| abstract |
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Dehalogenating Chloroflexi, such as Dehalococcoides (Dhc), are members of the rare biosphere of deep sea sediments but were originally discovered as the key microbes mediating reductive dehalogenation of the prevalent groundwater contaminants tetrachloroethene and trichloroethene to ethane. Dhc that have been cultivated from contaminated sites so far are slow growing, highly niche adapted, strictly anaerobic microbes, that depend on a supporting microbial community for electron donor and cofactor requirements among other factors. Molecular and genomic studies on the key enzyme reductive dehalogenase encoded by rdh genes, have provided evidence for a rapid adaptive evolution of Dhc and rdh. However, the metabolic life style of Dhc in the absence of anthropogenic contaminants is still unknown. To understand the natural habitat of this unique and important microbial species an analysis on non-contaminated deep sea sediment samples by molecular and single cell genomic approaches was initiated. The research provided fundamental insights into life style, genomic population structure and evolution of Dhc. Derived correlations may help to assess biodegradative potential for reductive dehalogenation and to identify optimal engineering conditions leading to a more effective management of bioremediation strategies. In addition, this research will be able to answer questions about life within the poorly understood oligotrophic marine surface. |
