Dehalococcoides

In the genus Dehalococcoides is the only group of bacteria which are capable of reductive dehalogenation of chlorinated benzenes, polychlorinated dioxins, polychlorinated biphenyls and chlorinated ethenes. So far, six strains were isolated ( 195, CBDB1, FL2, BAV1, VC, and GT), five of them in the U.S.. Strain CBDB1 was isolated from the anoxic sediment of the river Saale.

Genome Research

The genomes of two of the previously known and cultivated species of the genus Dehalococcoides have been completely sequenced. The sequences are among the smallest genomes known so far free of live bacteria. From the sequences can be deduced that both agents are highly specialized in the reductive dechlorination as an energy source. In strain CBDB1 32 complete operon have been found that are homologous to reductive dehalogenases in strain 18 195 of these genes. However, no gene for nitrate, sulfate, or fumarate is present in the genome and of genes that could encode a cell wall synthesis is missing.

A more detailed knowledge of the biochemical activities of the encoded enzymes of Dehalococcoides would allow it predict the Dehalogenierungspotenzial of Dehalococcoides populations in contaminated areas of the environment accurately and biotechnological use.

The best known and most researched species D. ethenogenes builds toxic chlorinated hydrocarbons such as chloroethene, chlorophenol and polychlorinated biphenyls and dioxins from to harmless ethene.