Geobacter soli sp. nov., a dissimilatory Fe(III)-reducing bacterium isolated from forest soil

A novel Fe(III)-reducing bacterium, designated GSS01 T , was isolated from a forest soil sample using a liquid medium containing acetate and ferrihydrite as electron donor and electron acceptor, respectively. Cells of strain GSS01 T were strictly anaerobic, Gram-stain-negative, motile, non-spore-forming and slightly curved rod-shaped. Growth occurred at 16–40 °C and optimally at 30 °C. The DNA G+C content was 60.9 mol%. The major respiratory quinone was MK-8. The major fatty acids were C 16 : 0 , C 18 : 0 and C 16 : 1 ω7 c /C 16 : 1 ω6 c . Strain GSS01 T was able to grow with ferrihydrite, Fe(III) citrate, Mn(IV), sulfur, nitrate or anthraquinone-2,6-disulfonate, but not with fumarate, as sole electron acceptor when acetate was the sole electron donor. The isolate was able to utilize acetate, ethanol, glucose, lactate, butyrate, pyruvate, benzoate, benzaldehyde, m -cresol and phenol but not toluene, p -cresol, propionate, malate or succinate as sole electron donor when ferrihydrite was the sole electron acceptor. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain GSS01 T was most closely related to Geobacter sulfurreducens PCA T (98.3 % sequence similarity) and exhibited low similarities (94.9–91.8 %) to the type strains of other species of the genus Geobacter . The DNA–DNA relatedness between strain GSS01 T and G. sulfurreducens PCA T was 41.4±1.1 %. On the basis of phylogenetic analysis, phenotypic characterization and physiological tests, strain GSS01 T is believed to represent a novel species of the genus Geobacter , and the name Geobacter soli sp. nov. is proposed. The type strain is GSS01 T ( = KCTC 4545 T = MCCC 1K00269 T ).