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Dehalococcoides

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https://www.readbyqxmd.com/read/29283566/interaction-mode-and-regioselectivity-in-vitamin-b12-dependent-dehalogenation-of-aryl-halides-by-dehalococcoides-mccartyi-strain-cbdb1
#1
Shangwei Zhang, Lorenz Adrian, Gerrit Schüürmann
The bacterium Dehalococcoides, strain CBDB1, transforms aromatic halides through reductive dehalogenation. So far, however, the structures of its vitamin B12-containing dehalogenases are unknown, hampering clarification of the catalytic mechanism and substrate specificity as basis for targeted remediation strategies. This study employs a quantum chemical donor-acceptor approach for the Co(I)-substrate electron transfer. Computational characterization of the substrate electron affinity at carbon-halogen bonds enables discriminating aromatic halides ready for dehalogenation by strain CBDB1 (active substrates) from non-dehalogenated (inactive) counterparts with 92% accuracy, covering 86 of 93 bromobenzenes, chlorobenzenes, chlorophenols, chloroanilines, polychlorinated biphenyls, and dibenzo-p-dioxins...
December 28, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29259088/homoacetogenesis-in-deep-sea-chloroflexi-as-inferred-by-single-cell-genomics-provides-a-link-to-reductive-dehalogenation-in-terrestrial-dehalococcoidetes
#2
Holly L Sewell, Anne-Kristin Kaster, Alfred M Spormann
The deep marine subsurface is one of the largest unexplored biospheres on Earth and is widely inhabited by members of the phylum Chloroflexi In this report, we investigated genomes of single cells obtained from deep-sea sediments of the Peruvian Margin, which are enriched in such Chloroflexi 16S rRNA gene sequence analysis placed two of these single-cell-derived genomes (DscP3 and Dsc4) in a clade of subphylum I Chloroflexi which were previously recovered from deep-sea sediment in the Okinawa Trough and a third (DscP2-2) as a member of the previously reported DscP2 population from Peruvian Margin site 1230...
December 19, 2017: MBio
https://www.readbyqxmd.com/read/29223901/thermally-enhanced-in-situ-bioremediation-of-groundwater-contaminated-with-chlorinated-solvents-a-field-test
#3
Jan Němeček, Jana Steinová, Roman Špánek, Tomáš Pluhař, Petr Pokorný, Petra Najmanová, Vladislav Knytl, Miroslav Černík
In situ bioremediation (ISB) using reductive dechlorination is a widely accepted but relatively slow approach compared to other technologies for the treatment of groundwater contaminated by chlorinated ethenes (CVOCs). Due to the known positive kinetic effect on microbial metabolism, thermal enhancement may be a viable means of accelerating ISB. We tested thermally enhanced ISB in aquifers situated in sandy saprolite and underlying fractured granite. The system comprised pumping, heating and subsequent injection of contaminated groundwater aiming at an aquifer temperature of 20-30°C...
December 7, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29195092/dechlorinating-performance-of-dehalococcoides-spp-mixed-culture-enhanced-by-tourmaline
#4
Wei Wang, Xingyu Liu, Kerui Li, Tielong Li
Dehalococcoides spp. were extensively studied and applied to in-situ trichloroethylene (TCE) remediation since it is the only genus that can reduce TCE to harmless ethene completely. However, this technology was hindered because of the requirement of electron donor (i.e. hydrogen or fermentable organic substrate). Considering the spontaneous electric field and in-situ hydrogen production capacity of tourmaline, this mineral was used as an environmental-friendly bio-promoter for dechlorinating mixed culture containing Dehalococcoides spp...
November 20, 2017: Chemosphere
https://www.readbyqxmd.com/read/29178800/natural-attenuation-and-anaerobic-benzene-detoxification-processes-at-a-chlorobenzene-contaminated-industrial-site-inferred-from-field-investigations-and-microcosm-studies
#5
Wenjing Qiao, Fei Luo, Line Lomheim, Elizabeth Erin Mack, Shujun Ye, Jichun Wu, Elizabeth A Edwards
A five-year site investigation was conducted at a former chemical plant in Nanjing, China. The main contaminants were 1,2,4-trichlorobenzene (TCB) reaching concentrations up to 7300 µg/L, dichlorobenzene (DCB) isomers, monochlorobenzene (MCB) and benzene. Over time, these contaminants naturally attenuated to below regulatory levels under anaerobic conditions. To confirm the transformation processes and to explore the mechanisms, a corresponding laboratory microcosm study was completed demonstrating that 1,2,4-TCB was dechlorinated to 1,2-DCB, 1,3-DCB and 1,4-DCB in approximately 2%/10%/88% molar proportions...
November 27, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/29112726/reconstructed-genomes-of-novel-dehalococcoides-mccartyi-strains-from-1-2-3-4-tetrachlorodibenzo-p-dioxin-dechlorinating-enrichment-cultures-reveal-divergent-reductive-dehalogenase-gene-profiles
#6
Hang T Dam, John Vollmers, Anne-Kristin Kaster, Max M Häggblom
Polychlorinated dibenzo-p-dioxin (PCDD) contaminated sites are widespread and associated with a variety of anthropogenic sources. PCDDs and other organohalide pollutants can serve as terminal electron acceptors for anaerobic respiration by specialized bacteria containing reductive dehalogenases (RdhA). These microorganisms, therefore, play an important role in bioremediation of PCDD contaminated sites. Two anaerobic enrichment cultures established using sediments collected from the PCDD polluted Hackensack (USA) and Kymijoki (Finland) rivers showed robust reductive dechlorination of 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TeCDD)...
November 3, 2017: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/29069488/triple-element-compound-specific-stable-isotope-analysis-of-1-2-dichloroethane-for-characterization-of-the-underlying-dehalogenation-reaction-in-two-dehalococcoides-mccartyi-strains
#7
Steffi Franke, Christina Lihl, Julian Renpenning, Martin Elsner, Ivonne Nijenhuis
Chlorinated ethanes belong to the most common groundwater and soil contaminants. Of these, 1,2-dichloroethane (1,2-DCA) is an man-made, persistent and toxic contaminant, released due to improper waste treatment at versatile production sites. This study investigated the anaerobic transformation of 1,2-DCA by Dehalococcoides mccartyi strain 195 and strain BTF08 using triple-element compound-specific stable isotope analysis (CSIA) of carbon, chlorine and hydrogen for the first time. Isotope fractionation patterns for carbon (ε C BTF08   =   -28...
October 22, 2017: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/29040515/resilience-and-recovery-of-dehalococcoides-mccartyi-following-low-ph-exposure
#8
Yi Yang, Natalie L Cápiro, Jun Yan, Tyler F Marcet, Kurt D Pennell, Frank E Löffler
Bioremediation treatment (e.g. biostimulation) can decrease groundwater pH with consequences for Dehalococcoides mccartyi (Dhc) reductive dechlorination activity. To explore the pH resilience of Dhc, the Dhc-containing consortium BDI was exposed to pH 5.5 for up to 40 days. Following 8- and 16-day exposure periods to pH 5.5, dechlorination activity and growth recovered when returned to pH 7.2; however, the ability of the culture to dechlorinate vinyl chloride (VC) to ethene was impaired (i.e. decreased rate of VC transformation)...
December 1, 2017: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/29040506/high-throughput-sequencing-revealed-novel-dehalococcoidia-in-dechlorinating-microbial-enrichments-from-pcb-contaminated-marine-sediments
#9
Bruna Matturro, Emanuela Frascadore, Simona Rossetti
In this study, six PCE-to-ethene dechlorinating cultures, fed with a fermentable substrate (lactate) or hydrogen as electron donor, were obtained from PCB and PCE dechlorinating microcosms constructed with PCB-contaminated marine sediments. A novel Chloroflexi member (OTU-DIS1) affiliated to Dehalococcoidales Incertae Sedis, only distantly related to known dechlorinating bacteria, dominated the enrichment cultures (up to 86% of total OTUs). Sulfate-, thiosulfate- and sulfur-reducing bacteria affiliated to genera Desulfobacter, Dethiosulfatibacter and Desulfuromusa were also found to lesser extent...
November 1, 2017: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/29040474/co-occurrence-of-genes-for-aerobic-and-anaerobic-biodegradation-of-dichloroethane-in-organochlorine-contaminated-groundwater
#10
Jacob E Munro, Önder Kimyon, Deborah J Rich, Joanna Koenig, Sihui Tang, Adrian Low, Matthew Lee, Mike Manefield, Nicholas V Coleman
1,2-Dichloroethane (DCA) is a problematic groundwater pollutant. Factors influencing the distribution and activities of DCA-degrading bacteria are not well understood, which has hampered their application for bioremediation. Here, we used quantitative PCR to investigate the distribution of putative DCA-dehalogenating bacteria at a DCA-impacted site in Sydney (Australia). The dehalogenase genes dhlA, tceA and bvcA were detected in all groundwater samples (n = 15), while vcrA was found in 11/15 samples. The 16S rRNA gene sequences specific to the dehalogenating genera Dehalobacter, Desulfitobacterium and Dehalogenimonas were detected in 15/15, 13/15 and 13/15 samples, respectively, while Dehalococcoides sequences were found in 9/15 samples...
November 1, 2017: FEMS Microbiology Ecology
https://www.readbyqxmd.com/read/29031631/most-probable-number-with-visual-based-lamp-for-the-quantification-of-reductive-dehalogenase-genes-in-groundwater-samples
#11
Yogendra H Kanitkar, Robert D Stedtfeld, Paul B Hatzinger, Syed A Hashsham, Alison M Cupples
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)...
October 12, 2017: Journal of Microbiological Methods
https://www.readbyqxmd.com/read/28943350/spatial-distribution-and-diversity-of-organohalide-respiring-bacteria-and-their-relationships-with-polybrominated-diphenyl-ether-concentration-in-taihu-lake-sediments
#12
Juan Chen, Pei-Fang Wang, Chao Wang, Jia-Jia Liu, Han Gao, Xun Wang
It is acknowledged that organohalide-respiring bacteria (OHRB) can degrade polybrominated diphenyl ethers (PBDEs); however, very little is known about the distribution of OHRB or their response to PBDE contamination in natural sediments. We collected sediments from 28 sampling sites in Taihu Lake, China, and investigated the spatial distribution and diversity of OHRB, and the relationships between the PBDE contamination levels and the PBDE removal potential. The abundances of five typical OHRB genera, namely Dehalobacter, Dehalococcoides, Dehalogenimonas, Desulfitobacterium, and Geobacter, ranged from 0...
September 21, 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28919889/dehalococcoides-as-a-potential-biomarker-evidence-for-uncharacterized-organohalides-in-environmental-samples
#13
Qihong Lu, Ling Yu, Zhiwei Liang, Qingyun Yan, Zhili He, Tiangang Luan, Dawei Liang, Shanquan Wang
The massive production and improper disposal of organohalides resulted in worldwide contamination in soil and water. However, their environmental survey based on chromatographic methods was hindered by challenges in testing the extremely wide variety of organohalides. Dehalococcoides as obligate organohalide-respiring bacteria exclusively use organohalides as electron acceptors to support their growth, of which the presence could be coupled with organohalides and, therefore, could be employed as a biomarker of the organohalide pollution...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28914537/coupling-bioflocculation-of-dehalococcoides-mccartyi-to-high-rate-reductive-dehalogenation-of-chlorinated-ethenes
#14
Anca G Delgado, Devyn Fajardo-Williams, Emily Bondank, Sofia Esquivel-Elizondo, Rosa Krajmalnik-Brown
Continuous bioreactors operated at low hydraulic retention times have rarely been explored for reductive dehalogenation of chlorinated ethenes. The inability to consistently develop such bioreactors affects the way growth approaches for Dehalococcoides mccartyi bioaugmentation cultures are envisioned. It also affects interpretation of results from in situ continuous treatment processes. We report bioreactor performance and dehalogenation kinetics of a D. mccartyi-containing consortium in an upflow bioreactor...
September 15, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28894752/identification-of-multiple-dehalogenase-genes-involved-in-tetrachloroethene-to-ethene-dechlorination-in-a-dehalococcoides-dominated-enrichment-culture
#15
Mohamed Ismaeil, Naoko Yoshida, Arata Katayama
Chloroethenes (CEs) are widespread groundwater toxicants that are reductively dechlorinated to nontoxic ethene (ETH) by members of Dehalococcoides. This study established a Dehalococcoides-dominated enrichment culture (designated "YN3") that dechlorinates tetrachloroethene (PCE) to ETH with high dechlorination activity, that is, complete dechlorination of 800 μM PCE to ETH within 14 days in the presence of Dehalococcoides species at 5.7 ± 1.9 × 10(7) copies of 16S rRNA gene/mL. The metagenome of YN3 harbored 18 rdhA genes (designated YN3rdhA1-18) encoding the catalytic subunit of reductive dehalogenase (RdhA), four of which were suggested to be involved in PCE-to-ETH dechlorination based on significant increases in their transcription in response to CE addition...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28843895/dechlorinating-bacteria-are-abundant-but-anaerobic-dechlorination-of-weathered-polychlorinated-dibenzo-p-dioxins-and-dibenzofurans-in-contaminated-sediments-is-limited
#16
Sanna Mäntynen, Anna-Lea Rantalainen, Max M Häggblom
The potential for microbial dechlorination of the weathered polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was determined in sediments with historical contamination by the chlorophenol wood preservative Ky-5 and its associated dimeric impurities. Sediments were collected from four sites of the Kymijoki River in South-Eastern Finland located at 0, 20, 30, and 60 km downstream from the source of contamination, and at a reference site. We examined the congener profiles of historical PCDD/Fs, including non-2,3,7,8-substituted congeners, and determined the dechlorination potential in sediments at the different sites of the river...
December 2017: Environmental Pollution
https://www.readbyqxmd.com/read/28809851/grape-pomace-compost-harbors-organohalide-respiring-dehalogenimonas-species-with-novel-reductive-dehalogenase-genes
#17
Yi Yang, Steven A Higgins, Jun Yan, Burcu Şimşir, Karuna Chourey, Ramsunder Iyer, Robert L Hettich, Brett Baldwin, Dora M Ogles, Frank E Löffler
Organohalide-respiring bacteria have key roles in the natural chlorine cycle; however, most of the current knowledge is based on cultures from contaminated environments. We demonstrate that grape pomace compost without prior exposure to chlorinated solvents harbors a Dehalogenimonas (Dhgm) species capable of using chlorinated ethenes, including the human carcinogen and common groundwater pollutant vinyl chloride (VC) as electron acceptors. Grape pomace microcosms and derived solid-free enrichment cultures were able to dechlorinate trichloroethene (TCE) to less chlorinated daughter products including ethene...
August 15, 2017: ISME Journal
https://www.readbyqxmd.com/read/28803405/pcb-dechlorination-hotspots-and-reductive-dehalogenase-genes-in-sediments-from-a-contaminated-wastewater-lagoon
#18
Timothy E Mattes, Jessica M Ewald, Yi Liang, Andres Martinez, Andrew Awad, Patrick Richards, Keri C Hornbuckle, Jerald L Schnoor
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...
August 12, 2017: Environmental Science and Pollution Research International
https://www.readbyqxmd.com/read/28777963/biochar-accelerates-microbial-reductive-debromination-of-2-2-4-4-tetrabromodiphenyl-ether-bde-47-in-anaerobic-mangrove-sediments
#19
Juan Chen, Chao Wang, Ying Pan, Shazia Shyla Farzana, Nora Fung-Yee Tam
A common congener of polybrominated diphenyl ethers, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), is a prevalent, persistent and toxic pollutant. It could be removed by reduction debromination by microorganisms but the rate is often slow. The study hypothesized that spent mushroom substrate derived biochar amendment could accelerate the microbial reductive debromination of BDE-47 in anaerobic mangrove sediment slurries and evaluated the mechanisms behind. At the end of 20-week experiment, percentages of residual BDE-47 in slurries amended with biochar were significantly lower but debromination products were higher than those without biochar...
July 28, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28764859/modeling-3d-csia-data-carbon-chlorine-and-hydrogen-isotope-fractionation-during-reductive-dechlorination-of-tce-to-ethene
#20
Boris M Van Breukelen, Héloïse A A Thouement, Philip E Stack, Mindy Vanderford, Paul Philp, Tomasz Kuder
Reactive transport modeling of multi-element, compound-specific isotope analysis (CSIA) data has great potential to quantify sequential microbial reductive dechlorination (SRD) and alternative pathways such as oxidation, in support of remediation of chlorinated solvents in groundwater. As a key step towards this goal, a model was developed that simulates simultaneous carbon, chlorine, and hydrogen isotope fractionation during SRD of trichloroethene, via cis-1,2-dichloroethene (and trans-DCE as minor pathway), and vinyl chloride to ethene, following Monod kinetics...
September 2017: Journal of Contaminant Hydrology
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