ISOLATION AND CHARACTERIZATION OF DEHALOGENATORS THAT DETOXIFY POLYBROMINATED DIPHENYL ETHERS AND CHLORINATED ALKANES

Abstract

Halogenated compounds have caused significant environment pollutions, posing a major threat to public health. This study reports isolation of four anaerobic strains that possess novel dehalogenation capabilities on polybrominated diphenyl ethers (PBDEs), chloroform, and 1,1,1-trichloroethane (TCA). Acetobacterium sp. strain AG and Dehalococcoides sp. strain DG from the mixed culture G debrominate octa-BDEs and penta-BDEs via a co-metabolic process. Dehalococcoides mccartyi strain GY50 from coculture GY2, on the contrary, metabolically debrominates the penta-BDE mixture completely to diphenyl ether. Three reductive dehalogenase homologues genes in strain GY50 – pbrA1, pbrA2, and pbrA3 are responsible for PBDE debromination. Lastly, from the mixed culture PR, Desulfitobacterium sp. strain PR was isolated that rapidly dechlorinates TCA and chloroform. The gene ctrA in strain PR was identified to be responsible for dechlorination of both TCA and chloroform. This study provides promising candidates for bioremediation of halogenated compounds, and revealed important genetic information related to the dehalogenation process.