Accumulation and efflux of polychlorinated biphenyls in Escherichia coli

Shen Geng, Jun Fang, Kendrick B. Turner, Sylvia Daunert, Yinan Wei

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Polychlorinated biphenyls (PCBs) are environmental pollutants that have been associated with numerous adverse health effects in human and animals. Hydroxylated PCBs (HPCBs) are the product of the oxidative metabolism of PCBs. The presence of hydroxyl groups in HPCBs makes these compounds more hydrophilic than the parent PCBs. One of the best approaches to break down and remove these contaminants is bioremediation; an environmentally friendly process that uses microorganisms to degrade hazardous chemicals into non-toxic ones. In this study, we investigated the cellular accumulation and toxicity of selected PCBs and HPCBs in Gram-negative bacteria, using Escherichia coli as a model organism.We found that none of the five PCBs tested were toxic to E. coli, presumably due to their limited bioavailability. Nevertheless, different HPCBs tested showed different levels of toxicity. Furthermore, we demonstrated that the primary multidrug efflux system in E. coli, AcrAB-TolC, facilitated the efflux of HPCBs out of the cell. Since AcrAB-TolC is constitutively expressed in E. coli and is conserved in all sequenced Gram-negative bacterial genomes, our results suggest that the efflux activities of multidrug resistant pumps may affect the accumulation and degradation of PCBs in Gram-negative bacteria.

Original languageEnglish
Pages (from-to)2403-2409
Number of pages7
JournalAnalytical and Bioanalytical Chemistry
Issue number8
StatePublished - Jun 2012

Bibliographical note

Funding Information:
Acknowledgments This work was supported in part by National Institute of Environmental Health Sciences to Y. Wei and S. Daunert (grant P42ES07380). S. Daunert and K. Turner are grateful for support from the National Aeronautics and Space Administration. S.D. would like to thank the University of Kentucky for a Gill Eminent Professorship and the Miller School of Medicine of the University of Miami for the Lucille P. Markey Chair in Biochemistry and Molecular Biology.


  • Hydroxylated polychlorinated biphenyl
  • Multidrug efflux pump
  • Toxicity
  • Whole cell sensing

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry


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