Details
| Original language | English |
|---|---|
| Pages (from-to) | 133-147 |
| Number of pages | 15 |
| Journal | Chemical geology |
| Volume | 447 |
| Publication status | Published - 30 Dec 2016 |
Abstract
Despite numerous studies seeking to elucidate the effect of various specific organic compounds on the reactivity and stability of Fe oxyhydroxides in soil, studies examining the effect of natural organic matter (NOM) on the microbial reduction of Fe-organic matter (OM) coprecipitates are still rare. In this study, pure ferrihydrite (Fh) and Fe-OM coprecipitates were synthesized using three different types of NOM (extracellular polymeric substances extracted from Bacillus subtilis, OM extracted from the Oi horizon of a Cambisol, and OM extracted from the Oa horizon of a Podzol). These phases were characterized by N2 gas adsorption, nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), NOM desorption experiments, and mediated electrochemical reduction (MER). Iron(III) reduction under anaerobic conditions was monitored for 16 days using two different strains of dissimilatory Fe(III)-reducing bacteria (Shewanella putrefaciens, Geobacter metallireducens). Mineral transformation during reduction was determined by XRD and FTIR of the solid post-incubation phases. Fe(III) reduction by Shewanella putrefaciens was influenced by the amount of available electron shuttling molecules provided by the NOM, whereas the Fe(III) reduction by Geobacter metallireducens as well as abiotic Fe(III) reduction was influenced by particle size and NOM-induced aggregation. The specific surface area proved to be a poor predictor of Fe reduction of Fe-OM coprecipitates. This study emphasizes that certain physicochemical properties of natural Fe oxyhydroxides (composition of sorbed NOM and aggregation state) impact the Fe reduction by distinct microorganisms to differing degrees. Understanding environmental Fe and C cycling, therefore, requires experimental approaches extending beyond the use of pure Fe oxyhydroxides and model organisms.
Keywords
- Extracellular polymeric substances, Geobacter metallireducens, Iron oxyhydroxides, Mediated electrochemical reduction, Natural organic matter, Shewanella putrefaciens
ASJC Scopus subject areas
- Earth and Planetary Sciences(all)
- Geology
- Earth and Planetary Sciences(all)
- Geochemistry and Petrology
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In: Chemical geology, Vol. 447, 30.12.2016, p. 133-147.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Microbial reduction of ferrihydrite-organic matter coprecipitates by Shewanella putrefaciens and Geobacter metallireducens in comparison to mediated electrochemical reduction
AU - Poggenburg, Christine
AU - Mikutta, Robert
AU - Sander, Michael
AU - Schippers, Axel
AU - Marchanka, Alexander
AU - Dohrmann, Reiner
AU - Guggenberger, Georg
PY - 2016/12/30
Y1 - 2016/12/30
N2 - Despite numerous studies seeking to elucidate the effect of various specific organic compounds on the reactivity and stability of Fe oxyhydroxides in soil, studies examining the effect of natural organic matter (NOM) on the microbial reduction of Fe-organic matter (OM) coprecipitates are still rare. In this study, pure ferrihydrite (Fh) and Fe-OM coprecipitates were synthesized using three different types of NOM (extracellular polymeric substances extracted from Bacillus subtilis, OM extracted from the Oi horizon of a Cambisol, and OM extracted from the Oa horizon of a Podzol). These phases were characterized by N2 gas adsorption, nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), NOM desorption experiments, and mediated electrochemical reduction (MER). Iron(III) reduction under anaerobic conditions was monitored for 16 days using two different strains of dissimilatory Fe(III)-reducing bacteria (Shewanella putrefaciens, Geobacter metallireducens). Mineral transformation during reduction was determined by XRD and FTIR of the solid post-incubation phases. Fe(III) reduction by Shewanella putrefaciens was influenced by the amount of available electron shuttling molecules provided by the NOM, whereas the Fe(III) reduction by Geobacter metallireducens as well as abiotic Fe(III) reduction was influenced by particle size and NOM-induced aggregation. The specific surface area proved to be a poor predictor of Fe reduction of Fe-OM coprecipitates. This study emphasizes that certain physicochemical properties of natural Fe oxyhydroxides (composition of sorbed NOM and aggregation state) impact the Fe reduction by distinct microorganisms to differing degrees. Understanding environmental Fe and C cycling, therefore, requires experimental approaches extending beyond the use of pure Fe oxyhydroxides and model organisms.
AB - Despite numerous studies seeking to elucidate the effect of various specific organic compounds on the reactivity and stability of Fe oxyhydroxides in soil, studies examining the effect of natural organic matter (NOM) on the microbial reduction of Fe-organic matter (OM) coprecipitates are still rare. In this study, pure ferrihydrite (Fh) and Fe-OM coprecipitates were synthesized using three different types of NOM (extracellular polymeric substances extracted from Bacillus subtilis, OM extracted from the Oi horizon of a Cambisol, and OM extracted from the Oa horizon of a Podzol). These phases were characterized by N2 gas adsorption, nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), NOM desorption experiments, and mediated electrochemical reduction (MER). Iron(III) reduction under anaerobic conditions was monitored for 16 days using two different strains of dissimilatory Fe(III)-reducing bacteria (Shewanella putrefaciens, Geobacter metallireducens). Mineral transformation during reduction was determined by XRD and FTIR of the solid post-incubation phases. Fe(III) reduction by Shewanella putrefaciens was influenced by the amount of available electron shuttling molecules provided by the NOM, whereas the Fe(III) reduction by Geobacter metallireducens as well as abiotic Fe(III) reduction was influenced by particle size and NOM-induced aggregation. The specific surface area proved to be a poor predictor of Fe reduction of Fe-OM coprecipitates. This study emphasizes that certain physicochemical properties of natural Fe oxyhydroxides (composition of sorbed NOM and aggregation state) impact the Fe reduction by distinct microorganisms to differing degrees. Understanding environmental Fe and C cycling, therefore, requires experimental approaches extending beyond the use of pure Fe oxyhydroxides and model organisms.
KW - Extracellular polymeric substances
KW - Geobacter metallireducens
KW - Iron oxyhydroxides
KW - Mediated electrochemical reduction
KW - Natural organic matter
KW - Shewanella putrefaciens
UR - http://www.scopus.com/inward/record.url?scp=84999851954&partnerID=8YFLogxK
U2 - 10.1016/j.chemgeo.2016.09.031
DO - 10.1016/j.chemgeo.2016.09.031
M3 - Article
AN - SCOPUS:84999851954
VL - 447
SP - 133
EP - 147
JO - Chemical geology
JF - Chemical geology
SN - 0009-2541
ER -