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Yue Lu, Javier Ramiro-Garcia, Pieter Vandermeeren, Steffi Herrmann, Danuta Cichocka, Dirk Springael, Siavash Atashgahi, Hauke Smidt
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...
December 1, 2016: Applied Microbiology and Biotechnology
Lucia Pierro, Bruna Matturro, Simona Rossetti, Marco Sagliaschi, Salvatore Sucato, Eduard Alesi, Ernst Bartsch, Firoozeh Arjmand, Marco Petrangeli Papini
A pilot-scale study aiming to evaluate the potential use of poly-3-hydroxy-butyrate (PHB) as an electron donor source for in situ bioremediation of chlorinated hydrocarbons in groundwater was conducted. Compared with commercially available electron donors, PHB offers a restricted fermentation pathway (i.e., through acetic acid and molecular hydrogen) by avoiding the formation of any residual carbon that could potentially spoil groundwater quality. The pilot study was carried out at an industrial site in Italy, heavily contaminated by different chlorinated aliphatic hydrocarbons (CAHs)...
November 27, 2016: New Biotechnology
Bryan R Crable, Jessica R Sieber, Xinwei Mao, Lisa Alvarez-Cohen, Robert Gunsalus, Rachel R Ogorzalek Loo, Hong Nguyen, Michael J McInerney
Syntrophic butyrate metabolism involves the thermodynamically unfavorable production of hydrogen and/or formate from the high potential electron donor, butyryl-CoA. Such redox reactions can occur only with energy input by a process called reverse electron transfer. Previous studies have demonstrated that hydrogen production from butyrate requires the presence of a proton gradient, but the biochemical machinery involved has not been clearly elucidated. In this study, the gene and enzyme systems involved in reverse electron transfer by Syntrophomonas wolfei were investigated using proteomic and gene expression approaches...
2016: Frontiers in Microbiology
Siyan Zhao, Chang Ding, Jianzhong He
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 1,461,973 base-pair chromosome, strain 11a5 distinguishes itself from other D. mccartyi strains by possessing a 5,940 base-pair circular extrachromosomal genetic element which contains a reductive dehalogenase homolog. The whole genome of strain 11a5 harbors 31 putative reductive dehalogenase genes...
November 16, 2016: FEMS Microbiology Ecology
Anne-Sophie Charlotte Hieke, Robin Brinkmeyer, Kevin M Yeager, Kimberly Schindler, Saijin Zhang, Chen Xu, Patrick Louchouarn, Peter H Santschi
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...
November 14, 2016: Marine Biotechnology
Cresten B Mansfeldt, Gretchen W Heavner, Annette R Rowe, Boris Hayete, Bruce W Church, Ruth E Richardson
The interpretation of high-throughput gene expression data for non-model microorganisms remains obscured because of the high fraction of hypothetical genes and the limited number of methods for the robust inference of gene networks. Therefore, to elucidate gene-gene and gene-condition linkages in the bioremediation-important genus Dehalococcoides, we applied a Bayesian inference strategy called Reverse Engineering/Forward Simulation (REFS™) on transcriptomic data collected from two organohalide-respiring communities containing different Dehalococcoides mccartyi strains: the Cornell University mixed community D2 and the commercially available KB-1® bioaugmentation culture...
2016: PloS One
Hang T Dam, Max M Häggblom
Polychlorinated dibenzo-p-dioxins (PCDDs) are among the most persistent organic pollutants. Although the total input of PCDDs into the environment has decreased substantially over the past four decades, their input via non-point sources is still increasing, especially in estuarine metropolitan areas. Here we report on the microbially mediated reductive dechlorination of PCDDs in anaerobic enrichment cultures established from sediments collected from five locations along the Hackensack River, NJ and investigate the impacts of sediment physicochemical characteristics on dechlorination activity...
November 3, 2016: Chemosphere
Koshlan Mayer-Blackwell, Maeva Fincker, Olivia Molenda, Benjamin Callahan, Holly Sewell, Susan Holmes, Elizabeth A Edwards, Alfred M Spormann
Bioremediation of groundwater contaminated with chlorinated aliphatic hydrocarbons such as perchloroethene and trichloroethene can result in the accumulation of the undesirable intermediate vinyl chloride. Such accumulation can either be due to the absence of specific vinyl chloride respiring Dehalococcoides mccartyi or to the inhibition of such strains by the metabolism of other microorganisms. The fitness of vinyl chloride respiring Dehalococcoides mccartyi subpopulations is particularly uncertain in the presence of chloroethene/chloroethane cocontaminant mixtures, which are commonly found in contaminated groundwater...
November 3, 2016: Environmental Science & Technology
Yan Xu, Kelvin B Gregory, Jeanne M Vanbriesen
Biodegradation of polychlorinated biphenyls (PCBs) is an important transformation and detoxification route in the environment. To better understand the influence of PCB congener compositions on dechlorination, sediments from two rivers, Hudson and Grasse, and two PCB mixtures (PCB 5/12, 64/71, 105/114 and 149/153/170 in Mixture 1 and PCB 5/12, 64/71, 82/97/99, 144/170 in Mixture 2) were used for this microcosm study. The Grasse River sediment microcosms exhibited more extensive dechlorination than the Hudson River sediment microcosms...
October 27, 2016: Environmental Science & Technology
Robert D Stedtfeld, Tiffany M Stedtfeld, Farag Samhan, Yogendra H Kanitkar, Paul B Hatzinger, Alison M Cupples, Syed A Hashsham
Nucleic acid amplification of biomarkers is increasingly used to monitor microbial activity and assess remedial performance in contaminated aquifers. Previous studies described the use of filtration, elution, and direct isothermal amplification (i.e. no DNA extraction and purification) as a field-able means to quantify Dehalococcoides spp. in groundwater. This study expands previous work with direct loop mediated isothermal amplification (LAMP) for the detection and quantification of Dehalobacter spp. in groundwater...
October 5, 2016: Journal of Microbiological Methods
Bruna Matturro, Carla Ubaldi, Simona Rossetti
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...
2016: Frontiers in Microbiology
Siavash Atashgahi, Yue Lu, Ying Zheng, Edoardo Saccenti, Maria Suarez-Diez, Javier Ramiro-Garcia, Heinrich Eisenmann, Martin Elsner, Alfons J M Stams, Dirk Springael, Winnie Dejonghe, Hauke Smidt
Biostimulation is widely used to enhance reductive dechlorination of chlorinated ethenes in contaminated aquifers. However, the knowledge on corresponding biogeochemical responses is limited. In this study, glycerol was injected in an aquifer contaminated with cis-dichloroethene (cDCE), and geochemical and microbial shifts were followed for 265 days. Consistent with anoxic conditions and sulfate reduction after biostimulation, MiSeq 16S rRNA gene sequencing revealed temporarily increased relative abundance of Firmicutes, Bacteriodetes and sulfate reducing Deltaproteobacteria...
October 6, 2016: Environmental Microbiology
Lydia Krasper, Hauke Lilie, Anja Kublik, Lorenz Adrian, Ralph Golbik, Ute Lechner
: Reductive dehalogenases are essential enzymes in organohalide respiration and consist of a catalytic subunit A and a membrane protein B, encoded by rdhAB genes. Thirty-two rdhAB genes exist in the genome of Dehalococcoides mccartyi strain CBDB1. To gain a first insight into the regulation of rdh operons, the control of gene expression of two rdhAB genes (cbdbA1453/cbdbA1452 and cbdbA1455/cbdbA1454) by the MarR-type regulator Rdh2R (cbdbA1456) encoded directly upstream was studied using heterologous expression and in vitro studies...
December 1, 2016: Journal of Bacteriology
B Matturro, M Di Lenola, C Ubaldi, S Rossetti
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...
November 15, 2016: Marine Pollution Bulletin
Emilie Lefevre, Ellen Cooper, Heather M Stapleton, Claudia K Gunsch
The increasing occurrence of tetrabromobisphenol A (TBBPA) in the environment is raising questions about its potential ecological and human health impacts. TBBPA is microbially transformed under anaerobic conditions to bisphenol A (BPA). However, little is known about which taxa degrade TBBPA and the adaptation of microbial communities exposed to TBBPA. The objectives of this study were to characterize the effect of TBBPA on microbial community structure during the start-up phase of a bench-scale anaerobic sludge reactor, and identify taxa that may be associated with TBBPA degradation...
2016: PloS One
Sebastian Glatt, Rene Zabel, Olga Kolaj-Robin, Osita F Onuma, Florence Baudin, Andrea Graziadei, Valerio Taverniti, Ting-Yu Lin, Frauke Baymann, Bertrand Séraphin, Karin D Breunig, Christoph W Müller
During translation elongation, decoding is based on the recognition of codons by corresponding tRNA anticodon triplets. Molecular mechanisms that regulate global protein synthesis via specific base modifications in tRNA anticodons are receiving increasing attention. The conserved eukaryotic Elongator complex specifically modifies uridines located in the wobble base position of tRNAs. Mutations in Elongator subunits are associated with certain neurodegenerative diseases and cancer. Here we present the crystal structure of D...
September 2016: Nature Structural & Molecular Biology
Li-Lian Wen, Qiang Yang, Zhao-Xin Zhang, Yang-Yi Yi, Youneng Tang, He-Ping Zhao
This work evaluated the interaction of perchlorate and trichloroethene (TCE), two common co-contaminants in groundwater, during bioreduction in serum bottles containing synthetic mineral salts media and microbial consortia. TCE at concentrations up to 0.3mM did not significantly affect perchlorate reduction; however, perchlorate concentrations higher than 0.1mM made the reduction of TCE significantly slower. Perchlorate primarily inhibited the reduction of vinyl chloride (VC, a daughter product of TCE) to ethene...
November 15, 2016: Science of the Total Environment
Martina Praveckova, Maria V Brennerova, Christof Holliger, Felippe De Alencastro, Pierre Rossi
Although polychlorinated biphenyls (PCBs) production was brought to a halt 30 years ago, recalcitrance to degradation makes them a major environmental pollutant at a global scale. Previous studies confirmed that organohalide-respiring bacteria (OHRB) were capable of utilizing chlorinated congeners as electron acceptor. OHRB belonging to the Phyla Chloroflexi and Firmicutes are nowadays considered as the main PCB-dechlorinating organisms. In this study, we aimed at exploring the involvement of other taxa in PCB dechlorination using sediment-free microcosms (SFMs) and the Delor PCB mixture...
2016: Frontiers in Microbiology
S Y Wang, S C Chen, Y C Lin, Y C Kuo, J Y Chen, C M Kao
To enhance the reductive dechlorination of 1,2-dichloroethane (DCA) in groundwater, substrate injection may be required. However, substrate biodegradation causes groundwater acidification and sulfide production, which inhibits the bacteria responsible for DCA dechlorination and results in an odor problem. In the microcosm study, the effectiveness of the addition of ferrous sulfate (FS), desulfurization slag (DS), and nanoscale zero-valent iron (nZVI) on acidification and sulfide control was studied during reductive dechlorination of DCA, and the emulsified substrate (ES) was used as the substrate...
October 2016: Chemosphere
Shu Zhang, Zhen Hou, Xiao-Ming Du, Dong-Ming Li, Xiao-Xia Lu
Site in a former chemical manufacture plant in China was found contaminated with high level of chlorinated volatile organic compounds (CVOCs). The major contaminants chloroform (CF), 1,2-dichloroethane (1,2-DCA) and vinyl chloride (VC) in groundwater were up to 4.49 × 10(4), 2.76 × 10(6) and 4.35 × 10(4) μg/L, respectively. Ethene and methane were at concentrations up to 2219.80 and 165.85 μg/L, respectively. To test the hypothesis that the CVOCs in groundwater at this site could be removed via biodegradation, biomarker analyses and microcosm studies were conducted...
June 28, 2016: Biodegradation
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