Geobacter sp. strain OR-1 genome sequencing. Geobacter sp. OR-1

Geobacter sp. OR-1 was isolated from arsenic-polluted paddy soil in Japan as a dissimilatory arsenate-reducing bacterium. It is phylogenetically closely related with Geobacter pelophilus with a 16S rRNA gene sequence similarity of 98.7%, and can also utilize soluble Fe(III), ferrihydrite, nitrate and fumarate as electron acceptors. Strain OR-1 can catalyze arsenic dissolution from arsenate-adsorbed ferrihydrite. In addition, inoculation of washed cells of strain OR-1 into sterilized paddy soil successfully restored arsenic release. Recently, elevated levels of arsenic in groundwater threaten the health of people worldwide, and the genus Geobacter has been believed to be involved in the arsenic release, probably through reductive dissolution of arsenic-bearing iron (hydr)oxides or direct reduction of arsenate adsorbed on iron (hydr)oxides. Thus, strain OR-1 may be useful as a model microorganism that potentially impacts the mobilization of arsenic in flooded soils and anoxic sediments.