Bacterial community analysis of shallow groundwater undergoing sequential anaerobic and aerobic chloroethene biotransformation

Todd R. Miller, Mark P. Franklin, Rolf U. Halden

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


At Department of Energy Site 300, beneficial hydrocarbon cocontaminants and favorable subsurface conditions facilitate sequential reductive dechlorination of trichloroethene (TCE) and rapid oxidation of the resultant cis-dichloroethene (cis-DCE) upon periodic oxygen influx. We assessed the geochemistry and microbial community of groundwater from across the site. Removal of cis-DCE was shown to coincide with oxygen influx in hydrocarbon-containing groundwater near the source area. Principal component analysis of contaminants and inorganic compounds showed that monitoring wells could be differentiated based upon concentrations of TCE, cis-DCE, and nitrate. Structurally similar communities were detected in groundwater from wells containing cis-DCE, high TCE, and low nitrate levels. Bacteria identified by sequencing 16S rRNA genes belonged to seven phylogenetic groups, including Alpha-, Beta-, Gamma- and Deltaproteobacteria, Nitrospira, Firmicutes and Cytophaga-Flexibacter- Bacteroidetes (CFB). Whereas members of the Burkholderiales and CFB group were abundant in all wells (104-109 16S rRNA gene copies L -1), quantitative PCR showed that Alphaproteobacteria were elevated (>106 L-1) only in wells containing hydrocarbon cocontaminants. The study shows that bacterial community structure is related to groundwater geochemistry and that Alphaproteobacteria are enriched in locales where cis-DCE removal occurs.

Original languageEnglish (US)
Pages (from-to)299-311
Number of pages13
JournalFEMS microbiology ecology
Issue number2
StatePublished - May 2007
Externally publishedYes


  • Dichloroethene
  • Diesel
  • Tetraalkoxysilane
  • Trichloroethylene

ASJC Scopus subject areas

  • Microbiology
  • Ecology
  • Applied Microbiology and Biotechnology


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