Microbially catalyzed nitrate-dependent oxidation of biogenic solid-phase Fe(II) compounds

Karrie A. Weber, Flynn W. Picardal, Eric E. Roden

Research output: Contribution to journalArticle

147 Scopus citations

Abstract

The potential for microbially catalyzed NO3--dependent oxidation of solid-phase Fe(II) compounds was examined using a previously described autotrophic, denitrifying, Fe-(II)-oxidizing enrichment culture. The following solid-phase Fe(II)-bearing minerals were considered: microbially reduced synthetic goethite, two different end products of microbially hydrous ferric oxide (HFO) reduction (biogenic Fe3O4 and biogenic FeCO3), chemically precipitated FeCO3, and two microbially reduced iron(III) oxide-rich subsoils. The microbially reduced goethite, subsoils, and chemically precipitated FeCO3 were subject to rapid NO3--dependent Fe(II) oxidation. Significant oxidation of biogenic Fe3O4 was observed. Very little biogenic FeCO3 was oxidized. No reduction of NO3- or oxidation of Fe(II) occurred in pasteurized cultures. The molar ratio of NO3- reduced to Fe(II) oxidized in cultures containing chemically precipitated FeCO3, and one of the microbially reduced subsoils approximated the theoretical stoichiometry of 0.2: 1. However, molar ratios obtained for oxidation of microbially reduced goethite, the other subsoil, and the HFO reduction end products did not agree with this theoretical value. These discrepancies may be related to heterotrophic NO3- reduction coupled to oxidation of dead Fe(III)-reducing bacterial biomass. Our findings demonstrate that microbally catalyzed NO3--dependent Fe(II) oxidation has the potential to significantly accelerate the oxidation of solid-phase Fe(II) compounds by oxidized N species. This process could have an important influence on the migration of contaminant metals and radionuclides in subsurface environments.

Original languageEnglish (US)
Pages (from-to)1644-1650
Number of pages7
JournalEnvironmental Science and Technology
Volume35
Issue number8
DOIs
StatePublished - Apr 15 2001

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry

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