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Article
Anaerobic Oxidation of Benzene by the Hyperthermophilic Archaeon Ferroglobus Placidus
Applied and Environmental Microbiology (2011)
  • Derek Lovley, University of Massachusetts - Amherst
  • Dawn E Holmes
  • Carla Risso
  • Jessica A Smith
Abstract

Anaerobic benzene oxidation coupled to the reduction of Fe(III) was studied in Ferroglobus placidus in order to learn more about how such a stable molecule could be metabolized under strict anaerobic conditions. F. placidus conserved energy to support growth at 85°C in a medium with benzene provided as the sole electron donor and Fe(III) as the sole electron acceptor. The stoichiometry of benzene loss and Fe(III) reduction, as well as the conversion of [(14)C]benzene to [(14)C]carbon dioxide, was consistent with complete oxidation of benzene to carbon dioxide with electron transfer to Fe(III). Benzoate, but not phenol or toluene, accumulated at low levels during benzene metabolism, and [(14)C]benzoate was produced from [(14)C]benzene. Analysis of gene transcript levels revealed increased expression of genes encoding enzymes for anaerobic benzoate degradation during growth on benzene versus growth on acetate, but genes involved in phenol degradation were not upregulated during growth on benzene. A gene for a putative carboxylase that was more highly expressed in benzene- than in benzoate-grown cells was identified. These results suggest that benzene is carboxylated to benzoate and that phenol is not an important intermediate in the benzene metabolism of F. placidus. This is the first demonstration of a microorganism in pure culture that can grow on benzene under strict anaerobic conditions and for which there is strong evidence for degradation of benzene via clearly defined anaerobic metabolic pathways. Thus, F. placidus provides a much-needed pure culture model for further studies on the anaerobic activation of benzene in microorganisms.

Disciplines
Publication Date
September, 2011
Publisher Statement
This article was harvested from PubMed Central. DOI: 10.1128/​AEM.05452-11
Citation Information
Derek Lovley, Dawn E Holmes, Carla Risso and Jessica A Smith. "Anaerobic Oxidation of Benzene by the Hyperthermophilic Archaeon Ferroglobus Placidus" Applied and Environmental Microbiology Vol. 77 (2011)
Available at: http://works.bepress.com/derek_lovley/4/