Dichloromethane (DCM) is a toxic, persistent groundwater contaminant that is most commonly of anthropogenic origin. It is present at numerous contaminated sites worldwide, as demonstrated by its occurrence at 19% of National Priority List sites throughout the United States, and also typically produced as a breakdown product of trichloromethane, another common groundwater pollutant. As DCM is denser than water, it tends to sink to the bottom of the water table, forming dense non-aqueous phase liquid (DNAPL) pools, from which a steady stream of contaminant can slowly leach into the groundwater over long time periods.
Strain DCMF is a recently discovered bacterium enriched from a contaminated aquifer near Botany Bay, Australia, that transforms DCM to acetate under fermentative conditions. Not only does this novel member of the Peptococcaceae family have great potential in the Australian bioremediation scene, it also represents a unique branch on the phylogenetic tree of life. The genome of strain DCMF was recently sequenced and assembled into a single, 6.4 Mb circular contig. It revealed a host of interesting predicted metabolic features including a highly redundant set of methylamine methyltransferases, suggesting they have a key role in dechlorination. This work characterizes a robust bacterial culture for the bioremediation of DCM-contaminated groundwater and paves the way to identifying a novel dehalogenase capable of anaerobic DCM degradation.