Summary auto-generated
Researchers isolated a novel thermophilic bacterium, designated strain SEBR 6459T, from an African oil-producing well with an in situ temperature of 68°C and high salt concentration. The organism was identified as a member of the genus Thermotoga based on its characteristic outer sheath-like structure (toga), morphology, 16S rRNA gene sequences, and ability to ferment carbohydrates. The strain exhibits an optimum growth temperature of 66°C and can utilize glucose, arabinose, fructose, lactose, maltose, and xylose. It is strictly anaerobic with gram-negative cell wall ultrastructure and peritrichous flagella. Phylogenetic analysis based on 16S rRNA sequencing revealed significant differences from previously described Thermotoga species, with only 92% similarity to the closest relatives. Key distinguishing features include its lower optimal growth temperature compared to other Thermotoga species, unique sodium chloride tolerance range (0-2.8%), absence of lactate as a fermentation product, and different metabolic capabilities. The DNA G+C content is 39.6 mol%. Based on these morphological, physiological, and genetic differences, the authors propose this strain as a new species, Thermotoga elfii, named after Elf-Aquitaine, an oil company involved in the exploration work.
Key findings
- A novel thermophilic anaerobic bacterium (Thermotoga elfii) was isolated from an African oil well, representing a new species within the genus Thermotoga with 92% 16S rRNA similarity to closest relatives
- The organism has an optimum growth temperature of 66°C (lower than typical Thermotoga species at ~80°C) and sodium chloride tolerance of 0-2.8%, reflecting adaptation to oil field conditions
- Thermotoga elfii utilizes multiple carbohydrates in the presence of thiosulfate as an electron acceptor, producing acetate, CO2, and H2 as fermentation end products
- The strain possesses characteristic Thermotogales features including an outer toga structure, gram-negative cell wall, and peritrichous flagella, but differs significantly in physiological properties from other Thermotoga species
- The discovery of this sulfide-producing thermophile in oil fields raises questions about its role in biocorrosion processes, as thiosulfate (from sulfide oxidation) has been implicated in increasing corrosion risk
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
A thermophilic, glucose-fermenting, strictly anaerobic, rod-shaped bacterium, strain SEBR 6459T (T = type strain), was isolated from an African oil-producing well. This organism was identified as a member of the genus Thermotoga on the basis of the presence of the typical outer sheath-like structure (toga) and 16S rRNA signature sequences and its ability to grow on carbohydrates (glucose, arabinose, fructose, lactose, maltose, and xylose). Major differences in its 16S rRNA gene sequence, its lower optimum temperature for growth (66 degrees C), its sodium chloride range for growth (0 to 2.8%), its lack of lactate as an end product from glucose fermentation, and its peritrichous flagella indicate that strain SEBR 6459T is not similar to the three previously described Thermotoga species. Furthermore, this organism does not belong to any of the other genera related to the order Thermotogales that have been described. On the basis of these findings, we propose that this strain should be described as a new species, Thermotoga elfii. The type strain of T. elfii is SEBR 6459 (= DSM 9442).