Abstract/Details

The significance of iron(III) reducing bacteria in uranium(VI) bioremediation and energy production by sediment fuel cells


2003 2003

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Abstract (summary)

Dissimilatory Fe(III) reduction is one of the most significant metabolisms in sedimentary environments. Molecular and geochemical studies conducted on uranium contaminated sediments suggested that Fe(III) reducing bacteria could be stimulated to reduce U(VI) in uranium contaminated subsurface sediments. This is particularly significant because U(VI) is highly soluble, and therefore mobile, in most groundwaters whereas the reduced form of uranium, U(IV), is generally insoluble and precipitates from most groundwaters. Therefore, stimulating microbial reduction of U(VI) could potentially stop the spread of uranium contamination in the subsurface and, if the bioremediation process is engineered properly, concentrate uranium into a discrete zone for subsequent recovery. The anaerobic electrode of sediment fuel cells is another sedimentary environment where dissimilatory Fe(III) reducing bacteria predominate. Molecular and culturing studies have shown that dissimilatory Fe(III) reducing microorganisms are directly involved in electricity production by sediment fuel cells. These findings should help with the development and optimization of several environmentally relevant tools; i.e. microbial fuel cells that convert waste to useable energy forms. Further evaluation of the dissimilatory Fe(III) reducing microbial communities associated with these two important sedimentary environments suggested that a specific group of organisms, the Geobacteraceae, are primarily responsible for uranium removal from subsurface sediments and electron transfer to an electrode. In fact, two organisms, strains A1 and A2, were recovered from the surface of an electrode and are able to quantitatively transfer electrons available from the complete oxidation of organic acids to an electrode surface. A detailed evaluation of pure cultures of Geobaceraceae species indicated that the Geobacteraceae are a phylogenetically and physiologically distinct family within the δ-subdivision of Proteobacteria. This unique physiology may allow Geobacteraceae species to be most competitive in these sedimentary environments. Another family of dissimilatory metal reducing microorganisms, the Desulfobulbaceae, were also found to be associated with the current-harvesting anodes of marine sediment fuel cells. Further evaluation of a member of this family, Desulfobulbus propionicus, indicated that this organism is also capable of dissimilatory Fe(III) reduction and is able to directly transfer electrons to an electrode. Thus, Desulfobulbaceae species may also contribute to energy production in marine sediment fuel cells.

Indexing (details)


Subject
Microbiology;
Environmental engineering
Classification
0410: Microbiology
0775: Environmental engineering
Identifier / keyword
Applied sciences; Biological sciences; Bioremediation; Dissimilatory iron-reducing bacteria; Energy production; Sediment fuel cells; Uranium
Title
The significance of iron(III) reducing bacteria in uranium(VI) bioremediation and energy production by sediment fuel cells
Author
Holmes, Dawn Elena
Number of pages
234
Publication year
2003
Degree date
2003
School code
0118
Source
DAI-B 64/06, Dissertation Abstracts International
Place of publication
Ann Arbor
Country of publication
United States
Advisor
Lovley, Derek R.
University/institution
University of Massachusetts Amherst
University location
United States -- Massachusetts
Degree
Ph.D.
Source type
Dissertations & Theses
Language
English
Document type
Dissertation/Thesis
Dissertation/thesis number
3096283
ProQuest document ID
305321886
Copyright
Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.
Document URL
http://search.proquest.com/docview/305321886
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