Understanding Microorganism-Metal Interactions
EMSL Project ID
26703
Abstract
This is a general access capabilities-based proposal, requesting standard access to EMSL Transmission and Scanning Electron Micrographs to acquire non-proprietary data. The proposed research aims to elucidate the roles microorganisms play in cycling of metals in acid mine drainage (AMD). Specifically, we want to characterize the result of aqueous Cu (Cuaq) interacting with Acidithiobacillus ferrooxidans, an Fe- and S-oxidizing Proteobacterium found in some AMD environments. Copper is chosen because of its relatively large isotopic variation in nature and affinity for biological/organic materials. Previous experiments show that Cu associated with whole A. ferrooxidans cells grown in Cu-rich medium is isotopically enriched in 65Cu (based on 65Cu/63Cu) relative to Cuaq. Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectroscopy (EDXS) showed Fe- and Cu-rich areas (presumed to be Fe-Cu oxide precipitates) on the outer membrane of these cells. The samples were chemically fixed prior to TEM, so Cu phases associated with the cells could have been altered, however. We request the use of EMSL's TEM and SEM with EDXS to provide further information about Cuaq-A. ferrooxidans interactions. TEM and SEM analysis of cells will allow us to detect morphological differences between cells grown with and without the presence of Cu, and EDXS will locate Cu-rich areas within or surrounding the cell. Cryofixation prior to analysis is preferred, as it may better preserve the integrity of the cell and the cell-metal interface. Results acquired at EMSL will complement further Cu isotope fractionation experiments with A. ferrooxidans at Penn State. This research will determine the significance of biologically-induced metal attenuation in AMD, which is useful for remediation purposes.
Project Details
Project type
Capability Research
Start Date
2007-10-08
End Date
2009-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Kimball BE, R Mathur, A Dohnalkova, AJ Wall, RL Runkel, and SL Brantley. 2009. "Copper isotope fractionation in acid mine drainage." Geochimica et Cosmochimica Acta 73(5):1247-1263.