Geobacter uraniireducens
Species of bacterium capable of reducing uranium
From Wikipedia, the free encyclopedia
Geobacter uraniireducens (more recently known as Geotalea uraniireducens[4]) is a gram-negative, rod-shaped, anaerobic, chemolithotrophic,[5] mesophilic, and motile bacterium from the genus of Geobacter.[1][2][6][7] G. uraniireducens has been found to reduce iron and uranium[8][7][5] in sediment and soil.[5] It is being studied for use in bioremediation projects due to its ability to reduce uranium and arsenic.[9][10][11][12]
| Geobacter uraniireducens | |
|---|---|
Scientific classification  | |
| Domain: | Bacteria |
| Kingdom: | Pseudomonadati |
| Phylum: | Thermodesulfobacteriota |
| Class: | Desulfuromonadia |
| Order: | Geobacterales |
| Family: | Geobacteraceae |
| Genus: | Geobacter |
| Species: | G. uraniireducens |
| Binomial name | |
| Geobacter uraniireducens | |
| Type strain[3] | |
| ATCC BAA-1134, JCM 13001, Rf4 | |
| Synonyms | |
|
Geotalea uraniireducens (Shelobolina et al. 2008) Waite et al. 2020 | |
History
Geobacter uraniireducens was isolated from the subsurface sediment of a previous uranium ore processing facility undergoing uranium bioremediation in 2002.[11] This occurred during a field study by Robert Anderson and his associates at the Old Rifle in situ test plot area in Rifle, Colorado.[11] Shelobolina et al. (2008) further described the strain Rf4T[7] While Geobacter uraniireducens is the basonym, David Waite and associates reclassified it to the current preferred name, Geotalea uraniireducens in their 2020 paper.[4]
Characteristics
Geobacter uraniireducens are gram negative bacteria that are motile rods with rounded ends and two to four long lateral flagellum, as well as pili and vesicles.[7]
Extracellular electron transport strategies
The strategy of G. uraniireducens for extracellular electron transport (EET) is to facilitate iron (Fe(III)) oxide reduction via the production of a soluble electron shuttle.[13] It has been found that riboflavin mediates EET to reduce extracellular electron acceptors.[14] This is important because unlike in most Geobacter species, where conductive pili are critical for effective reduction of extracellular electron acceptors, the pili of G. uraniireducens are not conductive.[14]
Metabolic mechanisms
Geobacter uraniireducens is an iron-reducing bacteria that uses acetate as an electron donor and reduces uranium (U(VI)).[7] In addition to Fe(III), it is also able to use Mn(IV), anthraquinone-2,6-disulfonate, malate and fumarate as electron acceptors.[7] As it uses Fe(III) oxide as the electron acceptor, it can oxidize acetate, lactate, pyruvate and ethanol as electron donors.[7]
Applications
Bioremediation
Geobacter uraniireducens have been used in bioremediation studies in situ to decontaminate groundwater containing high levels of uranium from previous activities.[9][10][11] This process can be enhanced by using acetate to stimulate increased populations.[11]
Environmental implications
One environmental implication of interest in G. uraniireducens is its arsenic (As(V)) reducing capabilities in subsurface sediments.[12] This ability is proposed to be due to gene encoding for respiratory arsenate reductase.[12]