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Thermoanaerobacter
About: Thermoanaerobacter is a research topic. Over the lifetime, 232 publications have been published within this topic receiving 6934 citations.
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TL;DR: The hypothesis that sulfur-utilizing and methane-producing thermophilic microorganisms have a widespread distribution in oil reservoirs and the potential to actively participate in the biogeochemical transformation of carbon, hydrogen, and sulfur in situ is strongly supported.
Abstract: Recent investigations of oil reservoirs in a variety of locales have indicated that these habitats may harbor active thermophilic prokaryotic assemblages. In this study, we used both molecular and culture-based methods to characterize prokaryotic consortia associated with high-temperature, sulfur-rich oil reservoirs in California. Enrichment cultures designed for anaerobic thermophiles, both autotrophic and heterotrophic, were successful at temperatures ranging from 60 to 90°C. Heterotrophic enrichments from all sites yielded sheathed rods (Thermotogales), pleomorphic rods resembling Thermoanaerobacter, and Thermococcus-like isolates. The predominant autotrophic microorganisms recovered from inorganic enrichments using H2, acetate, and CO2 as energy and carbon sources were methanogens, including isolates closely related to Methanobacterium, Methanococcus, and Methanoculleus species. Two 16S rRNA gene (rDNA) libraries were generated from total community DNA collected from production wellheads, using either archaeal or universal oligonucleotide primer sets. Sequence analysis of the universal library indicated that a large percentage of clones were highly similar to known bacterial and archaeal isolates recovered from similar habitats. Represented genera in rDNA clone libraries included Thermoanaerobacter, Thermococcus, Desulfothiovibrio, Aminobacterium, Acidaminococcus, Pseudomonas, Halomonas, Acinetobacter, Sphingomonas, Methylobacterium, and Desulfomicrobium. The archaeal library was dominated by methanogen-like rDNAs, with a lower percentage of clones belonging to the Thermococcales. Our results strongly support the hypothesis that sulfur-utilizing and methane-producing thermophilic microorganisms have a widespread distribution in oil reservoirs and the potential to actively participate in the biogeochemical transformation of carbon, hydrogen, and sulfur in situ.
481 citations
TL;DR: Two strains, JW 200 and JW 201, of an extreme thermophilic, non-spore-forming anaerobic bacterium were isolated from alkaline and slightly acidic hot springs located in Yellowstone National Park and the name Thermoanaerobacter ethanolicus gen. nov.
Abstract: Two strains, JW 200 and JW 201, of an extreme thermophilic, non-spore-forming anaerobic bacterium were isolated from alkaline and slightly acidic hot springs located in Yellowstone National Park. Both strains were peritrichously flagellated rods. Cell size varied from 0.5–0.8 by 4–100 μm; coccoid-shaped cells of about 1 μm in diameter frequently occurred. Division was often unequal. Spheroplast-like forms were visible at the late logarithmic growth phase. The Gram reaction was variable. The DNA base composition of the two strains was between 37 and 39 mol% guanine plus cytosine as determined by buoyant density measurements and approximately 32% by the thermal denaturation method. The main fermentation products from hexoses were ethanol and CO2. Growth occurred between 37 and 78°C and from pH 4.4 to 9.8. The name Thermoanaerobacter ethanolicus gen. nov., spec. nov. was proposed for the two, new isolates. Strain JW 200 was designated as the type strain.
273 citations
TL;DR: Two thermophilic, anaerobic, xylan-degrading bacteria, strains B6A-RIT (T = type strain) and LX-11T, were isolated from Frying Pan Springs in Yellowstone National Park as discussed by the authors.
Abstract: Two thermophilic, anaerobic, xylan-degrading bacteria, strains B6A-RIT (T = type strain) and LX-11T, were isolated from Frying Pan Springs in Yellowstone National Park. These organisms grew chemoorganotrophically by utilizing xylan and starch but not cellulose, as well as a number of di- and monosaccharides, including glucose and xylose. Both organisms had the same optimum temperature and pH for growth (60°C and pH 6.0). The fermentation products included acetate, ethanol, lactate, CO2, and H2. Both organisms were rod shaped and deposited sulfur on their cells. The major difference between the two isolates was in spore formation; strain LX-11T sporulated, whereas strain B6A-RIT were compared with other thermophilic, anaerobic, xylan-degrading bacteria by performing DNA-DNA hybridizations and total protein analyses in order to determine the relationships of these organisms. Three different groups were identified, and new taxonomic assignments are proposed. Clostridium thermocellum LQRI was least closely related to the other seven strains studied and is placed in group I, retaining its original taxonomic assignment. Clostridium thermosulfurogenes 4BT and new isolates B6A-RIT are closely related and fall into group II, for which the new genus Thermoanaerobacterium is proposed. Isolate LX-11T is designated Thermoanaerobacterium xylanolyticum sp. nov., and isolate B6A-RIT is designated Thermoanaerobacterium saccharolyticum sp. nov. Thermoanaerobacterium thermosulfurigenes 4BT (originally C. thermosulfurogenes) is the type strain of the type species of the genus. Group III strains are placed in the genus Thermoanaerobacter; this group includes Thermoanaerobacter ethanolicus JW200T, Clostridium thermohydrosulfuricum 39E and E100-69T, and Thermoanaerobium brockii HTD4T. Thermoanaerobium brockii HTD4T is renamed Thermoanaerobacter thermohydrosulfuricus comb. nov. C. thermohydrosulfuricum 39E is nearly identical to Thermoanaerobacter ethanolicus JW200T, and these organisms are considered members of the same species. Therefore, C. thermohydrosulfuricum 39E is renamed Thermoanaerobacter ethanolicus 39E; strain JW200 is the type strain of Thermoanaerobacter ethanolicus.
216 citations
TL;DR: The results reported here, with sequence-related proteins from prokaryotes but in the same family as the sGC heme domain, show that these proteins have evolved to discriminate between ligands such as NO and O2; hence, this family H-NOX domains (heme-nitric oxide/oxygen).
Abstract: Soluble guanylate cyclase (sGC) is a nitric oxide- (NO-) sensing hemoprotein that has been found in eukaryotes from Drosophila to humans. Prokaryotic proteins with significant homology to the heme domain of sGC have recently been identified through genomic analysis. Characterization of two of these proteins is reported here. The first is a 181 amino acid protein cloned from Vibrio cholerae (VCA0720) that is encoded in a histidine kinase-containing operon. The ferrous unligated form of VCA0720 is 5-coordinate, high-spin. The CO complex is low-spin, 6-coordinate, and the NO complex is high-spin and 5-coordinate. These ligand-binding properties are very similar to those of sGC. The second protein is the N-terminal 188 amino acids of Tar4 (TtTar4H), a predicted methyl-accepting chemotaxis protein (MCP) from the strict anaerobe Thermoanaerobacter tengcongensis. TtTar4H forms a low-spin, 6-coordinate ferrous−oxy complex, the first of this sGC-related family that binds O2. TtTar4H has ligand-binding properties s...
176 citations
TL;DR: A unique combination of hydrogenases, a ferredoxin-dependent [NiFe] hydrogenase and an NADH-dependent Fe-only hydrogenase, were found to be responsible for H(2) formation in this organism.
Abstract: Thermoanaerobacter tengcongensis is a thermophilic Gram-positive bacterium able to dispose of the reducing equivalents generated during the fermentation of glucose to acetate and CO2 by reducing H+ to H2. A unique combination of hydrogenases, a ferredoxin-dependent [NiFe] hydrogenase and an NADH-dependent Fe-only hydrogenase, were found to be responsible for H2 formation in this organism. Both enzymes were purified and characterized. The tightly membrane-bound [NiFe] hydrogenase belongs to a small group of complex-I-related [NiFe] hydrogenases and has highest sequence similarity to energy-converting [NiFe] hydrogenase (Ech) from Methanosarcina barkeri. A ferredoxin isolated from Ta. tengcongensis was identified as the physiological substrate of this enzyme. The heterotetrameric Fe-only hydrogenase was isolated from the soluble fraction. It contained FMN and multiple iron–sulfur clusters, and exhibited a typical H-cluster EPR signal after autooxidation. Sequence analysis predicted and kinetic studies confirmed that the enzyme is an NAD(H)-dependent Fe-only hydrogenase. When H2 was allowed to accumulate in the culture, the fermentation was partially shifted to ethanol production. In cells grown at high hydrogen partial pressure [p(H2)] the NADH-dependent hydrogenase activity was fourfold lower than in cells grown at low p(H2), whereas aldehyde dehydrogenase and alcohol dehydrogenase activities were higher in cells grown at elevated p(H2). These results indicate a regulation in response to the p(H2).
171 citations