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Sulfur-mediated electron shuttling during bacterial iron reduction.

Science (New York, N.Y.) (2014-05-03)
Theodore M Flynn, Edward J O'Loughlin, Bhoopesh Mishra, Thomas J DiChristina, Kenneth M Kemner
PMID24789972
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 (S(0)). 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 S(0) 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 S(0)-mediated electron-shuttling pathways.

MATERIALS
Product Number
Brand
Product Description
44890
Sigma-Aldrich
Iron, puriss. p.a., carbonyl-Iron powder, low in magnesium and manganese compounds, ≥99.5% (RT)
IRMM524B
Iron, IRMM®, certified reference material, 0.5 mm wire
GF65000573
Iron, foil, not light tested, 150x150mm, thickness 0.008mm, 99.85%
GF66169020
Iron, foil, not light tested, 50x50mm, thickness 0.001mm, 99.85%
GF56935604
Iron, foil, 10mm disks, thickness 0.15mm, hard, 99.5%
GF02717502
Iron, wire reel, 0.5m, diameter 0.25mm, hard, 99.99+%
GF93790727
Iron, foil, 10m coil, thickness 0.05mm, hard, 99.5%
GF55674164
Iron, tube, 1000mm, outside diameter 5.0mm, inside diameter 4.5mm, wall thickness 0.25mm, as drawn, 99.5%
GF94244339
Iron, tube, 500mm, outside diameter 2.38mm, inside diameter 1.6mm, wall thickness 0.39mm, as drawn, 99.8+%
GF04529695
Iron, wire reel, 10m, diameter 0.25mm, annealed, 99.99+%
GF29558582
Iron, foil, 50x50mm, thickness 2mm, as rolled, 99.99+%
GF61545674
Iron, tube, 100mm, outside diameter 8.0mm, inside diameter 5mm, wall thickness 1.5mm, annealed, 99.5%
GF03803587
Iron, foil, 300x300mm, thickness 2.0mm, as rolled, armco« soft ingot 99.8%
GF04812599
Iron, tube, 500mm, outside diameter 12.0mm, inside diameter 10mm, wall thickness 1.0mm, annealed, 99.5%
GF55306964
Iron, wire reel, 5m, diameter 0.5mm, hard, 99.99+%
GF29986981
Iron, foil, 300x300mm, thickness 0.15mm, hard, 99.5%
GF48972987
Iron, wire reel, 20m, diameter 0.025mm, as drawn, 99.99+%
GF83304828
Iron, tube, 1000mm, outside diameter 25.0mm, inside diameter 21mm, wall thickness 2mm, annealed, 99.5%
GF68134574
Iron, wire reel, 1000m, diameter 0.25mm, hard, 99.5%
GF17409641
Iron, foil, 10m coil, thickness 0.25mm, hard, 99.5%
GF38919279
Iron, tube, 200mm, outside diameter 20.0mm, inside diameter 16mm, wall thickness 2.0mm, annealed, 99.5%
GF58945078
Iron, wire reel, 250m, diameter 0.25mm, hard, 99.5%
GF82602176
Iron, wire reel, 0.05m, diameter 0.5mm, as drawn, 99.998%
GF84152156
Iron, foil, 10mm disks, thickness 0.005mm, 99.85%
GF42269373
Iron, foil, 50x50mm, thickness 3.1mm, as rolled, 99.95%
GF06733818
Iron, tube, 200mm, outside diameter 5.0mm, inside diameter 4.5mm, wall thickness 0.25mm, as drawn, 99.5%
GF15174255
Iron, tube, 200mm, outside diameter 10.6mm, inside diameter 10.0mm, wall thickness 0.3mm, as drawn, 99.8+%
GF35663935
Iron, wire reel, 5m, diameter 0.025mm, as drawn, 99.99+%
GF33764979
Iron, tube, 100mm, outside diameter 12.7mm, inside diameter 9.5mm, wall thickness 1.6mm, annealed, 99.5%
GF11374039
Iron, rod, 200mm, diameter 30mm, as drawn, 98+%