1. Sulfur-mediated electron shuttling during bacterial iron reduction.
- Author
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Flynn, Theodore M., O'Loughlin, Edward J., Mishra, Bhoopesh, DiChristina, Thomas J., and Kemner, Kenneth M.
- Subjects
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ELECTROPHILES , *THERMODYNAMIC cycles , *GOETHITE , *AQUIFERS , *SHEWANELLA oneidensis - Abstract
Microbial reduction of ferric iron [Fe(III)] is an important biogeochemical process in anoxic aquifers. Depending on groundwater pH, dissimilatory metal-reducing bacteria can also respire alternative electron acceptors to survive, including elemental sulfur (S0). To understand the interplay of Fe/S cycling under alkaline conditions, we combined thermodynamic geochemical modeling with bioreactor experiments using Shewanella oneidensis MR-1. Under these conditions, S. oneidensis can enzymatically reduce S0 but not goethite (α-FeOOH). The HS- produced subsequently reduces goethite abiotically. Because of the prevalence of alkaline conditions in many aquifers, Fe(III) reduction may thus proceed via S0-mediated electron-shuttling pathways. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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