Polychlorinate ibenzo-p-ioxins (PCDDs) are release into the environment from a variety of both anthropogenic an natural sources. While highly chlorinate ibenzo-p-ioxins are persistent uner oxic conitions, in anoxic environments, these organohalogens can be reuctively echlorinate to less chlorinate compouns that are then more amenable to subsequent aerobic egraation. Ientifying the microorganisms responsible for echlorination is an important step in eveloping bioremeiation approaches. In this stuy, we emonstrate the use of a DNA-stable isotope probing (SIP) approach to ientify the bacteria active in echlorination of PCDDs in river seiments, with 1,2,3,4-tetrachloroibenzo-p-ioxin (1,2,3,4-TeCDD) as a moel. In aition, pyrosequencing of reverse transcribe 16S rRNA of TeCDD echlorinating enrichment cultures was use to reveal active members of the bacterial community. A set of operational taxonomic units (OTUs) respone positively to the aition of 1,2,3,4-TeCDD in SIP microcosms assimilating 13C-acetate as the carbon source. Analysis of bacterial community profiles of the 13C labele heavy DNA fraction reveale that an OTU corresponing to Dehalococcoies mccartyi accounte for a significantly greater abunance in cultures amene with 1,2,3,4-TeCDD than in cultures without 1,2,3,4-TeCDD. This implies the involvement of this Dehalococcoies mccartyi strain in the reuctive echlorination of 1,2,3,4-TeCDD an suggests the applicability of SIP for a robust assessment of the bioremeiation potential of organohalogen contaminate sites.
All Science Journal Classification (ASJC) codes
- Environmental Chemistry