Open AccessThe reductive dechlorination of 2,3,4,5‐tetrachlorobiphenyl in three different sediment cultures: evidence for the involvement of phylogenetically similar Dehalococcoides ‐like bacterial populations
Author(s) -
Yan Tao,
LaPara Timothy M.,
Novak Paige J.
Publication year - 2006
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2005.00022.x
Subject(s) - dehalococcoides , biology , population , microbiology and biotechnology , reductive dechlorination , 16s ribosomal rna , estuary , sediment , bacteria , ecology , genetics , chemistry , contamination , paleontology , demography , organic chemistry , vinyl chloride , sociology , copolymer , polymer
Anaerobic cultures capable of reductively dechlorinating 2,3,4,5‐tetrachlorobiphenyl (CB) were enriched from three different sediments, one estuarine, one marine and one riverine. Two different electron donors were used in enrichments with the estuarine sediment (elemental iron or a mixture of fatty acids). The removal of doubly flanked meta and para chlorines to form 2,3,5‐CB and 2,4,5‐CB was observed in all cultures. Bacterial community analysis of PCR‐amplified 16S rRNA gene fragments revealed different communities in these cultures, with the exception of one common population that showed a high phylogentic relatedness to Dehalococcoides species. No Dehalococcoides ‐like populations were ever detected in control cultures to which no PCBs were added. In addition, the dynamics of this Dehalococcoides ‐like population were strongly correlated with dechlorination. Subcultures of the estuarine sediment culture demonstrated that the Dehalococcoides ‐like population disappeared when dechlorination was inhibited with 2‐bromoethanesulfonate or when 2,3,4,5‐CB had been consumed. These results provide evidence that Dehalococcoides ‐like populations were involved in the removal of doubly flanked chlorines from 2,3,4,5‐CB. Furthermore, the successful enrichment of these populations from geographically distant and geochemically distinct environments indicates the widespread presence of these PCB‐dechlorinating, Dehalococcoides ‐like organisms.