbers for strain 195. γ-HCH transformation was linked to considerable carbon stable isotope fractionation with the enrichment factor ε
c = − 5.5 ± 0.8‰ for D. mccartyi strain 195, εc = − 3.1 ± 0.4‰ for the enrichment culture and εc = − 4.1 ± 0.6‰ for co-metabolic transformation by C. pasteurianum. [ABSTRACT FROM AUTHOR] more...- Published
- 2018
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16. PCB dechlorination hotspots and reductive dehalogenase genes in sediments from a contaminated wastewater lagoon.
- Author
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Mattes, Timothy E., Ewald, Jessica M., Liang, Yi, Martinez, Andres, Awad, Andrew, Richards, Patrick, Hornbuckle, Keri C., and Schnoor, Jerald L.
- Subjects
POLYCHLORINATED biphenyls ,ORGANOCHLORINE compounds ,BIOACCUMULATION ,ENVIRONMENTAL toxicology ,SEWAGE - Abstract
Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants that are distributed worldwide. Although industrial PCB production has stopped, legacy contamination can be traced to several different commercial mixtures (e.g., Aroclors in the USA). Despite their persistence, PCBs are subject to naturally occurring biodegradation processes, although the microbes and enzymes involved are poorly understood. The biodegradation potential of PCB-contaminated sediments in a wastewater lagoon located in Virginia (USA) was studied. Total PCB concentrations in sediments ranged from 6.34 to 12,700 mg/kg. PCB congener profiles in sediment sample were similar to Aroclor 1248; however, PCB congener profiles at several locations showed evidence of dechlorination. The sediment microbial community structure varied among samples but was dominated by Proteobacteria and Firmicutes. The relative abundance of putative dechlorinating Chloroflexi (including Dehalococcoides sp.) was 0.01-0.19% among the sediment samples, with Dehalococcoides sp. representing 0.6-14.8% of this group. Other possible PCB dechlorinators present included the Clostridia and the Geobacteraceae. A PCR survey for potential PCB reductive dehalogenase genes (RDases) yielded 11 sequences related to RDase genes in PCB-respiring Dehalococcoides mccartyi strain CG5 and PCB-dechlorinating D. mccartyi strain CBDB1. This is the first study to retrieve potential PCB RDase genes from unenriched PCB-contaminated sediments. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
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17. Impact of magnetite nanoparticles on the syntrophic dechlorination of 1,2-dichloroethane.
- Author
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Leitão, Patrícia, Aulenta, Federico, Rossetti, Simona, Nouws, Henri P.A., and Danko, Anthony S.
- Subjects
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MAGNETITE , *DECHLORINATION (Chemistry) , *OXIDATION-reduction reaction , *ETHYLENE dichloride , *DEHALOCOCCOIDES - Abstract
In anaerobic environments microorganisms exchange electrons with community members and with soil and groundwater compounds. Interspecies electron transfer (IET) occurs by several mechanisms: diffusion of redox compounds or direct contact between cells. This latter mechanism may be facilitated by the presence of conductive nanoparticles (NP), possibly serving as electron conduits among microorganisms. Our study examined the effect of magnetite (Fe 3 O 4 ) NP on the dechlorination of 1,2-dichloroethane (1,2-DCA) by a mixed-culture. The addition of NP (170 mg L − 1 total Fe) enhanced the acetate-driven reductive dechlorination of 1,2-DCA to harmless ethene (via reductive dihaloelimination) up to 3.3-times (2.3 μeq L − 1 d − 1 vs. 0.7 μeq L − 1 d − 1 ), while decreasing the lag time by 0.8 times (23 days) when compared to unamended (magnetite-free) microcosms. Dechlorination activity was correlated with the abundance of Dehalococcoides mccartyi , which accounted up to 50% of total bacteria as quantified by CARD-FISH analysis, pointing to a key role of this microorganism in the process. Given the widespread abundance of conductive minerals in the environment, the results of this study may provide new insights into the fate of 1,2-DCA and suggest new tools for its remediation by linking biogeochemical mechanisms. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
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18. Most probable number with visual based LAMP for the quantification of reductive dehalogenase genes in groundwater samples.
- Author
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Kanitkar, Yogendra H., Stedtfeld, Robert D., Hatzinger, Paul B., Hashsham, Syed A., and Cupples, Alison M.
- Subjects
- *
DEHALOCOCCOIDES , *BACTERIAL genes , *DEHALOGENASES , *GENE amplification , *DNA glycosylases , *BACTERIA - Abstract
The remediation of chlorinated solvent contaminated sites frequently involves bioaugmentation with mixed cultures containing Dehalococcoides mccartyi . Their activity is then examined by quantifying reductive dehalogenase (RDase) genes. Recently, we described a rapid, low cost approach, based on loop mediated isothermal amplification (LAMP), which allowed for the visual detection of RDase genes from groundwater. In that study, samples were concentrated (without DNA extraction), incubated in a water bath (avoiding the use of a thermal cycler) and amplification was visualized by the addition of SYBR green (post incubation). Despite having a detection limit less than the threshold recommended for effective remediation, the application of the assay was limited because of the semi-quantitative nature of the data. Moreover, the assay was prone to false positives due to the aerosolization of amplicons. In this study, deoxyuridine triphosphate (dUTP) and uracil DNA glycosylase (UNG) were incorporated into the assay to reduce the probability of false positives. Optimization experiments revealed a UNG concentration of 0.2 units per reaction was adequate for degrading trace levels of AUGC based contamination (~ 1.4 × 10 4 gene copies/reaction) without significant changes to the detection limit (~ 100 gene copies/reaction). Additionally, the optimized assay was used with the most probable number (MPN) method to quantify RDase genes ( vcrA and tceA ) in multiple groundwater samples from a chlorinated solvent contaminated site. Using this approach, gene concentrations were significantly correlated to concentrations obtained using traditional methods (qPCR and DNA templates). Although the assay underestimated RDase genes concentrations, a strong correlation (R 2 = 0.78 and 0.94) was observed between the two data sets. The regression equations obtained will be valuable to determine gene copies in groundwater using the newly developed, low cost and time saving method. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
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19. Oxygen exposure effects on the dechlorinating activities of a trichloroethene-dechlorination microbial consortium.
- Author
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Liu, Na, Li, Haijun, Li, Mengyan, Ding, Longzhen, Weng, Chih-Huang, and Dong, Cheng-Di
- Subjects
- *
DECHLORINATION (Chemistry) , *TRICHLOROETHYLENE , *MICROBIAL ecology , *DEHALOCOCCOIDES , *BIOTRANSFORMATION (Metabolism) , *POLYMERASE chain reaction - Abstract
The aim of this work was to study the effects of the presence of oxygen on the dechlorination of trichloroethene by a microbial consortium containing D. mccartyi . The 16S rRNA and reductive dechlorination genes of the functional bacteria and the non-dechlorinators were monitored. Exposing the consortium to oxygen altered the overall biotransformation rate of the dechlorination process, biotransformation processes prolonged with oxygen concentrations changing from 0 to 7.2 mg/L, however, trichloroethylene was eventually dechlorinated to ethene. The qPCR analyses revealed that the D. mccartyi strains containing the tceA gene were less sensitive to exposure to oxygen than were the D. mccartyi strains containing the vcrA gene. High-throughput sequencing by Illumina MiSeq indicated that the non-dechlorinating organisms were probably crucial to scavenge the oxygen to protect D. mccartyi from being damaged. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
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20. Genomic characterization of Dehalococcoides mccartyi strain 11a5 reveals a circular extrachromosomal genetic element and a new tetrachloroethene reductive dehalogenase gene.
- Author
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Siyan Zhao, Chang Ding, and Jianzhong He
- Subjects
- *
DEHALOCOCCOIDES , *ANAEROBIC bacteria , *BACTERIAL genomes , *MICROBIAL genomes , *PROKARYOTIC genomes , *TETRACHLOROETHYLENE , *CHLOROHYDROCARBONS - Abstract
Dehalococcoides mccartyi exhibits versatile capabilities to respire halogenated compounds under anaerobic conditions. In this study, we report the assembly and annotation of the complete genome of a chloroethene dechlorinating D. mccartyi strain 11a5. Bearing a 1461 973 base-pair chromosome, strain 11a5 distinguishes itself from other D. mccartyi strains by possessing a 5940 base-pair circular extrachromosomal genetic element which contains a reductive dehalogenase homolog. The whole genome of strain 11a5 harbors 31 putative reductive dehalogenase genes. Through transcriptional and proteomic analyses, we identified a new tetrachloroethene (PCE) reductive dehalogenase, PteA (11a5 1355), which catalyzes reductive dechlorination from PCE to trichloroethene (TCE) and shares only 38% similarity in amino acid sequence with its closest relative PceA in D. mccartyi strain 195. The acquisition of the genome of strain 11a5 enlarged the database of D. mccartyi and enriched our understanding of this unique species, among which, the identification of a new PCE reductive dehalogenase can assist in understanding PCE dechlorination process. In addition, the discovery of the circular extrachromosomal genetic element in strain 11a5 may provide insights to investigate how reductive dehalogenase homologous genes are transferred and carried by organohalide respiring bacteria. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
21. Dechlorination of three tetrachlorobenzene isomers by contaminated harbor sludge-derived enrichment cultures follows thermodynamically favorable reactions.
- Author
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Lu, Yue, Ramiro-Garcia, Javier, Vandermeeren, Pieter, Herrmann, Steffi, Cichocka, Danuta, Springael, Dirk, Atashgahi, Siavash, and Smidt, Hauke
- Subjects
- *
DECHLORINATION (Chemistry) , *TETRACHLOROBENZENE , *ISOMERS , *SLUDGE management , *GEOBACTER - Abstract
Dechlorination patterns of three tetrachlorobenzene isomers, 1,2,3,4-, 1,2,3,5-, and 1,2,4,5-TeCB, were studied in anoxic microcosms derived from contaminated harbor sludge. The removal of doubly, singly, and un-flanked chlorine atoms was noted in 1,2,3,4- and 1,2,3,5-TeCB fed microcosms, whereas only singly flanked chlorine was removed in 1,2,4,5-TeCB microcosms. The thermodynamically more favorable reactions were selectively followed by the enriched cultures with di- and/or mono-chlorobenzene as the main end products of the reductive dechlorination of all three isomers. Based on quantitative PCR analysis targeting 16S rRNA genes of known organohalide-respiring bacteria, the growth of Dehalococcoides was found to be associated with the reductive dechlorination of all three isomers, while growth of Dehalobacter, another known TeCB dechlorinator, was only observed in one 1,2,3,5-TeCB enriched microcosm among biological triplicates. Numbers of Desulfitobacterium and Geobacter as facultative dechlorinators were rather stable suggesting that they were not (directly) involved in the observed TeCB dechlorination. Bacterial community profiling suggested bacteria belonging to the phylum Bacteroidetes and the order Clostridiales as well as sulfate-reducing members of the class Deltaproteobacteria as putative stimulating guilds that provide electron donor and/or organic cofactors to fastidious dechlorinators. Our results provide a better understanding of thermodynamically preferred TeCB dechlorinating pathways in harbor environments and microbial guilds enriched and active in anoxic TeCB dechlorinating microcosms. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
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22. Microbiome dynamics of a polychlorobiphenyl (PCB) historically contaminated marine sediment under conditions promoting reductive dechlorination
- Author
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Bruna Matturro, Carla Ubaldi, and Simona Rossetti
- Subjects
Epsilonproteobacteria ,marine sediments ,microbiome ,Reductive dechlorination ,Next generation sequencing (NGS) ,Dehalococcoides mccartyi ,Microbiology ,QR1-502 - Abstract
The toxicity of polychlorinated biphenyls (PCB) can be efficiently reduced in contaminated marine sediments through the reductive dechlorination process lead by anaerobic organohalide bacteria. Although the process has been extensively investigated on PCB-spiked sediments, the knowledge on the identity and metabolic potential of PCB-dechlorinating microorganisms in real contaminated matrix is still limited. Aim of this study was to explore the composition and the dynamics of the microbial communities of the marine sediment collected from one of the largest Sites of National Interest (SIN) in Italy (Mar Piccolo, Taranto) under conditions promoting the PCBs reductive dechlorination. A long-term microcosm study revealed that autochthonous bacteria were able to sustain the PCB dechlorination at a high extent and the successive addition of an external fermentable organic substrate (lactate) caused the further depletion of the high-chlorinated PCBs (up to 70%). Next Generation Sequencing was used to describe the core microbiome of the marine sediment and to follow the changes caused by the treatments. OTUs affiliated to sulfur-oxidizing ε-proteobacteria, Sulfurovum and Sulfurimonas, were predominant in the original sediment and increased up to 60% of total OTUs after lactate addition. Other OTUs detected in the sediment were affiliated to sulfate reducing (δ-proteobacteria) and to organohalide respiring bacteria within Chloroflexi phylum mainly belonging to Dehalococcoidia class. Among others, Dehalococcoides mccartyi was enriched during the treatments even though the screening of the specific reductive dehalogenase genes revealed the occurrence of undescribed strains, which deserve further investigations. Overall, this study highlighted the potential of members of Dehalococcoidia class in reducing the contamination level of the marine sediment from Mar Piccolo with relevant implications on the selection of sustainable bioremediation strategies to clean-up the site. more...
- Published
- 2016
- Full Text
- View/download PDF
23. Impact of Ammonium on Syntrophic Organohalide-Respiring and Fermenting Microbial Communities
- Author
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Anca G. Delgado, Devyn Fajardo-Williams, Kylie L. Kegerreis, Prathap Parameswaran, and Rosa Krajmalnik-Brown
- Subjects
Dehalococcoides mccartyi ,Geobacter ,ammonia ,fermentation ,organohalide respiration ,trichloroethene ,Microbiology ,QR1-502 - Abstract
ABSTRACT Syntrophic interactions between organohalide-respiring and fermentative microorganisms are critical for effective bioremediation of halogenated compounds. This work investigated the effect of ammonium concentration (up to 4 g liter−1 NH4+-N) on trichloroethene-reducing Dehalococcoides mccartyi and Geobacteraceae in microbial communities fed lactate and methanol. We found that production of ethene by D. mccartyi occurred in mineral medium containing ≤2 g liter−1 NH4+-N and in landfill leachate. For the partial reduction of trichloroethene (TCE) to cis-dichloroethene (cis-DCE) at ≥1 g liter−1 NH4+-N, organohalide-respiring dynamics shifted from D. mccartyi and Geobacteraceae to mainly D. mccartyi. An increasing concentration of ammonium was coupled to lower metabolic rates, longer lag times, and lower gene abundances for all microbial processes studied. The methanol fermentation pathway to acetate and H2 was conserved, regardless of the ammonium concentration provided. However, lactate fermentation shifted from propionic to acetogenic at concentrations of ≥2 g liter−1 NH4+-N. Our study findings strongly support a tolerance of D. mccartyi to high ammonium concentrations, highlighting the feasibility of organohalide respiration in ammonium-contaminated subsurface environments. IMPORTANCE Contamination with ammonium and chlorinated solvents has been reported in numerous subsurface environments, and these chemicals bring significant challenges for in situ bioremediation. Dehalococcoides mccartyi is able to reduce the chlorinated solvent trichloroethene to the nontoxic end product ethene. Fermentative bacteria are of central importance for organohalide respiration and bioremediation to provide D. mccartyi with H2, their electron donor, acetate, their carbon source, and other micronutrients. In this study, we found that high concentrations of ammonium negatively correlated with rates of trichloroethene reductive dehalogenation and fermentation. However, detoxification of trichloroethene to nontoxic ethene occurred even at ammonium concentrations typical of those found in animal waste (up to 2 g liter−1 NH4+-N). To date, hundreds of subsurface environments have been bioremediated through the unique metabolic capability of D. mccartyi. These findings extend our knowledge of D. mccartyi and provide insight for bioremediation of sites contaminated with chlorinated solvents and ammonium. more...
- Published
- 2016
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24. Synergistic Zerovalent Iron (Fe0) and Microbiological Trichloroethene and Perchlorate Reductions Are Determined by the Concentration and Speciation of Fe
- Author
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Aatikah Mouti, Gregory V. Lowry, Rosa Krajmalnik-Brown, Srivatsan Mohana Rangan, Anca G. Delgado, and Laurie LaPat-Polasko
- Subjects
Zerovalent iron ,media_common.quotation_subject ,Dehalococcoides mccartyi ,General Chemistry ,010501 environmental sciences ,01 natural sciences ,Anoxic waters ,Perchlorate ,chemistry.chemical_compound ,Speciation ,Bioremediation ,chemistry ,Environmental chemistry ,Environmental Chemistry ,0105 earth and related environmental sciences ,media_common - Abstract
Trichloroethene (TCE) and perchlorate (ClO4–) are cocontaminants at multiple Superfund sites. Fe0 is often used during TCE bioremediation with Dehalococcoides mccartyi to establish anoxic condition... more...
- Published
- 2020
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- View/download PDF
25. Dehalococcoides mccartyi Strain GEO12 Has a Natural Tolerance to Chloroform Inhibition
- Author
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Jianzhong He, Chang Ding, and Matthew J. Rogers
- Subjects
chemistry.chemical_compound ,Bioremediation ,Chloroform ,chemistry ,Strain (chemistry) ,Dehalococcoides mccartyi ,Environmental Chemistry ,General Chemistry ,010501 environmental sciences ,01 natural sciences ,0105 earth and related environmental sciences ,Microbiology - Abstract
Cocontamination by chloroform and chloroethenes often confounds bioremediation efforts. Here, we describe Dehalococcoides mccartyi strain GEO12 that dechlorinates trichloroethene to ethene in 14 μM... more...
- Published
- 2020
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- View/download PDF
26. Dual C–Cl Isotope Analysis for Characterizing the Reductive Dechlorination of α- and γ-Hexachlorocyclohexane by Two Dehalococcoides mccartyi Strains and an Enrichment Culture
- Author
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Ivonne Nijenhuis, Hans H. Richnow, Yaqing Liu, Julian Renpenning, and Jia Liu
- Subjects
Chemistry ,Dehalococcoides mccartyi ,Halogenation ,General Chemistry ,010501 environmental sciences ,01 natural sciences ,Enrichment culture ,Human health ,Environmental chemistry ,Reductive dechlorination ,Environmental Chemistry ,γ-hexachlorocyclohexane ,0105 earth and related environmental sciences ,Isotope analysis - Abstract
Hexachlorocyclohexanes (HCHs) are persistent organic contaminants that threaten human health. Microbial reductive dehalogenation is one of the most important attenuation processes in contaminated e... more...
- Published
- 2020
- Full Text
- View/download PDF
27. Completely dechlorinating of trichloroethene by a Dehalococcoides mccartyi-containing microbial consortium in the absence of cobalamin
- Author
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Yalu Du, Na Liu, Shanming Wei, Haijun Li, and Guantao Ding
- Subjects
chemistry.chemical_compound ,Chemistry ,Dehalococcoides mccartyi ,Microbial consortium ,Cobalamin ,Microbiology - Abstract
Completely dechlorinating of trichloroethene (TCE) by Dehalococcoides mccartyi (D.mccartyi) is catalyzed by reductive dehalogenases (RDases) which possess cobalamin as the crucial cofactor, whereas virtually all pure D.mccartyi strains isolated thus far are corrinoid auxotrophs. Exogenous addition of commercially available cobalamin for real TCE-contaminated site decontamination is deemed to be unrealistic. In this study, TCE reduction by a D.mccartyi-containing microbial consortium utilizing biosynthetic cobalamin generated by interior corrinoid-producing organisms within this mixed consortia was studied. The results confirmed that subcultures with exogenous cobalamin omitting from the medium apparently were impervious and enabled to successively metabolize TCE to non-chlorinated ethene. The 2-bromoethanesulfonate and ampicillin resistance tests results suggested that bacteria (particularly certain ampicillin-sensitive ones) rather than methanogenic archaea within this microbial consortium were responsible for biosynthesizing cobalamin. Moreover, relative stable Ɛ-carbon values of TCE among treatments in disregard of whether exogenous cobalamin or selective inhibitors were existed in the medium also speculated that cobalamin biosynthesized by these organisms was enable to uptake and utilize by D.mccartyi for RDases synthesis and eventually participated in TCE reduction. Finally, the Illumina MiSeq sequencing analysis indicated that Desulfitobacterium and Acetobacterium in this microbial consortium probably both were in charge of de novo cobalamin biosynthesis to fulfillment the requirements of D.mccartyi for TCE metabolism. more...
- Published
- 2021
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28. Microbial Reductive Dechlorination by a Commercially Available Dechlorinating Consortium Is Not Inhibited by Perfluoroalkyl Acids (PFAAs) at Field-Relevant Concentrations.
- Author
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Hnatko JP, Liu C, Elsey JL, Dong S, Fortner JD, Pennell KD, Abriola LM, and Cápiro NL
- Subjects
- Ethylenes metabolism, Biodegradation, Environmental, Chloroflexi genetics, Chloroflexi metabolism, Vinyl Chloride metabolism, Fluorocarbons, Trichloroethylene metabolism
- Abstract
Perfluoroalkyl acids (PFAAs) have been shown to inhibit biodegradation (i.e., organohalide respiration) of chlorinated ethenes. The potential negative impacts of PFAAs on microbial species performing organohalide respiration, particularly Dehalococcoides mccartyi ( Dhc ), and the efficacy of in situ bioremediation are a critical concern for comingled PFAA-chlorinated ethene plumes. Batch reactor (no soil) and microcosm (with soil) experiments, containing a PFAA mixture and bioaugmented with KB-1, were completed to assess the impact of PFAAs on chlorinated ethene organohalide respiration. In batch reactors, PFAAs delayed complete biodegradation of cis -1,2-dichloroethene ( cis -DCE) to ethene. Maximum substrate utilization rates (a metric for quantifying biodegradation rates) were fit to batch reactor experiments using a numerical model that accounted for chlorinated ethene losses to septa. Fitted values for cis -DCE and vinyl chloride biodegradation were significantly lower ( p < 0.05) in batch reactors containing ≥50 mg/L PFAAs. Examination of reductive dehalogenase genes implicated in ethene formation revealed a PFAA-associated change in the Dhc community from cells harboring the vcrA gene to those harboring the bvcA gene. Organohalide respiration of chlorinated ethenes was not impaired in microcosm experiments with PFAA concentrations of 38.7 mg/L and less, suggesting that a microbial community containing multiple strains of Dhc is unlikely to be inhibited by PFAAs at lower, environmentally relevant concentrations. more...
- Published
- 2023
- Full Text
- View/download PDF
29. Widespread Distribution of Dehalococcoides mccartyi in the Houston Ship Channel and Galveston Bay, Texas, Sediments and the Potential for Reductive Dechlorination of PCDD/F in an Estuarine Environment.
- Author
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Hieke, Anne-Sophie, Brinkmeyer, Robin, Yeager, Kevin, Schindler, Kimberly, Zhang, Saijin, Xu, Chen, Louchouarn, Patrick, and Santschi, Peter
- Abstract
Sediments in the Houston Ship Channel and upper Galveston Bay, Texas, USA, are polluted with polychlorinated dibenzo- p-dioxins/furans (PCDD/F; ≤46,000 ng/kg dry weight (wt.)) with 2,3,7,8-tetrachlorodibenzo -p-dioxin (TCDD), the most toxic congener, contributing >50 % of the total toxic equivalents (TEQ) at most locations. We measured PCDD/F concentrations in sediments and evaluated the potential for enhanced in situ biodegradation by surveying for Dehalococcoides mccartyi, an obligate organohalide respiring bacterium. Dehalococcoides spp. (98 % similar to D. mccartyi) and 22 other members of the class Dehalococcoidia were predominant 16S ribosomal RNA (rRNA) phylotypes. Dehalococcoides spp. were also present in the active fraction of the bacterial community. Presence/absence PCR screening detected D. mccartyi in sediment cores and sediment grab samples having at least 1 ng/kg dry wt. TEQ at salinities ranging from 0.6 to 19.5 PSU, indicating that they are widespread in the estuarine environment. Organic carbon-only and organic carbon + sulfate-amended sediment microcosm experiments resulted in ∼60 % reduction of ambient 2,3,7,8-TCDD in just 24 months leading to reductions in total TEQs by 38.4 and 45.0 %, respectively, indicating that 2,3,7,8-TCDD degradation is occurring at appreciable rates. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
30. First evidence on the occurrence and dynamics of Dehalococcoides mccartyi PCB-dechlorinase genes in marine sediment during Aroclor1254 reductive dechlorination.
- Author
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Matturro, B., Di Lenola, M., Ubaldi, C., and Rossetti, S.
- Subjects
DEHALOCOCCOIDES ,MARINE sediments ,DECHLORINATION (Chemistry) ,POLYCHLORINATED biphenyls ,ENVIRONMENTAL sampling - Abstract
The present study evaluates the PCB-dehalorespiring capabilities and dynamics of indigenous Dehalococcoides mccartyi population in a PCB contaminated marine sediment. Specialized PCB-dechlorinase genes pcbA1 , pcbA4 and pcbA5 previously characterized in pure cultures of D. mccartyi , were here found for the first time in environmental samples. Reductive dechlorination was stimulated by spiking Aroclor1254 to the sediment and by imposing strictly anaerobic conditions both with and without bioaugmentation with a Dehalococcoides mccartyi enrichment culture. In line with the contaminant dechlorination kinetics, Dehalococcoides population increased during the entire incubation period showing growth yields of 4.94E + 07 Dehalococcoides per μmol Cl − 1 and 7.30E + 05 Dehalococcoides per μmol Cl − 1 in the marine sediment with and without bioaugmentation respectively. The pcbA4 and pcbA5 dechlorinase genes, and to a lesser extent pcbA1 gene, were enriched during the anaerobic incubation suggesting their role in Aroclor1254 dechlorination under salinity conditions. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
31. Microbiome Dynamics of a Polychlorobiphenyl (PCB) Historically Contaminated Marine Sediment under Conditions Promoting Reductive Dechlorination.
- Author
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Matturro, Bruna, Ubaldi, Carla, Rossetti, Simona, Hemme, Christopher L., and Petruccioli, Maurizio
- Subjects
POLYCHLORINATED biphenyls ,DECHLORINATION (Chemistry) ,TOXICITY testing - Abstract
The toxicity of polychlorinated biphenyls (PCB) can be efficiently reduced in contaminated marine sediments through the reductive dechlorination (RD) process lead by anaerobic organohalide bacteria. Although the process has been extensively investigated on PCB-spiked sediments, the knowledge on the identity and metabolic potential of PCB-dechlorinating microorganisms in real contaminated matrix is still limited. Aim of this study was to explore the composition and the dynamics of the microbial communities of the marine sediment collected from one of the largest Sites of National Interest (SIN) in Italy (Mar Piccolo, Taranto) under conditions promoting the PCBs RD. A long-term microcosm study revealed that autochthonous bacteria were able to sustain the PCB dechlorination at a high extent and the successive addition of an external fermentable organic substrate (lactate) caused the further depletion of the high-chlorinated PCBs (up to 70%). Next Generation Sequencing was used to describe the core microbiome of the marine sediment and to follow the changes caused by the treatments. OTUs affiliated to sulfur-oxidizing +-proteobacteria, Sulfurovum, and Sulfurimonas, were predominant in the original sediment and increased up to 60% of total OTUs after lactate addition. Other OTUs detected in the sediment were affiliated to sulfate reducing (d-proteobacteria) and to organohalide respiring bacteria within Chloroflexi phylum mainly belonging to Dehalococcoidia class. Among others, Dehalococcoides mccartyi was enriched during the treatments even though the screening of the specific reductive dehalogenase genes revealed the occurrence of undescribed strains, which deserve further investigations. Overall, this study highlighted the potential of members of Dehalococcoidia class in reducing the contamination level of the marine sediment from Mar Piccolo with relevant implications on the selection of sustainable bioremediation strategies to clean-up the site. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
32. Enrichment of Dehalococcoides mccartyi spp. from a municipal activated sludge during AQDS-mediated bioelectrochemical dechlorination of 1,2-dichloroethane to ethene.
- Author
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Leitão, Patrícia, Rossetti, Simona, Danko, Anthony S., Nouws, Henri, and Aulenta, Federico
- Subjects
- *
DEHALOCOCCOIDES , *ACTIVATED sludge process , *BIOELECTROCHEMISTRY , *DECHLORINATION (Chemistry) , *ETHYLENE dichloride , *ALKENES - Abstract
The application of bioelectrochemical systems (BES) for the treatment of chloroethanes has been so far limited, in spite of the high frequency that these contaminants are detected at contaminated sites. This work studied the biodegradation of 1,2-dichloroethane (1,2-DCA) in a lab-scale BES, inoculated with a municipal activated sludge and operated under a range of conditions, spanning from oxidative to reductive, both in the presence and in the absence of the humic acid analogue anthraquinone-2,6-disulfonate (AQDS) as a redox mediator. The results showed stable dechlorination of 1,2-DCA to ethene (up to 65 ± 5 μmol/L d), when the BES was operated at a set potential of −300 mV vs. SHE, in the presence of AQDS. Sustained filled-and-draw operation resulted in the enrichment of Dehalococcoides mccartyi . The results of this work provide new insights into the applicability of BES for groundwater remediation and the potential interaction between biogeochemistry and 1,2-DCA in humics-rich contaminated aquifers. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
33. Polychlorinated biphenyl (PCB) anaerobic degradation in marine sediments: microcosm study and role of autochthonous microbial communities.
- Author
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Matturro, Bruna, Ubaldi, Carla, Grenni, Paola, Caracciolo, Anna, and Rossetti, Simona
- Subjects
MARINE sediment pollution ,BIODEGRADATION of polychlorinated biphenyls ,DEHALOCOCCOIDES ,MARINE bioremediation - Abstract
Polychlorobiphenyl (PCB) biodegradation was followed for 1 year in microcosms containing marine sediments collected from Mar Piccolo (Taranto, Italy) chronically contaminated by this class of hazardous compounds. The microcosms were performed under strictly anaerobic conditions with or without the addition of Dehalococcoides mccartyi, the main microorganism known to degrade PCBs through the anaerobic reductive dechlorination process. Thirty PCB congeners were monitored during the experiments revealing that the biodegradation occurred in all microcosms with a decrease in hepta-, hexa-, and penta-chlorobiphenyls (CBs) and a parallel increase in low chlorinated PCBs (tri-CBs and tetra-CBs). The concentrations of the most representative congeners detected in the original sediment, such as 245-245-CB and 2345-245-CB, and of the mixture 2356-34-CB+234-245-CB, decreased by 32.5, 23.8, and 46.7 %, respectively, after only 70 days of anaerobic incubation without any bioaugmentation treatment. Additionally, the structure and population dynamics of the microbial key players involved in the biodegradative process and of the entire mixed microbial community were accurately defined by Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) in both the original sediment and during the operation of the microcosm. The reductive dehalogenase genes of D. mccartyi, specifically involved in PCB dechlorination, were also quantified using real-time PCR (qPCR). Our results demonstrated that the autochthonous microbial community living in the marine sediment, including D. mccartyi (6.32E+06 16S rRNA gene copy numbers g sediment), was able to efficiently sustain the biodegradation of PCBs when controlled anaerobic conditions were imposed. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
34. Reductive dechlorination of tetrachloroethene in marine sediments: Biodiversity and dehalorespiring capabilities of the indigenous microbes.
- Author
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Matturro, B., Presta, E., and Rossetti, S.
- Subjects
- *
CHEMICAL reduction , *DECHLORINATION (Chemistry) , *TETRACHLOROETHYLENE , *MARINE sediments , *BIODIVERSITY - Abstract
Chlorinated compounds pose environmental concerns due to their toxicity and wide distribution in several matrices. Microorganisms specialized in leading anaerobic reductive dechlorination (RD) processes, including Dehalococcoides mccartyi ( Dhc ), are able to reduce chlorinated compounds to harmless products or to less toxic forms. Here we report the first detailed study dealing with the RD potential of heavy polluted marine sediment by evaluating the biodegradation kinetics together with the composition, dynamics and activity of indigenous microbial population. A microcosm study was conducted under strictly anaerobic conditions on marine sediment collected near the marine coast of Sarno river mouth, one of the most polluted river in Europe. Tetrachloroethene (PCE), used as model pollutant, was completely converted to ethene within 150 days at reductive dechlorination rate equal to 0.016 meq L − 1 d − 1 . Consecutive spikes of PCE allowed increasing the degradation kinetics up to 0.1 meq L − 1 d − 1 within 20 days. Strictly anaerobiosis and repeated spikes of PCE stimulated the growth of indigenous Dhc cells (growth yield of ~ 7.0E + 07 Dhc cells per μM Cl − 1 released). Dhc strains carrying the reductive dehalogenase genes tceA and vcrA were detected in the original marine sediment and their number increased during the treatment as demonstrated by the high level of tceA expression at the end of the microcosm study (2.41E + 05 tceA gene transcripts g − 1 ). Notably, the structure of the microbial communities was fully described by Catalysed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) as wells as the dynamics of the dechlorinating bacteria during the microcosms operation. Interestingly, a direct role of Dhc cells was ascertained suggesting the existence of strains adapted at salinity conditions. Additionally, non- Dhc Chloroflexi were retrieved in the original sediment and were kept stable over time suggesting their likely flanking role of the RD process. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
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35. Impact of Fixed Nitrogen Availability on Dehalococcoides mccartyi Reductive Dechlorination Activity
- Author
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Dora Taggart, Frank E. Löffler, Birthe V. Kjellerup, Karuna Chourey, Devrim Kaya, and Robert L. Hettich
- Subjects
inorganic chemicals ,Dehalococcoides mccartyi ,food and beverages ,chemistry.chemical_element ,General Chemistry ,010501 environmental sciences ,01 natural sciences ,Nitrogen ,Biostimulation ,chemistry ,Environmental chemistry ,Nitrogen fixation ,Reductive dechlorination ,Environmental Chemistry ,0105 earth and related environmental sciences - Abstract
Biostimulation to promote reductive dechlorination is widely practiced, but the value of adding an exogenous nitrogen (N) source (e.g., NH4+) during treatment is unclear. This study investigates th... more...
- Published
- 2019
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36. Decoupling Fe 0 Application and Bioaugmentation in Space and Time Enables Microbial Reductive Dechlorination of Trichloroethene to Ethene: Evidence from Soil Columns.
- Author
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Mohana Rangan S, Rao S, Robles A, Mouti A, LaPat-Polasko L, Lowry GV, Krajmalnik-Brown R, and Delgado AG
- Subjects
- Soil, Biodegradation, Environmental, Solvents, Trichloroethylene analysis, Chloroflexi
- Abstract
Fe
0 is a powerful chemical reductant with applications for remediation of chlorinated solvents, including tetrachloroethene and trichloroethene. Its utilization efficiency at contaminated sites is limited because most of the electrons from Fe0 are channeled to the reduction of water to H2 rather than to the reduction of the contaminants. Coupling Fe0 with H2 -utilizing organohalide-respiring bacteria (i.e., Dehalococcoides mccartyi ) could enhance trichloroethene conversion to ethene while maximizing Fe0 utilization efficiency. Columns packed with aquifer materials have been used to assess the efficacy of a treatment combining in space and time Fe0 and a D. mccartyi -containing culture (bioaugmentation). To date, most column studies documented only partial conversion of the solvents to chlorinated byproducts, calling into question the feasibility of Fe0 to promote complete microbial reductive dechlorination. In this study, we decoupled the application of Fe0 in space and time from the addition of organic substrates and D. mccartyi -containing cultures. We used a column containing soil and Fe0 (at 15 g L-1 in porewater) and fed it with groundwater as a proxy for an upstream Fe0 injection zone dominated by abiotic reactions and biostimulated/bioaugmented soil columns (Bio-columns) as proxies for downstream microbiological zones. Results showed that Bio-columns receiving reduced groundwater from the Fe0 -column supported microbial reductive dechlorination, yielding up to 98% trichloroethene conversion to ethene. The microbial community in the Bio-columns established with Fe0 -reduced groundwater also sustained trichloroethene reduction to ethene (up to 100%) when challenged with aerobic groundwater. This study supports a conceptual model where decoupling the application of Fe0 and biostimulation/bioaugmentation in space and/or time could augment microbial trichloroethene reductive dechlorination, particularly under oxic conditions. more...- Published
- 2023
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37. Spatial and temporal dynamics of organohalide-respiring bacteria in a heterogeneous PCE–DNAPL source zone.
- Author
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Cápiro, Natalie L., Löffler, Frank E., and Pennell, Kurt D.
- Subjects
- *
NONAQUEOUS phase liquids , *BACTERIOPHAGES , *ANTIBIOTICS , *PROKARYOTES , *DEHALOCOCCOIDES - Abstract
Effective treatment of sites contaminated with dense non-aqueous phase liquids (DNAPLs) requires detailed understanding of the microbial community responses to changes in source zone strength and architecture. Changes in the spatial and temporal distributions of the organohalide-respiring Dehalococcoides mccartyi ( Dhc ) strains and Geobacter lovleyi strain SZ ( Geo SZ) were examined in a heterogeneous tetrachloroethene- (PCE-) DNAPL source zone within a two-dimensional laboratory-scale aquifer flow cell. As part of a combined remedy approach, flushing with 2.3 pore volumes (PVs) of 4% (w/w) solution of the nonionic, biodegradable surfactant Tween® 80 removed 55% of the initial contaminant mass, and resulted in a PCE–DNAPL distribution that contained 51% discrete ganglia and 49% pools (ganglia-to-pool ratio of 1.06). Subsequent bioaugmentation with the PCE-to-ethene-dechlorinating consortium BDI-SZ resulted in cis -1,2-dichloroethene ( cis -DCE) formation after 1 PV (ca. 7 days), while vinyl chloride (VC) and ethene were detected 10 PVs after bioaugmentation. Maximum ethene yields (ca. 90 μM) within DNAPL pool and ganglia regions coincided with the detection of the vcrA reductive dehalogenase (RDase) gene that exceeded the Dhc 16S rRNA genes by 2.0 ± 1.3 and 4.0 ± 1.7 fold in the pool and ganglia regions, respectively. Dhc and Geo SZ cell abundance increased by up to 4 orders-of-magnitude after 28 PVs of steady-state operation, with 1 to 2 orders-of-magnitude increases observed in close proximity to residual PCE–DNAPL. These observations suggest the involvement of these dechlorinators the in observed PCE dissolution enhancements of up to 2.3 and 6.0-fold within pool and ganglia regions, respectively. Analysis of the solid and aqueous samples at the conclusion of the experiment revealed that the highest VC (≥ 155 μM) and ethene (≥ 65 μM) concentrations were measured in zones where Dhc and Geo SZ were predominately attached to the solids. These findings demonstrate dynamic responses of organohalide-respiring bacteria in a heterogeneous DNAPL source zone, and emphasize the influence of source zone architecture on bioremediation performance. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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38. Enumeration of Organohalide Respirers in Municipal Wastewater Anaerobic Digesters.
- Author
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Smith, Bryan J. K., Boothe, Melissa A., Fiddler, Brice A., Lozano, Tania M., Rahi, Russel K., and Krzmarzick, Mark J.
- Subjects
- *
TRICLOSAN , *TRICLOCARBAN , *ANAEROBIC digestion , *DEHALOGENATION , *SEWAGE - Abstract
Organohalide contaminants such as triclosan and triclocarban have been well documented in municipal wastewater treatment plants (WWTPs), but the degradation of these contaminants is not well understood. One possible removal mechanism is organohalide respiration by which bacteria reduce the halogenated compound. The purpose of this study was to determine the abundance of organohalide-respiring bacteria in eight WWTP anaerobic digesters. The obligate organohalide respiring Dehalococcoides mccartyi was the most abundant and averaged 3.3 × 107 copies of 16S rRNA genes per gram, while the Dehalobacter was much lower at 2.6 × 104 copies of 16S rRNA genes per gram. The genus Sulfurospirillum spp. was also detected at 1.0 × 107 copies of 16S rRNA genes per gram. No other known or putatively organohalide-respiring strains in the Dehalococcoidaceae family were found to be present nor were the genera Desulfitobacterium or Desulfomonile. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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39. GeneCARD-FISH: Detection of tceA and vcrA reductive dehalogenase genes in Dehalococcoides mccartyi by fluorescence in situ hybridization.
- Author
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Matturro, B. and Rossetti, S.
- Subjects
- *
HUMAN genes , *GENETIC databases , *TRICHLOROETHANE , *VINYL chloride , *DEHALOGENASES , *BACTERIAL genes , *DEHALOCOCCOIDES , *FLUORESCENCE in situ hybridization - Abstract
Due to the direct involvement in the biodegradation of chlorinated solvents, reductive dehalogenase genes (RDase) are considered biomarkers of the metabolic potential of different strains of Dehalococcoides mccartyi ( Dhc ). This is known to be the only microbe able to completely reduce toxic chlorinated solvents to harmless ethene. In the last years, several Molecular Biological Tools (MBTs) have been developed to optimize the detectability of Dhc cells and/or the RDase genes, with particular attention to the most important indicators of ethene formation, namely tceA and vcrA genes. Despite qPCR has been indicated as the MBT of choice, the use of CARD-FISH recently demonstrated to provide a more accurate quantification of Dhc cells in a wide concentration range, overcoming the drawbacks of loosing nucleic acids during the preparation of the sample associated with qPCR. CARD-FISH assays usually target 16S rRNA and up to date no protocol able to discriminate different Dhc strains by detecting RDase genes has been developed. This study reports the first evidence of in situ detection of tceA and vcrA genes into Dhc cells by applying a new procedure named geneCARD-FISH. Dhc strains carrying tceA and vcrA genes were identified and quantified in a PCE-to-ethene dechlorinating microbial enrichment and overall they represented 58.63% ± 2.45% and 40.46% ± 1.86% of the total Dhc cells, respectively. These values were markedly higher than those obtained by qPCR, which strongly underestimated the actual concentration of vcrA gene (0.08% ± 0.01% of Dhc 16S rRNA gene copies). The assay was successfully applied also for the analysis of environmental samples and remarkably strengthens the biomonitoring activities at field scale by providing the specific in situ discrimination of Dhc cells carrying the key-RDase genes. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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40. Dehalococcoides mccartyi NIT01, a novel isolate, dechlorinates high concentrations of chloroethenes by expressing at least six different reductive dehalogenases
- Author
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Arata Katayama, Masaki Asai, Takumi Nishiuchi, Mohamed Ismaeil, Naoko Yoshida, and Toshiya Kusakabe
- Subjects
Dehalococcoides ,Hypochlorous acid ,Strain (chemistry) ,biology ,Vinyl Chloride ,Dehalococcoides mccartyi ,Chloroflexi ,16S ribosomal RNA ,biology.organism_classification ,Biochemistry ,Vinyl chloride ,Trichloroethylene ,chemistry.chemical_compound ,Biodegradation, Environmental ,chemistry ,RNA, Ribosomal, 16S ,Membrane fraction ,Gene ,General Environmental Science - Abstract
This study presents the isolation of a novel strain of Dehalococcoides mccartyi, NIT01, which can completely dechlorinate up to 4.0 mM of trichloroethene to ethene via 1,2-cis-dichroroethene and vinyl chloride within 25 days. Strain NIT01 dechlorinated chloroethenes (CEs) at a temperature range of 25–32 °C and pH range of 6.5–7.8. The activity of the strain was inhibited by salt at more than 1.3% and inactivated by 1 h exposure to 2.0% air or 0.5 ppm hypochlorous acid. The genome of NIT01 was highly similar to that of the Dehalococcoides strains DCMB5, GT, 11a5, CBDB1, and CG5, and all included identical 16S rRNA genes. Moreover, NIT01 had 19 rdhA genes including NIT01-rdhA7 and rdhA13, which are almost identical to vcrA and pceA that encode known dehalogenases for tetrachloroethene and vinyl chloride, respectively. We also extracted RdhAs from the membrane fraction of NIT01 using 0.5% n-dodecyl-β- d -maltoside and separated them by anion exchange chromatography to identify those involved in CE dechlorination. LC/MS identification of the LDS-PAGE bands and RdhA activities in the fractions indicated cellular expression of six RdhAs. NIT01-RdhA7 (VcrA) and NIT01-RdhA15 were highly detected and NIT01-RdhA6 was the third-most detected. Among these three RdhAs, NIT01-RdhA15 and NIT01-RdhA6 had no biochemically identified relatives and were suggested to be novel functional dehalogenases for CEs. The expression of multiple dehalogenases may support bacterial tolerance to high concentrations of CEs. more...
- Published
- 2022
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41. Changes of the Proteome and Acetylome during Transition into the Stationary Phase in the Organohalide-Respiring
- Author
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Ute Lechner, Franziska Greiner-Haas, Dominique Türkowsky, Martin von Bergen, and Gary Sawers
- Subjects
Microbiology (medical) ,Anaerobic respiration ,proteome ,organohalide respiration ,Dehalococcoides mccartyi ,Microbiology ,Article ,03 medical and health sciences ,anaerobic respiration ,Virology ,Electrochemical gradient ,lcsh:QH301-705.5 ,mass spectrometry ,030304 developmental biology ,chemistry.chemical_classification ,0303 health sciences ,biology ,030306 microbiology ,Electron acceptor ,biology.organism_classification ,Enzyme ,lcsh:Biology (General) ,chemistry ,Biochemistry ,Membrane protein ,Acetylation ,Proteome ,chlorobenzene ,Tat transport ,growth phase ,Nε-lysine acetylation ,reductive dehalogenation ,Bacteria - Abstract
The strictly anaerobic bactGIerium Dehalococcoides mccartyi obligatorily depends on organohalide respiration for energy conservation and growth. The bacterium also plays an important role in bioremediation. Since there is no guarantee of a continuous supply of halogenated substrates in its natural environment, the question arises of how D. mccartyi maintains the synthesis and activity of dehalogenating enzymes under these conditions. Acetylation is a means by which energy-restricted microorganisms can modulate and maintain protein levels and their functionality. Here, we analyzed the proteome and Nε-lysine acetylome of D. mccartyi strain CBDB1 during growth with 1,2,3-trichlorobenzene as an electron acceptor. The high abundance of the membrane-localized organohalide respiration complex, consisting of the reductive dehalogenases CbrA and CbdbA80, the uptake hydrogenase HupLS, and the organohalide respiration-associated molybdoenzyme OmeA, was shown throughout growth. In addition, the number of acetylated proteins increased from 5% to 11% during the transition from the exponential to the stationary phase. Acetylation of the key proteins of central acetate metabolism and of CbrA, CbdbA80, and TatA, a component of the twin-arginine translocation machinery, suggests that acetylation might contribute to maintenance of the organohalide-respiring capacity of the bacterium during the stationary phase, thus providing a means of ensuring membrane protein integrity and a proton gradient. more...
- Published
- 2021
42. A microcosm treatability study for evaluating wood mulch-based amendments as electron donors for trichloroethene (Tce) reductive dechlorination
- Author
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Alessandro Battaglia, Alessandro Milani, Carolina Cruz Viggi, Marco Resitano, Simona Rossetti, Maria Letizia Di Franca, Matteo Tucci, Anna Legnani, Camilla de Laurentiis, Luca Ferioli, Edoardo Masut, Bruna Matturro, and Federico Aulenta more...
- Subjects
0301 basic medicine ,Iron filings ,Environmental remediation ,Geography, Planning and Development ,Electron donor ,010501 environmental sciences ,Aquatic Science ,Dehalococcoides mccartyi ,01 natural sciences ,Biochemistry ,complex mixtures ,reductive dechlorination ,Vinyl chloride ,03 medical and health sciences ,chemistry.chemical_compound ,wood mulch ,Bioremediation ,Reductive dechlorination ,TD201-500 ,0105 earth and related environmental sciences ,Water Science and Technology ,Water supply for domestic and industrial purposes ,microcosm study ,Hydraulic engineering ,dehalococcoides mccartyi ,trichloroethene ,030104 developmental biology ,chemistry ,iron filings ,Environmental chemistry ,Environmental science ,groundwater bioremediation ,Microcosm ,TC1-978 ,Mulch - Abstract
In this study, wood mulch-based amendments were tested in a bench-scale microcosm experiment in order to assess the treatability of saturated soils and groundwater from an industrial site contaminated by chlorinated ethenes. Wood mulch was tested alone as the only electron donor in order to assess its potential for stimulating the biological reductive dechlorination. It was also tested in combination with millimetric iron filings in order to assess the ability of the additive to accelerate/improve the bioremediation process. The efficacy of the selected amendments was compared with that of unamended control microcosms. The results demonstrated that wood mulch is an effective natural and low-cost electron donor to stimulate the complete reductive dechlorination of chlorinated solvents to ethene. Being a side-product of the wood industry, mulch can be used in environmental remediation, an approach which perfectly fits the principles of circular economy and addresses the compelling needs of a sustainable and low environmental impact remediation. The efficacy of mulch was further improved by the co-presence of iron filings, which accelerated the conversion of vinyl chloride into the ethene by increasing the H2 availability rather than by catalyzing the direct abiotic dechlorination of contaminants. Chemical analyses were corroborated by biomolecular assays, which confirmed the stimulatory effect of the selected amendments on the abundance of Dehalococcoides mccartyi and related reductive dehalogenase genes. Overall, this paper further highlights the application potential and environmental sustainability of wood mulch-based amendments as low-cost electron donors for the biological treatment of chlorinated ethenes. more...
- Published
- 2021
43. Metagenomic analysis reveals microbial interactions at the biocathode of a bioelectrochemical system capable of simultaneous trichloroethylene and cr(vi) reduction
- Author
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Simona Rossetti, Bruna Matturro, Marco Zepilli, Agnese Lai, and Mauro Majone
- Subjects
Microbiology (medical) ,bioelectrochemical remediation ,Cobalamin biosynthesis ,Trichloroethylene ,Chemistry ,Methanogenesis ,Microorganism ,Biofilm ,reductive dechlorination ,cr (VI) reduction, bioelectrochemical systems ,bioremediation ,Methanobrevibacter arboriphilus ,Microbial consortium ,Microbiology ,QR1-502 ,chemistry.chemical_compound ,Bioremediation ,Cr(VI) reduction ,Environmental chemistry ,Reductive dechlorination ,Methanobacterium formicicum ,Dehalococcoides mccartyi ,cr (VI) reduction ,bioelectrochemical systems ,Original Research - Abstract
Bioelectrochemical systems (BES) are attractive and versatile options for the bioremediation of organic or inorganic pollutants, including trichloroethylene (TCE) and Cr(VI), often found as co-contaminants in the environment. The elucidation of the microbial players’ role in the bioelectroremediation processes for treating multicontaminated groundwater is still a research need that attracts scientific interest. In this study, 16S rRNA gene amplicon sequencing and whole shotgun metagenomics revealed the leading microbial players and the primary metabolic interactions occurring in the biofilm growing at the biocathode where TCE reductive dechlorination (RD), hydrogenotrophic methanogenesis, and Cr(VI) reduction occurred. The presence of Cr(VI) did not negatively affect the TCE degradation, as evidenced by the RD rates estimated during the reactor operation with TCE (111±2 μeq/Ld) and TCE/Cr(VI) (146±2 μeq/Ld). Accordingly, Dehalococcoides mccartyi, the primary biomarker of the RD process, was found on the biocathode treating both TCE (7.82E+04±2.9E+04 16S rRNA gene copies g−1 graphite) and TCE/Cr(VI) (3.2E+07±2.37E+0716S rRNA gene copies g−1 graphite) contamination. The metagenomic analysis revealed a selected microbial consortium on the TCE/Cr(VI) biocathode. D. mccartyi was the sole dechlorinating microbe with H2 uptake as the only electron supply mechanism, suggesting that electroactivity is not a property of this microorganism. Methanobrevibacter arboriphilus and Methanobacterium formicicum also colonized the biocathode as H2 consumers for the CH4 production and cofactor suppliers for D. mccartyi cobalamin biosynthesis. Interestingly, M. formicicum also harbors gene complexes involved in the Cr(VI) reduction through extracellular and intracellular mechanisms. more...
- Published
- 2021
44. Evaluation of solid polymeric organic materials for use in bioreactive sediment capping to stimulate the degradation of chlorinated aliphatic hydrocarbons.
- Author
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Atashgahi, Siavash, Maphosa, Farai, Vrieze, Jo, Haest, Pieter, Boon, Nico, Smidt, Hauke, Springael, Dirk, and Dejonghe, Winnie
- Subjects
- *
SEDIMENT capping , *IN situ bioremediation , *VINYL chloride , *FERMENTATION , *DECHLORINATION (Chemistry) , *DEHALOCOCCOIDES - Abstract
In situ bioreactive capping is a promising technology for mitigation of surface water contamination by discharging polluted groundwater. Organohalide respiration (OHR) of chlorinated ethenes in bioreactive caps can be stimulated through incorporation of solid polymeric organic materials (SPOMs) that provide a sustainable electron source for organohalide respiring bacteria. In this study, wood chips, hay, straw, tree bark and shrimp waste, were assessed for their long term applicability as an electron donor for OHR of cis-dichloroethene (cDCE) and vinyl chloride (VC) in sediment microcosms. The initial release of fermentation products, such as acetate, propionate and butyrate led to the onset of extensive methane production especially in microcosms amended with shrimp waste, straw and hay, while no considerable stimulation of VC dechlorination was obtained in any of the SPOM amended microcosms. However, in the longer term, short chain fatty acids accumulation decreased as well as methanogenesis, whereas high dechlorination rates of VC and cDCE were established with concomitant increase of Dehalococcoides mccartyi and vcrA and bvcA gene numbers both in the sediment and on the SPOMs. A numeric simulation indicated that a capping layer of 40 cm with hay, straw, tree bark or shrimp waste is suffice to reduce the groundwater VC concentration below the threshold level of 5 μg/l before discharging into the Zenne River, Belgium. Of all SPOMs, the persistent colonization of tree bark by D. mccartyi combined with the lowest stimulation of methanogenesis singled out tree bark as a long-term electron donor for OHR of cDCE/VC in bioreactive caps. [ABSTRACT FROM AUTHOR] more...
- Published
- 2014
- Full Text
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45. Kinetics of dechlorination by Dehalococcoides mccartyi using different carbon sources.
- Author
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Schneidewind, Uwe, Haest, Pieter Jan, Atashgahi, Siavash, Maphosa, Farai, Hamonts, Kelly, Maesen, Miranda, Calderer, Montse, Seuntjens, Piet, Smidt, Hauke, Springael, Dirk, and Dejonghe, Winnie
- Subjects
- *
DECHLORINATION (Chemistry) , *DEHALOCOCCOIDES , *CARBON , *ANAEROBIC digestion , *STREAM chemistry , *WATER pollution - Abstract
Abstract: Stimulated anaerobic dechlorination is generally considered a valuable step for the remediation of aquifers polluted with chlorinated ethenes (CEs). Correct simulation and prediction of this process in situ, however, require good knowledge of the associated biological reactions. The aim of this study was to evaluate the dechlorination reaction in an aquifer contaminated with trichloroethene (TCE) and its daughter products, discharging into the Zenne River. Different carbon sources were used in batch cultures and these were related to the dechlorination reaction, together with the monitored biomarkers. Appropriate kinetic formulations were assessed. Reductive dechlorination of TCE took place only when external carbon sources were added to microcosms, and occurred concomitant with a pronounced increase in the Dehalococcoides mccartyi cell count as determined by 16S rRNA gene-targeted qPCR. This indicates that native dechlorinating bacteria are present in the aquifer of the Zenne site and that the oligotrophic nature of the aquifer prevents a complete degradation to ethene. The type of carbon source, the cell number of D. mccartyi or the reductive dehalogenase genes, however, did not unequivocally explain the observed differences in degradation rates or the extent of dechlorination. Neither first-order, Michaelis–Menten nor Monod kinetics could perfectly simulate the dechlorination reactions in TCE spiked microcosms. A sensitivity analysis indicated that the inclusion of donor limitation would not significantly enhance the simulations without a clear process understanding. Results point to the role of the supporting microbial community but it remains to be verified how the complexity of the microbial (inter)actions should be represented in a model framework. [Copyright &y& Elsevier] more...
- Published
- 2014
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46. Inferring community dynamics of organohalide-respiring bacteria in chemostats by covariance of rdhA gene abundance.
- Author
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Marshall, Ian P.G., Azizian, Mohammad F., Semprini, Lewis, and Spormann, Alfred M.
- Subjects
- *
CHEMOSTAT , *GENE expression , *DEHALOGENASES , *TETRACHLOROETHYLENE , *ELECTRON donors , *DNA microarrays , *DEHALOCOCCOIDES - Abstract
We have developed a novel approach to identifying and quantifying closely related organohalide-respiring bacteria. Our approach made use of the unique genomic associations of specific reductive dehalogenase subunit A encoding genes ( rdhA) that exist in known strains of Dehalococcoides mccartyi and Desulfitobacterium and the distinguishing covariance pattern of observed rdhA genes to assign genes to unknown strains. To test this approach, we operated five anaerobic reductively dechlorinating chemostats for 3-4 years with tetrachloroethene and trichloroethene as terminal electron acceptors and lactate/formate as electron donors. The presence and abundance of rdhA genes were determined comprehensively at the community level using a custom-developed Reductive Dehalogenase Chip ( RDH Chip) DNA microarray and used to define putative strains of Dehalococcoides mccartyi and Desulfitobacterium sp. This monitoring revealed that stable chemical performance of chemostats was reflected by a stable community of reductively dechlorinating bacteria. However, perturbations introduced by, for example, electron donor limitation or addition of the competing electron acceptor sulfate led to overall changes in the chemostat performance, including incomplete reduction in the chloroethene substrates, and in the population composition of reductively dehalogenating bacteria. Interestingly, there was a high diversity of operationally defined D. mccartyi strains between the chemostats with almost all strains unique to their specific chemostats in spite of similar selective pressure and similar inocula shared between chemostats. [ABSTRACT FROM AUTHOR] more...
- Published
- 2014
- Full Text
- View/download PDF
47. Normalized Quantitative PCR Measurements as Predictors for Ethene Formation at Sites Impacted with Chlorinated Ethenes
- Author
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Frank E. Löffler, Dora Taggart, Janet K. Hatt, Robert W. Murdoch, Kirsti M. Ritalahti, Katherine Clark, and Brett R. Baldwin
- Subjects
DNA, Bacterial ,0301 basic medicine ,endocrine system ,030106 microbiology ,Vinyl Chloride ,010501 environmental sciences ,01 natural sciences ,Article ,Vinyl chloride ,03 medical and health sciences ,chemistry.chemical_compound ,RNA, Ribosomal, 16S ,Environmental Chemistry ,Gene ,0105 earth and related environmental sciences ,Dehalogenase ,Chemistry ,Dehalococcoides mccartyi ,Chloroflexi ,General Chemistry ,Ethylenes ,Ribosomal RNA ,16S ribosomal RNA ,Molecular biology ,Biodegradation, Environmental ,Real-time polymerase chain reaction ,Bacterial 16S rRNA - Abstract
Quantitative PCR (qPCR) targeting Dehalococcoides mccartyi (Dhc) biomarker genes supports effective management at sites impacted with chlorinated ethenes. To establish correlations between Dhc biomarker gene abundances and ethene formation (i.e., detoxification), 859 groundwater samples representing 62 sites undergoing monitored natural attenuation or enhanced remediation were analyzed. Dhc 16S rRNA genes and the vinyl chloride (VC) reductive dehalogenase genes bvcA and vcrA were detected in 88% and 61% of samples, respectively, from wells with ethene. Dhc 16S rRNA, bvcA, vcrA, and tceA (implicated in cometabolic reductive VC dechlorination) gene abundances all positively correlated with ethene formation. Significantly greater ethene concentrations were observed when Dhc 16S rRNA gene and VC RDase gene abundances exceeded 10(7) and 10(6) copies L(−1), respectively, and when Dhc 16S rRNA- and bvcA + vcrA-to-total bacterial 16S rRNA gene ratios exceeded 0.1%. Dhc 16S rRNA gene-to-vcrA/bvcA ratios near unity also indicated elevated ethene; however, no increased ethene was observed in 19 wells where vcrA and/or bvcA gene copy numbers exceeded Dhc cell numbers 10- to 10 000-fold. Approximately one-third of samples with detectable ethene lacked bvcA, vcrA, and tceA, suggesting that comprehensive understanding of VC detoxification biomarkers has not been achieved. Although the current biomarker suite is incomplete, the data analysis corroborates the value of the available Dhc DNA biomarkers for prognostic and diagnostic groundwater monitoring at sites impacted with chlorinated ethenes. more...
- Published
- 2018
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48. Long-term dechlorination of cis-DCE to ethene with co-immobilized Dehalococcoides mccartyi BAV1 and Clostridium butyricum in silica gel system.
- Author
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Lu, Che-Wei, Kao, Chih-Ming, Le, Nhu Nguyet, Lin, Chu-Ching, and Chen, Ssu-Ching
- Subjects
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CLOSTRIDIUM butyricum , *SILICA gel , *ANAEROBIC bacteria , *VINYL chloride , *POISONS , *CLOSTRIDIUM perfringens , *CLOSTRIDIUM acetobutylicum - Abstract
Chloroethenes are common groundwater pollutants, and have been classified as toxic and carcinogenic to humans. The metabolites of chloroethenes, cis -dichloroethene (cis -DCE) and vinyl chloride (VC) commonly accumulate in groundwater due to their recalcitrant reductive dechlorination under anaerobic conditions. Dehalococcoides mccartyi (Dhc) is the key anaerobic bacteria for complete dechlorination of chloroethene, and Clostridium butyricum (C. butyricum) can provide hydrogen for supporting the growth of Dhc. In this study, we co-immobilized Dhc strain BAV1 and C. butyricum in a silica gel to determine the ability of the complete dechlorination of cis -DCE. Our results showed that our immobilized system could protect BAV1 from a high concentration (8 mM) of cis -DCE to carry out complete dechlorination. After the long-term use of our immobilized system, the activity of complete dechlorination was maintained for more than 180 consecutive days. Furthermore, we applied the immobilized system to remediate contaminated groundwater and uncovered the complete dechlorination of cis -DCE into ethene, a non-toxic product, within 28 days. Therefore, this novel co-immobilized system could serve a solution for bioremediation at chloroethene-contaminated sites. [Display omitted] • Immobilized Dehalococcoides mccartyi BAV1 and Clostridium butyricum for the complete dechlorination was first set up. • Long-term dechlorination of co-immobilized BAV1 and C. butyricum in silica gel was demonstrated. • Our immobilized system can be reused for many cycles during the operation time of more than 180 consecutive days. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
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49. Quantitative estimation of Dehalococcoides mccartyi at laboratory and field scale: Comparative study between CARD-FISH and Real Time PCR.
- Author
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Matturro, B., Heavner, G.L., Richardson, R.E., and Rossetti, S.
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DEHALOCOCCOIDES , *POLYMERASE chain reaction , *MICROBIOLOGICAL techniques , *BACTERIAL typing , *BIOREMEDIATION , *NATURAL attenuation of hazardous wastes , *RIBOSOMAL RNA , *COMPARATIVE studies - Abstract
Abstract: Dehalococcoides mccartyi detectability in the field is a fundamental tool to assess the efficiency of natural attenuation or engineered bioremediation in chlorinated solvent-contaminated sites. This study reports on the direct comparison of quantitative data obtained by Real Time PCR (qPCR) and CAtalyzed Reporter Deposition-Fluorescence In situ Hybridization (CARD-FISH) over a wide range of Dehalococcoides concentrations (10–108 cellsmL−1) both in three independent 10-fold serial dilutions of a laboratory dechlorinating enrichment and in 49 groundwater samples from 6 different contaminated sites. Dehalococcoides enumeration by CARD-FISH yielded a linear curve in the analyzed concentration range which was consistent with the expected concentrations and showed good reproducibility in triplicate assays. Alternatively, qPCR did not allow for the discrimination of 16S rRNA gene concentrations lower than 103 gene copiesmL−1 either in the dechlorinating mixed culture or in field samples. Overall this study highlights the limits of qPCR quantification, especially in samples where low concentrations of this microorganism may be expected, and suggests the use of a confirmatory methodology under these particular conditions. [Copyright &y& Elsevier] more...
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- 2013
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50. Debromination of TetraBromoBisphenol-A (TBBPA) depicting the metabolic versatility of Dehalococcoides
- Author
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Siyan Zhao, Sungwoo Bae, Rajaganesan Ramaswamy, and Jianzhong He
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Proteomics ,Environmental Engineering ,Health, Toxicology and Mutagenesis ,Polybrominated Biphenyls ,0211 other engineering and technologies ,02 engineering and technology ,010501 environmental sciences ,01 natural sciences ,chemistry.chemical_compound ,Bioremediation ,Environmental Chemistry ,Waste Management and Disposal ,Flame Retardants ,0105 earth and related environmental sciences ,Dehalogenase ,Dehalococcoides ,chemistry.chemical_classification ,021110 strategic, defence & security studies ,biology ,Dehalococcoides mccartyi ,Halogenation ,Electron acceptor ,biology.organism_classification ,Pollution ,Biodegradation, Environmental ,chemistry ,Environmental chemistry ,Brominated flame retardant ,Tetrabromobisphenol A - Abstract
TetraBromoBisphenol-A (TBBPA) is a widely used brominated flame retardant and an emerging contaminant that has amassed significant environmental impacts. Though there are a few studies that report the bioremediation of TBBPA, there is no direct evidence to suggest a metabolic use of TBBPA as the sole electron acceptor, which offers an advantage in the complete and energy-efficient process of debromination under anaerobic conditions. In this study, Dehalococcoides mccartyi strain CG1 was identified to be capable of utilizing TBBPA as the sole electron acceptor at its maximum soluble concentrations (7.3 μM) coupled with cell growth. A previously characterized reductive dehalogenase (RDase), PcbA1, and six other RDases of strain CG1 were detected during TBBPA debromination via transcriptional and proteomic analyses. Furthermore, as a commonly co-contaminated brominated flame retardant of TBBPA, penta-BDEs were debrominated synchronously with TBBPA by strain CG1. This study provides deeper insights into the versatile dehalogenation capabilities of D. mccartyi strain CG1 and its role in in situ remediations of persistent organic pollutants in the environment. more...
- Published
- 2021
- Full Text
- View/download PDF
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