Abstract

Syntrophic interactions between organohalide-respiring and fermentative microorganisms are critical for effective bioremediation of halogenated compounds. This work investigated the effect of ammonium concentration (up to 4 g liter -1 NH4 +-N) on trichloroethene-reducing Dehalococcoides mccartyi and Geobacteraceae in microbial communities fed lactate and methanol. We found that production of ethene by D. mccartyi occurred in mineral medium containing ≤2 g liter -1 NH4 +-N and in landfill leachate. For the partial reduction of trichloroethene (TCE) to cis-dichloroethene (cis-DCE) at ≥1 g liter-1 NH4 +-N, organohalide-respiring dynamics shifted from D. mccartyi and Geobacteraceae to mainly D. mccartyi. An increasing concentration of ammonium was coupled to lower metabolic rates, longer lag times, and lower gene abundances for all microbial processes studied. The methanol fermentation pathway to acetate and H2 was conserved, regardless of the ammonium concentration provided. However, lactate fermentation shifted from propionic to acetogenic at concentrations of ≥2 g liter-1 NH4 +-N. Our study findings strongly support a tolerance of D. mccartyi to high ammonium concentrations, highlighting the feasibility of organohalide respiration in ammonium-contaminated subsurface environments.

Original languageEnglish (US)
Article numbere00053-16
JournalmSphere
Volume1
Issue number2
DOIs
StatePublished - Mar 1 2016

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Keywords

  • Ammonia
  • Dehalococcoides mccartyi
  • Fermentation
  • Geobacter
  • Organohalide respiration
  • Trichloroethene

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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