Remediation of DOE sites contaminated with chlorinated ethenes, specifically with tetrachloroethene (PCE)
and trichloroethene (TCE), is a multibillion dollar burden to DOE and society. The use of microorganisms in bioremediation is considered the most cost effective remediation treatment. During natural reductive dehalogenation, TCE (or PCE) reduction is often incomplete and stops at the level of vinyl chloride, which, as a known human carcinogen, is more toxic than the parent compounds. However, vinyl chloride degradation to harmless ethene has been linked to the genus Dehalococcoides, and we have isolated a novel Dehaloccoides species, strain VS, that not only can degrade vinyl chloride but also its parent compound TCE and dichloroethene (DCE) completely to ethene. Each step in the dehalogenation process is coupled to energy conservation and supports growth of strain VS. This unique metabolic capability makes Dehalococcoides sp. strain VS the ideal candidate for large, field-scale bioremediation approaches. Furthermore, we have isolated the enzyme and gene mediating vinyl chloride reduction, and have conducted extensive kinetic, microbiological, and molecular analysis with this strain. We propose to sequence the genome of Dehalococcoides sp. strain VS. The genome sequence will be critical for understanding the unique biology of this organism, its distinctive phylogenetic position, and will enable more effective and efficient engineering approaches for bioremediation of chlorinated solvents at many DOE sites.