Polaromonas sp. JS666

Polaromonas (strain JS666 / ATCC BAA-500), a member of the family Comamonadaceae in the beta-proteobacteria, is a novel, aerobic, cis-dichloroethene (cDCE)-assimilating organism with optimum growth at 20-25 degrees C. It is closely related to the Antarctic marine isolate Polaromonas vacuolata. The substantial phylogenetic distance from other known aerobic alkene-assimilating bacteria suggests a novel biochemistry for cDCE oxidation. Polaromonas is the only aerobic organism known to use cDCE for energy and growth. cDCE is a common groundwater contaminant derived mainly from incomplete anaerobic reductive dechlorination of the widely used chlorinated solvents tetrachloroethene and trichloroethene. The toxicity and suspected carcinogenicity of cDCE qualifies it as an EPA priority pollutant. Since growth-coupled oxidation of cDCE does not appear to be common at field sites, JS666 is a prime candidate for bioremediation at sites where cDCE has migrated into aerobic zones. Recently, a Polaromonas was reported to be the organism responsible for in situ biodegradation of naphthalene at a coal-tar-contaminated site. Closely related strains have also been found recently in a variety of contaminated sites, but their roles are unknown. The recent isolation of the above strains suggests that members of the genus Polaromonas play a major role in the subsurface degradation of environmental contaminants that has been overlooked to date because of an emphasis on mesophilic bacteria. (EBI Integr8)