PCR-based Identification of Environmental Microbes
BCI uses a genetic method (Polymerase Chain Reaction) for detecting the presence of the unique PCE degrading bacterium, Dehalococcoides ethenogenes, in groundwater. Under the right geobiochemical conditions, it can transform not only PCE but its metabolic products TCE, cis-DCE or vinyl chloride to ethene. BCI’s PCR-based identification has been expanded to include Dehalobacter species involved in the reductive dechlorination of 1,1,1-trichloroethane (TCA) and 1,1-dichloroethane (DCA).
In order to test for the presence of Dehalococcoides ethenogenes in site groundwater, BCI extracts DNA from about 1 liter of groundwater and tests for the presence of its unique genes by PCR. The test is very specific, and provides evidence for the presence of this valuable microbe at the site. Combining genetic identification by PCR with functional microcosm testing provides a clear picture of natural attenuation occuring at the site, as well as the potential for enhanced bioremediation.
For each groundwater sample submitted for PCR analysis, we also analyze for the presence of ethene and vinyl chloride (VC), the products of active D. ethenogenes. BCI uses a very sensitive method for detecting these compounds (detection limits for ethene and VC are 0.05 µg/L and 1 µg/L respectively). BCI has established a strong positive correlation between the presence of these compounds and the presence of active Dehalococcoides ethenogenes in groundwater.
In the case of Dehalobacter, we also analyze groundwater for the presence of chloroethane, the transformation product of active Dehalobacter.