HR: 17:45h
AN: B24D-08    [Abstracts]
TI: Secondary Iron Mineral Formation by Shewanellae Using Different Carbon Sources
AU: * Salas, E C
EM: everetts@usc.edu
AF: University of Southern California, Zumberge Hall of Science 3651 Trousdale Parkway, Los Angeles, CA 90089, United States
AU: Kukkadapu, R K
EM: Ravi.Kukkadapu@pnl.gov
AF: Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, United States
AU: Fredrickson, J K
EM: Jim.Fredrickson@pnl.gov
AF: Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99352, United States
AU: Nealson, K H
EM: knealson@usc.edu
AF: University of Southern California, Zumberge Hall of Science 3651 Trousdale Parkway, Los Angeles, CA 90089, United States
AB: It has been known for some time that microbes play an important role in the redox cycling of iron. A considerable amount of work has been done investigating the various factors that play a role in solid phase iron reduction such as the type of iron oxide available for reduction, medium composition, surface area and ferrous iron concentration. However, the rate at which a single cell reduces iron oxides and the impact of dissimilatory iron reduction kinetics on mineral speciation are not well understood. In order to determine the relationship between iron oxide reduction rates and secondary mineral formation, we have tested 4 different strains of Shewanella with different carbon sources. Strains MR-1, MR-4, CN32 and W3-18-1 were incubated with HFO (hydrous ferric oxide) as electron acceptor and either lactate, pyruvate, isoleucine or uridine as the organic carbon source. Mineral products were analyzed using X-ray diffraction, electron microscopy and Mossbauer spectroscopy. Initial results suggest that reduction rates are similar among strains when using the same carbon source. However, qualitative assessment of mineral products suggests that while reduction rates for the tested strains may be similar, the secondary mineral products can be quite different.
DE: 0419 Biomineralization
DE: 0448 Geomicrobiology
DE: 0461 Metals
DE: 0463 Microbe/mineral interactions
DE: 0465 Microbiology: ecology, physiology and genomics (4840)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting