Thrust 4: Model Hematite Thin Films and Bacterial Iron Reduction (LDRD: Cytochrome and Whole Cell Interactions with Iron Oxides)
EMSL Project ID
13492
Abstract
This LDRD project is the fourth one associated with the Biogeochemistry Grand Challenge (BGC). Its overall goal is to develop new capabilities and materials as needed to understand the molecular scale biogeochemistry associated with electron transfer at the organism-mineral interface. Two primary activities will be pursued to accomplish this goal. First, new applications of scanning probe microscopy will be developed to characterize the nanometer-scale spatial location of cytochromes on bacterial surfaces, to quantify the interaction forces between purified recombinant cytochromes and mineral surfaces and between individual cytochromes and other proteins in complexes, and to measure integrated adhesion forces between whole organisms and mineral surfaces of known structure. Second, new model oxide experimental materials will be developed (both synthetic and natural) that can be used to study the molecular biogeochemistry of bacterial iron reduction, and new surface science preparation methods will be developed to allow the imaging of surface structure and Fe valence beneath single microorganisms, bacterial colonies, and/or biofilms with state-of-the-art instrumental techniques. These capabilities are essential to the successful completion of the BGC. The proposed activity will develop and characterize model thin film Fe(III) oxide systems using natural and MBE hematite suitable for analysis using both synchrotron-based spectroscopies and TEM (transmission electron microscopy; after backside thinning). Initial measurements of the effects of Shewanella metabolism on the surface structure, morphology, and electronic properties of doped and undoped hematite and the influence of these properties on the electron transfer reaction will be evaluated. The initial measurements of the effects of Shewanella metabolism on thin film hematites will demonstrate the utility of the model system and provide a platform for further molecular studies of the microbe-mineral interface.
Project Details
Project type
Grand Challenge
Start Date
2005-02-15
End Date
2008-03-24
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members