Manganese sulfide formation via concomitant microbial manganese oxide and thiosulfate reduction
Article first published online: 27 SEP 2011
© 2011 Society for Applied Microbiology and Blackwell Publishing Ltd
Thematic Issue: Human Microbiome
Volume 13, Issue 12, pages 3275–3288, December 2011
How to Cite
Lee, J.-H., Kennedy, D. W., Dohnalkova, A., Moore, D. A., Nachimuthu, P., Reed, S. B. and Fredrickson, J. K. (2011), Manganese sulfide formation via concomitant microbial manganese oxide and thiosulfate reduction. Environmental Microbiology, 13: 3275–3288. doi: 10.1111/j.1462-2920.2011.02587.x
- Issue published online: 30 NOV 2011
- Article first published online: 27 SEP 2011
- Received 7 June, 2011; accepted 14 August, 2011.
The dissimilatory metal-reducing bacterium, Shewanella oneidensis MR-1 produced γ-MnS (rambergite) nanoparticles during the concurrent reduction of MnO2 and thiosulfate coupled to H2 oxidation. To investigate effect of direct microbial reduction of MnO2 on MnS formation, two MR-1 mutants defective in outer membrane c-type cytochromes (ΔmtrC/ΔomcA and ΔmtrC/ΔomcA/ΔmtrF) were also used and it was determined that direct reduction of MnO2 was dominant relative to chemical reduction by biogenic sulfide generated from thiosulfate reduction. Although bicarbonate was excluded from the medium, incubations of strain MR-1 with lactate as the electron donor produced MnCO3 (rhodochrosite) as well as MnS in nearly equivalent amounts as estimated by micro X-ray diffraction (micro-XRD) analysis. It was concluded that carbonate released from lactate metabolism promoted MnCO3 formation and that Mn(II) mineralogy was strongly affected by carbonate ions even in the presence of abundant sulfide and weakly alkaline conditions expected to favour the precipitation of MnS. Formation of MnS, as determined by a combination of micro-XRD, transmission electron microscopy, energy dispersive X-ray spectroscopy, and selected area electron diffraction analyses was consistent with equilibrium speciation modelling predictions. Biogenic manganese sulfide may be a manganese sink in the Mn biogeochemical cycle in select environments such as deep anoxic marine basins within the Baltic Sea.