Geobacter uraniireducens sp. nov., isolated from subsurface sediment undergoing uranium bioremediation

1 Department of Microbiology, University of Massachusetts, Morrill Science Center IVN, Amherst, MA 01003, USA 2 Department of Biological Sciences, University of Alabama, Box 870206, Tuscaloosa, AL 35487-0206, USA Correspondence Evgenya S. Shelobolina shelobolina{at}wisc.edu A Gram-negative, rod-shaped, motile bacterium, strain Rf4 T , which conserves energy from dissimilatory Fe(III) reduction concomitant with acetate oxidation, was isolated from subsurface sediment undergoing uranium bioremediation. The 16S rRNA gene sequence of strain Rf4 T matched sequences recovered in 16S rRNA gene clone libraries constructed from DNA extracted from groundwater sampled at the same time as the source sediment. Cells of strain Rf4 T were regular, motile rods, 1.2–2.0 µm long and 0.5–0.6 µm in diameter, with rounded ends. Cells had one lateral flagellum. Growth was optimal at pH 6.5–7.0 and 32 °C. With acetate as the electron donor, strain Rf4 T used Fe(III), Mn(IV), anthraquinone-2,6-disulfonate, malate and fumarate as electron acceptors and reduced U(VI) in cell suspensions. With poorly crystalline Fe(III) oxide as the electron acceptor, strain Rf4 T oxidized the following electron donors: acetate, lactate, pyruvate and ethanol. Phylogenetic analysis of the 16S rRNA gene sequence of strain Rf4 T placed it in the genus Geobacter . Strain Rf4 T was most closely related to ‘ Geobacter humireducens ’ JW3 (95.9 % sequence similarity), Geobacter bremensis Dfr1 T (95.4 %) and Geobacter bemidjiensis Bem T (95.1 %). Based on phylogenetic analysis and phenotypic differences between strain Rf4 T and closely related Geobacter species, this strain is described as a representative of a novel species, Geobacter uraniireducens sp. nov. The type strain is Rf4 T (=ATCC BAA-1134 T =JCM 13001 T ). Abbreviations: AQDS, anthraquinone-2,6-disulfonate; DIRB, dissimilatory iron-reducing bacteria Present address: Department of Geology and Geophysics, University of Wisconsin–Madison, 1215 W. Dayton St. A362, Madison, WI 53706, USA. The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of Geobacter uraniireducens strain Rf4 T is EF527427 .