Anaerobic microbial reductive dechlorination of tetrachloroethene to predominately trans-1,2-dichloroethene.
While most sites and all characterized PCE and TCE dechlorinating anaerobic bacteria produce cis-DCE as the major DCE isomer, significant amounts of trans-DCE are found in the environment. We have obtained microcosms from some sites and enrichment cultures that produce more trans-DCE than cis-DCE. These cultures reductively dechlorinated PCE and TCE to trans-DCE and cis-DCE simultaneously and in a ratio of 3(+/-0.5):1 that was stable through serial transfers with a variety of electron donors and occurred in both methanogenic and nonmethanogenic enrichments. Two sediment-free, nonmethanogenic enrichment cultures produced trans-DCE at rates of up to 2.5 micromol L(-1) day(-1). Dehalococcoides populations were detected in both trans-DCE producing cultures by their 16S rRNA gene sequences, and trans-DCE was produced in the presence of ampicillin. Because trans-DCE can be the major product from PCE and TCE microbial dechlorination, high fractions of trans-DCE at chloroethene-contaminated sites are not necessarily from source contamination.
Griffin
Benjamin M
BM
Center for Microbial Ecology, Department of Microbiology and Molecular Genetics, and Institute for Environmental Toxicology, Michigan State University, East Lansing, Michigan 48824-1325, USA.
Tiedje
James M
JM
Löffler
Frank E
FE
D001421:Bacteria, Anaerobic; D004000:Dichloroethylenes / Q000737:chemistry; D012997:Solvents / Q000378:metabolism*; D013750:Tetrachloroethylene / Q000378:metabolism*
D004000:Dichloroethylenes; D012997:Solvents; D013750:Tetrachloroethylene; C035384:1,2-dichloroethylene