Geoalkalibacter subterraneus

This student page has not been curated.

Classification

Higher order taxa

Bacteria; Proteobacteria; Deltaproteobacteria; Desulfuromonadales; Geobacteraceae

Species

Geoalkalibacter subterraneus

Description and Significance

Geoalkalibacter subterraneus is a gram-negative motile rod with polar flagella. G. subterraneus does not form spores. cells range in length 1.0-5.0µm, and diameter .5-.6µm.

Electron micrograph of strain Red1^T showing the short rod shape and flagella (arrow). Bar, 0.2 μm.

Genome Structure

Geoalkalibacter subterraneus has one circular chromosome and one plasmid, both have been completely sequenced for strain Red1^T[1] The chromosome contains 3.48Mb, 3287 genes and 3202 coding genes with 57.0%GC. The plasmid contains 242Kb, 258 genes and 256 coding genes with 51.4% GC.

Cell Structure, Metabolism and Life Cycle

G. subterraneus is strictly anaerobic. It obtains energy by reducing a variety of oxidized species including Fe(III), Mn(IV), nitrate, elemental sulfur and trimethylamine N-oxide; in the presence of a wide range of electron donors including; acetate, butyrate, isobutyrate, citrate, decanoate, dodecanoate, ethanol, formate, fumarate, glycerol, hydrogenlactate, malonate, methanol, octanoate, palmitate, p-anisate, peptone, propionate, pyruvate, salicylate, stearate, succinate, valerate, isovalerate and yeast extract. G. subterraneus grows optimally at 40°C, pH 7 and salinity 20g/L. G. subterraneus can grow between temperatures 30-50°C, salinity between 1-100g/L, and pH 6-9.

Ecology

Representative strain Red1^T was isolated from Redwash oilfield Utah, USA at a depth of 1540 m at 52 °C. The salinity level was measured to be 25 g/L with pH of 7.9. Unlike close relatives, G. subterraneus has a maximum growth rate close to pH 7, which is unusual for the Geoalkalibacter genus which are mostly alkaliphilic. It is unknown whether or not G. subterraneus is indigenous to oil reservoirs. It is likely that the strain was introduced to Redwash oilfield through the water flooding process[2] during secondary recovery, as the closest relatives to G. subterraneus are endemic to rivers, and Redwash oilfield was specifically flooded with river water.

References

Greene, A., Patel, B., and Yacob, S. "Geoalkalibacter subterraneus sp. nov., an anaerobic Fe(III) and Mn(IV) reducing bacterium from a petroleum reservoir, and emended descriptions of the family Desulfuromonadaceae and the genus Geoalkalibacter." International Journal of Systematic and Evolutionary Microbiology. 2009. Volume 59. p. 781–785.

Carmona-Martínez, A., Pierra, M., Trably, E., and Bernet, N. "High current density via direct electron transfer by the halophilic anode respiring bacterium Geoalkalibacter subterraneus." Physical Chemistry Chemical Physics. 2013. Volume 15. p. 19699-19707.

Author

Page authored by Luke Pryke and Hannah Pak, students of Prof. Jay Lennon at Indiana University.