Fluorescence in situhybridization image of Dehalococcoidescells (pink)
in a dechlorinatingmethanogenicculture. (Courtesy of Natuschka M. Lee, Technical University of Munich, Germany and Frank E. Löffler, Georgia Institute of Technology, USA)
Groundwater sites contaminated with compounds such as trichloroethene (TCE), a pervasive organic groundwater pollutant often used by industry as cleansers or degreasers.Dehalococcoidesbacteria, often found in a community of other microorganisms at groundwater sites contaminated with these compounds, can break down TCE and convert it into ethene, a harmless chemical compound often used to help ripen fruits.
In an article published online March 1, 2012 in The ISME Journal a team of researchers including DOE JGI MetagenomeProgram Lead Susannah Tringe conducted a metagenomic analysis of a stable dechlorinating community derived from sediment collected at the Alameda Naval Air Station (ANAS) in California. The analysis allowed the team to characterize the members of this microbial community, particularly those involved in dechlorinationas microbes such as Dehalococcoidesare known to more effectively dechlorinatechemicals in the presence of other microorganisms.
The researchers’ data suggested that all of the genes that code for enzymes involved in dechlorinationwere associated with Dehalococcoides, suggesting its importance as the dominant dechlorinatingmicrobe in the ANAS microbial community. Additionally, they found that though the various microbes in the community had widely varying roles as hydrogen producers and consumers, “in this community, they appear to have developed working syntrophic [mutually dependent] relationships, allowing stable long-term dechlorinationactivity.”