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Thermotoga elfii
Thermotoga elfii is a rod-shaped, glucose-fermenting bacterium. The type strain of T. elfii is SEBR 6459T.[1] The genus Thermotoga was originally thought to be strictly found surrounding submarine hydrothermal vents, but this organism was subsequently isolated in African oil wells in 1995.[1] A protective outer sheath allows this microbe to be thermophilic.[1] This organism cannot function in the presence of oxygen making it strictly anaerobic.[1] Some research proposes that the thiosulfate-reducing qualities in this organism could lead to decreased bio-corrosion in oil equipment in industrial settings.[2] HistoryDiscoveryThe genus Thermotoga, previously thought only to be found around submarine hydrothermal vents, was discovered in North Sea oil wells.[1] Due to this discovery, other wells in the area began being investigated, leading to the discovery of Thermotoga elfii in African oil wells in April 1995.[1] T. elfii was gathered in a one-liter sample at the head of a well at 68 °C.[1] Ravot et al. isolated this species by cultivation on a basal medium containing numerous different nutrients and resources (water, salt, glucose, sodium acetate, etc.) in the lab and then by using repeated trials of the agar shake dilution technique.[1] These scientists concluded by determining the samples' purity through microscopy.[1] TaxonomyThe first name of Thermotoga elfii is derived from the Greek root "therm," which means heat.[3] "Toga," which is a Roman term for an outer garment, is where the second part of the genus name originated.[3] This is due to the outer sheath that wraps around the bacteria to protect it from the extreme temperature often associated with this thermophile.[1] The latter name is derived from Elf-Aquitaine, the French oil company that owned the oil wells where T. elfii was first discovered.[1] Physiology and metabolismTherotoga elfii colonies of 1 millimeter have been observed in a laboratory setting, but the actual structure of the rod-shaped T. elfii is between 0.5-3 micrometers long.[1] Its protective outer sheath is the defining characteristic, which aided in providing T. elfii its name.[1] This structure balloons over each side of the organism and protects it from extreme heat.[1] When a Gram stain is performed on this organism, a gram-negative result is expected.[1] T. elfii has flagella uniformly distributed around its body, making it a peritrichous bacteria.[1] It is also an obligate anaerobe, meaning it cannot tolerate oxygen.[1] Electron acceptors include thiosulfate, arabinose, bio-trypticase, fructose, glucose, lactose, maltose, ribose, sucrose, and xylose.[1] Electron donors include acetate, carbon dioxide, and hydrogen.[1] Genome and phylogenyThe 16s RNA gene is 1,519 bases long with a GC content of 39.6 mol%.[1] Due to T. elfii’s relatively new status, much information about the number of genes is still unknown.[1] However, a 91.9% relative of this species, Thermotoga maritima, has been documented as having 1.86 million base pairs with 1,877 predicted coding regions.[4] The phylogenic family for Thermotoga elfii contains organisms such as Thermotoga thermarum, Thermotoga maritima, and Thermosipho africanus, which have a roughly 90% relation to this organism.[1] EcologyThe genus Thermotoga contains some of the most thermophilic microorganisms known.[5] It is composed of species that are thermophilic and hyperthermophilic which can thrive in temperatures as high as 80 °C.[5] The optimum growth temperature for Thermotoga elfii, however, is 66 °C.[1] The optimum pH is 7.5 and the optimum salinity is 1.2%.[1] ApplicationsIndustrial applicationsThe discovery of T. elfii has been deemed significant as it has led to other discoveries of methanogens, thermophiles, and sulfate-reducing bacteria.[1] This organism and the others discovered in this unique environment can help make progress in microbe-assisted oil recovery processes.[6] Thiosulfate, often implicated in the corrosion of metals used in oil pipelines, is reduced to sulfide by Thermotoga elfii, which leads many scientists to believe it has a major role in preserving oil extraction equipment.[1][6][2] Environmental applicationsIn many anoxic thermal marine hot springs, thiosulfate oxidation often does not occur or occurs at an extremely slow rate.[2] These thermophilic thiosulfate-reducers can play a key role in the mineralization of organic compounds to simpler, plant-accessible forms.[2] References
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