title: Kinetics of dechlorination by Dehalococcoides mccartyi using different carbon sources.
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.
authors.affiliation: Flemish Institute for Technological Research (VITO), Environmental Modeling Unit, Boeretang 200, 2400 Mol, Belgium; Ghent University, Department of Soil Management, Coupure Links 653, 9000 Ghent, Belgium.
authors.forename: Uwe
authors.initials: U
authors.lastname: Schneidewind
authors.affiliation: Flemish Institute for Technological Research (VITO), Separation and Conversion Technology, Boeretang 200, 2400 Mol, Belgium.
authors.forename: Pieter Jan
authors.initials: PJ
authors.lastname: Haest
authors.affiliation: Flemish Institute for Technological Research (VITO), Separation and Conversion Technology, Boeretang 200, 2400 Mol, Belgium; Wageningen University, Laboratory of Microbiology, 6703 HB Wageningen, The Netherlands; KU Leuven, Division Soil and Water Management, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium.
authors.forename: Siavash
authors.initials: S
authors.lastname: Atashgahi
authors.affiliation: Wageningen University, Laboratory of Microbiology, 6703 HB Wageningen, The Netherlands.
authors.forename: Farai
authors.initials: F
authors.lastname: Maphosa
authors.affiliation: Flemish Institute for Technological Research (VITO), Separation and Conversion Technology, Boeretang 200, 2400 Mol, Belgium.
authors.forename: Kelly
authors.initials: K
authors.lastname: Hamonts
authors.affiliation: Flemish Institute for Technological Research (VITO), Separation and Conversion Technology, Boeretang 200, 2400 Mol, Belgium.
authors.forename: Miranda
authors.initials: M
authors.lastname: Maesen
authors.affiliation: Manresa Technology Centre - CTM, Environmental Technology Area, Av. Bases de Manresa, 08242 Manresa, Spain.
authors.forename: Montse
authors.initials: M
authors.lastname: Calderer
authors.affiliation: Flemish Institute for Technological Research (VITO), Environmental Modeling Unit, Boeretang 200, 2400 Mol, Belgium; Ghent University, Department of Soil Management, Coupure Links 653, 9000 Ghent, Belgium; University of Antwerp, Department of Bioscience Engineering, Groenenborgerlaan 171, 2020 Antwerp, Belgium.
authors.forename: Piet
authors.initials: P
authors.lastname: Seuntjens
authors.affiliation: Wageningen University, Laboratory of Microbiology, 6703 HB Wageningen, The Netherlands.
authors.forename: Hauke
authors.initials: H
authors.lastname: Smidt
authors.affiliation: KU Leuven, Division Soil and Water Management, Kasteelpark Arenberg 20, 3001 Heverlee, Belgium.
authors.forename: Dirk
authors.initials: D
authors.lastname: Springael
authors.affiliation: Flemish Institute for Technological Research (VITO), Separation and Conversion Technology, Boeretang 200, 2400 Mol, Belgium. Electronic address: winnie.dejonghe@vito.be.
authors.forename: Winnie
authors.initials: W
authors.lastname: Dejonghe
mesh_terms: D001530:Belgium; D001673:Biodegradation, Environmental; D002244:Carbon / Q000378:metabolism; D002713:Chlorine / Q000378:metabolism; D041862:Chloroflexi / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D004000:Dichloroethylenes / Q000378:metabolism; D060587:Groundwater; D007700:Kinetics; D008954:Models, Biological; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014241:Trichloroethylene / Q000378:metabolism*; D014752:Vinyl Chloride / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D004000:Dichloroethylenes; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical; D014241:Trichloroethylene; D002713:Chlorine; D002244:Carbon; D014752:Vinyl Chloride
keywords: Biodegradation; Chlorinated ethenes; Dechlorination kinetics; Dehalococcoides mccartyi