Geobacter uraniireducens was isolated from the subsurface sediment of a previous uranium ore processing facility undergoing uranium bioremediation in 2002.[12] This occurred during a field study by Robert Anderson and his associates at the Old Rifle in situ test plot area in Rifle, Colorado.[12] 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
G. 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.[14] It has been found that riboflavin mediates EET to reduce extracellular electron acceptors.[15] 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.[15]
Metabolic mechanisms
G. 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
G. uraniireducens have been used in bioremediation studies in situ to decontaminategroundwater containing high levels of uranium from previous activities.[10][11][12] This process can be enhanced by using acetate to stimulate increased populations.[12]
Environmental implications
One environmental implication of interest in G. uraniireducens is its arsenic (As(V)) reducing capabilities in subsurface sediments.[13] This ability is proposed to be due to gene encoding for respiratory arsenate reductase.[13]
^Parker, Charles Thomas; Wigley, Sarah; Garrity, George M (2009). Parker, Charles Thomas; Garrity, George M (eds.). "Nomenclature Abstract for Geobacter uraniireducens Shelobolina et al. 2008". The NamesforLife Abstracts. doi:10.1601/nm.13330.
