Biostimulation induces syntrophic interactions that impact C,S and N cycling in a
sediment microbial community |
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Authors: | Kim M Handley Nathan C VerBerkmoes Carl I Steefel Kenneth H Williams Itai Sharon Christopher S Miller Kyle R Frischkorn Karuna Chourey Brian C Thomas Manesh B Shah Philip E Long Robert L Hettich Jillian F Banfield |
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Institution: | 1.Department of Earth and Planetary Science,
University of California, Berkeley, CA, USA;2.Chemical Sciences and Biosciences Divisions,
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN, USA;3.Earth Science Division, Lawrence Berkeley
National Laboratory (LBNL), Berkeley, CA, USA |
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Abstract: | Stimulation of subsurface microorganisms to induce reductive immobilization of metals is
a promising approach for bioremediation, yet the overall microbial community response is
typically poorly understood. Here we used proteogenomics to test the hypothesis that
excess input of acetate activates complex community functioning and syntrophic
interactions among autotrophs and heterotrophs. A flow-through sediment column was
incubated in a groundwater well of an acetate-amended aquifer and recovered during
microbial sulfate reduction. De novo reconstruction of community sequences
yielded near-complete genomes of Desulfobacter (Deltaproteobacteria),
Sulfurovum- and Sulfurimonas-like Epsilonproteobacteria and
Bacteroidetes. Partial genomes were obtained for Clostridiales
(Firmicutes) and Desulfuromonadales-like Deltaproteobacteria.
The majority of proteins identified by mass spectrometry corresponded to
Desulfobacter-like species, and demonstrate the role of this organism in
sulfate reduction (Dsr and APS), nitrogen fixation and acetate oxidation to CO2
during amendment. Results indicate less abundant Desulfuromonadales, and possibly
Bacteroidetes, also actively contributed to CO2 production via the
tricarboxylic acid (TCA) cycle. Proteomic data indicate that sulfide was partially
re-oxidized by Epsilonproteobacteria through nitrate-dependent sulfide oxidation
(using Nap, Nir, Nos, SQR and Sox), with CO2 fixed using the reverse TCA cycle.
We infer that high acetate concentrations, aimed at stimulating anaerobic heterotrophy,
led to the co-enrichment of, and carbon fixation in Epsilonproteobacteria.
Results give an insight into ecosystem behavior following addition of simple organic
carbon to the subsurface, and demonstrate a range of biological processes and community
interactions were stimulated. |
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Keywords: | autotroph metagenomics proteomics sediment subsurface syntrophy |
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