title: Geochemical and microbial community determinants of reductive dechlorination at a site biostimulated with glycerol.
abstract: 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. In line with13C cDCE enrichment and increased Dehalococcoides mccartyi (Dcm) numbers, dechlorination was observed toward the end of the field experiment, albeit being incomplete with accumulation of vinyl chloride. This was concurrent with (i) decreased concentrations of dissolved organic carbon (DOC), reduced relative abundances of fermenting and sulfate reducing bacteria that have been suggested to promote Dcm growth by providing electron donor (H2) and essential corrinoid cofactors, (ii) increased sulfate concentration and increased relative abundance of Epsilonproteobacteria and Deferribacteres as putative oxidizers of reduced sulfur compounds. Strong correlations of DOC, relative abundance of fermenters and sulfate reducers, and dechlorination imply the importance of syntrophic interactions to sustain robust dechlorination. Tracking microbial and environmental parameters that promote/preclude enhanced reductive dechlorination should aid development of sustainable bioremediation strategies.
authors.affiliation: Flemish Institute for Technological Research (VITO), Separation and Conversion Technology, Boeretang 200, 2400 Mol, Belgium.|Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.|Division of Soil and Water Management, KU Leuven, Kasteelpark Arenberg 20, Heverlee, B-3001, Belgium.
authors.forename: Siavash
authors.initials: S
authors.lastname: Atashgahi
authors.affiliation: Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.
authors.forename: Yue
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, The Netherlands.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Saccenti
authors.affiliation: Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, The Netherlands.
authors.forename: Maria
authors.initials: M
authors.lastname: Suarez-Diez
authors.affiliation: Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.|Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Wageningen, The Netherlands.
authors.forename: Javier
authors.initials: J
authors.lastname: Ramiro-Garcia
authors.affiliation: Isodetect GmbH, Ingolstädter Landstrasse 1, Neuherberg, D-85764, Germany.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Eisenmann
authors.affiliation: Institute of Groundwater Ecology, Helmholtz Zentrum München-National Research Center for Environmental Health, Ingolstädter Landstrasse 1, Neuherberg, D-85764, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Elsner
authors.affiliation: Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.|Centre of Biological Engineering, University of Minho, Braga, Portugal.
authors.forename: Alfons
authors.initials: A
authors.lastname: J M Stams
authors.affiliation: Division of Soil and Water Management, KU Leuven, Kasteelpark Arenberg 20, Heverlee, B-3001, 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.
authors.forename: Winnie
authors.initials: W
authors.lastname: Dejonghe
authors.affiliation: Laboratory of Microbiology, Wageningen University & Research, Wageningen, The Netherlands.
authors.forename: Hauke
authors.initials: H
authors.lastname: Smidt
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D041862:Chloroflexi / Q000235:genetics / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism*; D060587:Groundwater; D054879:Halogenation; D010084:Oxidation-Reduction; D012336:RNA, Ribosomal, 16S; D014752:Vinyl Chloride; D014871:Water Microbiology; D014874:Water Pollutants, Chemical
chemical_list: D005030:Ethylenes; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical; C036216:ethylene; D005990:Glycerol; D014752:Vinyl Chloride