Date of Award
Master of Science
Geological and Environmental Sciences
Dr. Johnson R. Haas
Dr. Carla M. Koretsky
Dr. Alan E. Kehew
Masters Thesis-Open Access
Haas and DiChristina (2002) have demonstrated that Fe(III) reduction by the facultative Fe(III)-reducing bacterium S. putrefaciens is mediated by competitive speciation among dissolved organic ligands and functional groups on the cell surface. They also showed that rates of Fe(III) reduction by S. putrefaciens correlate with the thermodynamic stability constants of the Fe(III)-organic ligand complexes. S. putrefaciens can also use U(VI) as a terminal electron acceptor, coupling U(VI) reduction to growth. In this study, S. putrefaciens was incubated in experimental media containing U(VI) in the form of aqueous complexes with a variety of organic ligands that differ significantly in structure and stability with respect to U(VI) chelation. Rates of U(VI) reduction by S. putrefaciens vary strongly as a function of U(VI) aqueous speciation. The results of this study indicate that U(VI) reduction under field conditions may be inhibited by the presence of organic chelating ligands.
Northup, Abraham M., "Competitive Effects of Uranyl-Organic Complexes on U(VI) Reduction by Shewanella putrefaciens" (2006). Masters Theses. 1414.