Thermosediminibacter oceani gen. nov., sp. nov. and Thermosediminibacter litoriperuensis sp. nov., new anaerobic thermophilic bacteria isolated from Peru Margin

A new group of anaerobic thermophilic bacteria was isolated from enrichment cultures obtained from deep sea sediments of Peru Margin collected during Leg 201 of the Ocean Drilling Program. A total of ten isolates were obtained from cores of 1–2 m below seafloor (mbsf) incubated at 60°C: three isolates came from the sediment 426 m below sea level with a surface temperature of 9°C (Site 1227), one from 252 m below sea level with a temperature of 12°C (Site 1228), and six isolates under sulfate-reducing condition from the lower slope of the Peru Trench (Site 1230). Strain JW/IW-1228P from the Site 1228 and strain JW/YJL-1230-7/2 from the Site 1230 were chosen as representatives of the two identified clades. Based on the 16S rDNA sequence analysis, these isolates represent a novel group with Thermovenabulum and Caldanaerobacter as their closest relatives. The temperature range for growth was 52–76°C with an optimum at around 68°C for JW/IW-1228P and 43–76°C with an optimum at around 64°C for JW/YJL-1230-7/2. The pH^25C range for growth was from 6.3 to 9.3 with an optimum at 7.5 for JW/IW-1228P and from 5 to 9.5 with an optimum at 7.9–8.4 for JW/YJL-1230-7/2. The salinity range for growth was from 0% to 6% (w/v) for JW/IW-1228P and from 0% to 4.5% (w/v) for JW/YJL-1230-7/2. The G+C content of the DNA was 50 mol% for both JW/IW-1228P and JW/YJL-1230-7/2. DNA–DNA hybridization yielded 52% similarity between the two strains. According to 16S rRNA gene sequence analysis, the isolates are located within the family, Thermoanaerobacteriaceae. Based on their morphological and physiological properties and phylogenetic analysis, it is proposed that strain JW/IW-1228P^T is placed into a novel taxa, Thermosediminibacter oceani, gen. nov., sp. nov. (DSM 16646^T=ATCC BAA-1034^T), and JW/YJL-1230-7/2^T into Thermosediminibacter litoriperuensis sp. nov. (DSM 16647^T =ATCC BAA-1035^T).An erratum to this article can be found at     

Thermohydrogenium kirishiense gen. nov. and sp. nov., a new anaerobic thermophilic bacterium

Six strains of a new anaerobic thermophilic non-sporeforming bacterium were isolated in pure culture from industrial yeast biomass. Cells were rod-shaped (0.4–0.8×1.0–11.0 m), non-motile. They stained gram-negative, but outer membrane was not present. The growth occurred between 45–75 °C, the optimal temperature is 65°. Optimal pH value was 7.0–7.4. The bacterium utilized for growth several sugars, starch and yeast extract. The best source of nitrogen was peptone. The main fermentation products of glucose were ethanol, acetate, H₂ and CO₂. As minor products isopropanol, butanol, butyrate and lactate were found. Glucose was metabolized via the Embden-Meyerhoff pathway. Cytochromes and quinones were not found. DNA-base composition was 33.2–34.0 mol%. The DNA-DNA hybridization and 5S rRNA nucleotide sequences showed distantly related of isolated stains to phenotypical similar bacteria. It was proposed to consider the isolated bacterium as Thermohydrogenium kirishiense gen. nov. and sp. nov.     

Desulfovibrio oceani subsp. oceani sp. nov., subsp. nov. and Desulfovibrio oceani subsp. galateae subsp. nov., novel sulfate-reducing bacteria isolated from the oxygen minimum zone off the coast of Peru

Two deltaproteobacterial sulfate reducers, designated strain I.8.1^T and I.9.1^T, were isolated from the oxygen minimum zone water column off the coast of Peru at 400 and 500 m water depth. The strains were Gram-negative, vibrio-shaped and motile. Both strains were psychrotolerant, grew optimally at 20°C at pH 7.0–8.0 and at 2.5–3.5% NaCl (w/v). The strains grew by utilizing hydrogen/acetate, C_3–4 fatty acids, amino acids and glycerol as electron acceptors for sulfate reduction. Fumarate, lactate and pyruvate supported fermentative growth. Sulfate, sulfite, thiosulfate and taurin supported growth as electron acceptors. Both strains were catalase-positive and highly oxygen-tolerant, surviving 24 days of exposure to atmospheric concentrations. MK6 was the only respiratory quinone. The most prominent cellular fatty acid was iso-17:1-ω9c (18%) for strain I.8.1^T and iso-17:0-ω9c (14%) for strain I.9.1^T. The G+C contents of their genomic DNA were 45–46 mol%. Phylogenetic analysis of 16S rRNA and dsrAB gene sequences showed that both strains belong to the genus Desulfovibrio. Desulfovibrio acrylicus DSM 10141^T and Desulfovibrio marinisediminis JCM 14577^T represented their closest validly described relatives with pairwise 16S rRNA gene sequence identities of 98–99%. The level of DNA-DNA hybridization between strains I.8.1^T and I.9.1^T was 30–38%. The two strains shared 10–26% DNA-DNA relatedness with D. acrylicus. Based on a polyphasic investigation it is proposed that strains I.8.1^T and I.9.1^T represent a novel species for which the name Desulfovibrio oceani sp. nov. is proposed with the two subspecies D. oceani subsp. oceani (type strain, I.8.1^T = DSM 21390^T = JCM 15970^T) and D. oceani subsp. galateae (type strain, I.9.1^T = DSM 21391^T = JCM 15971^T).     

Sinanaerobacter chloroacetimidivorans gen. nov., sp. nov., an obligate anaerobic bacterium isolated from anaerobic sludge

An obligate anaerobic bacterial strain (BAD-6^T) capable of degrading acetochlor and butachlor was isolated from an anaerobic acetochlor-degrading reactor. Cells were Gram-stain positive, straight to gently curved rods with flagella. The major fermentation products in peptone-yeast broth were acetate and butyrate. The optimum temperature and pH for growth was 30 °C and 7.2–7.5, respectively. The major cellular fatty acids (>?10%) were C_14:0 FAME, C_16:0 FAME and cyc-9,10-C_19:0 DMA. Genome sequencing revealed a genome size of 4.80 Mb, a G?+?C content of 43.6 mol% and 4741 protein-coding genes. The most closely related described species on the basis of 16S rRNA gene sequences was Anaerovorax odorimutans NorPut^T in the order Clostridiales of the class Clostridia with sequence similarity of 94.9%. The nucleotide identity (ANI) value and digital DNA–DNA hybridization (dDDH) between the genomes of strain BAD-6^T and Ana. odorimutans NorPut^T were 70.9% and 15.9%, respectively. Based on the distinct differences in phylogenetic and phenotypic characteristics between strain BAD-6^T and related species, Sinanaerobacter chloroacetimidivorans gen. nov., sp. nov. is proposed to accommodate the strain. Strain BAD-6^T is the type strain (=?CCTCC AB 2021092^T?=?KCTC 25290^T).

     

Thermohalobaculum xanthum gen. nov., sp. nov., a moderately thermophilic bacterium isolated from mangrove sediment

Antonie van Leeuwenhoek - A novel moderately thermophilic and halophilic bacterium, designated strain M0105T, was isolated from mangrove sediment collected in the Beibu Gulf, south China. The...     

Sufflavibacter maritimus gen. nov., sp. nov., novel Flavobacteriaceae bacteria isolated from marine environments

Four Gram-negative, chemoheterotrophic, nonmotile, yellow-colored strains were isolated from the East Sea or from deep-sea sediments of Nankai Trough by standard dilution plating. Characterization by polyphasic approaches indicated that the four strains are members of the same species. Phylogenetic analyses based on 16S rRNA gene sequences revealed that the strains formed a coherent and novel genus-level lineage within the family Flavobacteriaceae. The dominant cellular fatty acids were i-C15:0, 3-OH i-C17:0, and 2-OH i-C15:0 and/or C16:1 omega7c. Predominance of 2-OH i-C 15:0 and/or C16:1omega7c clearly differentiated the strains from closely related members. The DNA G+C contents ranged 35.1-36.2 mol%. It is proposed, from the polyphasic evidence, that the strains should be placed into a novel genus and species named Sufflavibacter maritimus gen. nov., sp. nov., with strain IMCC 1001T (=KCCM 42359T=NBRC 102039T) as the type strain.     

Sedimenticola selenatireducens, gen. nov., sp. nov., an anaerobic selenate-respiring bacterium isolated from estuarine sediment

The respiration of selenate, as a terminal electron acceptor has been known for over a decade, but the microorganisms involved in this respiration are largely unknown. Here we characterize a novel selenate-respiring bacterium, strain AK4OH1, isolated from an estuarine sediment enrichment culture. Strain AK4OH1 has the unique capability to oxidize aromatic acids, such as benzoate, 4-hydroxybenzoate and 3-hydroxybenzoate, coupled to selenate respiration. This novel respiratory coupling has not been described before. Reduction of selenate is followed by stoichiometric accumulation of selenite. The strain grows in agar shake tubes forming bright red colonies due to precipitation of elemental selenium. Strain AK4OH1 is a strictly anaerobic bacterium, which can also respire nitrate and nitrite via denitrification. Analysis of the 16S rRNA gene sequence shows that this strain clusters with another selenate-reducing bacterium and a (per) chlorate reducing bacterium, within the Gammaproteobacteria, along with symbionts of bivalves and tubeworms. Based on its unique physiological capabilities and its 16S rRNA gene sequence phylogeny, we classify this strain AK4OH1 as a new genus and species with the proposed name Sedimenticola selenatireducens.     

Tepidibaculum saccharolyticum gen. nov., sp. nov. a moderately thermophilic,anaerobic, spore-forming bacterium isolated from a terrestrial hot spring

Extremophiles - A novel moderately thermophilic, anaerobic bacterium, strain STR9T was isolated from terrestrial hot spring at Uzon Caldera, Kamchatka peninsula, Russia. Cells of strain STR9T were...     

Thermoanaerobacter ethanolicus gen. nov., spec. nov., a new,extreme thermophilic,anaerobic bacterium

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 m; coccoid-shaped cells of about 1 m 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.A preliminary account of this work was presented at the annual meeting of the American Society for Microbiology, Los Angeles, CA, 1979 (J. Wiegel and L. G. Ljungdahl, Abstr. Annu. Meet. Am. Soc. Microbiol., 1979, 163, p. 105) and at the 27th IUPAC Congress Helsinki, 1979 (L. G. Ljungdahl and J. Wiegel, Abstracts p. 546)     

Desulforhabdus amnigenus gen. nov. sp. nov., a sulfate reducer isolated from anaerobic granular sludge

From granular sludge of an upflow anaerobic sludge bed (UASB) reactor treating paper-mill wastewater, a sulfate-reducing bacterium (strain ASRB1) was isolated with acetate as sole carbon and energy source. The bacterium was rod-shaped, (1.4–1.9×2.5–3.4 μm), nonmotile, and gram-negative. Optimum growth with acetate occurred around 37°C in freshwater medium (doubling time: 3.5–5.0 days). The bacterium grew on a range of organic acids, such as acetate, propionate, and butyrate, and on alcohols, and grew autotrophically with H₂, CO₂ and sulfate. Fastest growth occurred with formate, propionate, and ethanol (doubling time: approx. 1.5 days). Strain ASRB1 clusters with the delta subdivision of Proteobacteria and is closely related toSyntrophobacter wolinii a syntrophic propionate oxidizer. Strain ASRB1 was characterized as a new genus and species:Desulforhabdus amnigenus.     

Allobaculum stercoricanis gen. nov., sp. nov., isolated from canine feces

Morphological, biochemical, and molecular genetic studies were performed on an unknown anaerobic, catalase-negative, non-spore-forming, rod-shaped bacterium isolated from dog feces. The unknown bacterium was tentatively identified as a Eubacterium species, based on cellular morphological and biochemical tests. 16S rRNA gene sequencing studies, however, revealed that it was phylogenetically distant from Eubacterium limosum, the type species of the genus Eubacterium. Phylogenetically, the unknown species forms a hitherto unknown sub-line proximal to the base of a cluster of organisms (designated rRNA cluster XVI), which includes Clostridium innocuum, Streptococcus pleomorphus, and some Eubacterium species. Based on both phenotypic and phylogenetic criteria, it is proposed that the unknown bacterium be classified as a new genus and species, Allobaculum stercoricanis. Using a specific rRNA-targeted probe designed to identify Allobaculum stercoricanis, in situ hybridisation showed this novel species represents a significant organism in canine feces comprising between 0.1% and 3.7% of total cells stained with DAPI (21 dog fecal samples). The type strain of Allobaculum stercoricanis is DSM 13633(T)=CCUG 45212(T).     

Neoscardovia arbecensis gen. nov., sp. nov., isolated from porcine slurries

Three Gram-positive, anaerobic, pleomorphic strains (PG10(T), PG18 and PG22), were selected among five strains isolated from pig slurries while searching for host specific bifidobacteria to track the source of fecal pollution in water. Analysis of the 16S rRNA gene sequence showed a maximum identity of 94% to various species of the family Bifidobacteriaceae. However, phylogenetic analyses of 16S rRNA and HSP60 gene sequences revealed a closer relationship of these strains to members of the recently described Aeriscardovia, Parascardovia and Scardovia genera, than to other Bifidobacterium species. The names Neoscardovia gen. nov. and Neoscardovia arbecensis sp. nov. are proposed for a new genus and for the first species belonging to this genus, respectively, and for which PG10(T) (CECT 8111(T), DSM 25737(T)) was designated as the type strain. This new species should be placed in the Bifidobacteriaceae family within the class Actinobacteria, with Aeriscardovia aeriphila being the closest relative. The prevailing cellular fatty acids were C(16:0) and C(18:1)ω9c, and the major polar lipids consisted of a variety of glycolipids, diphosphatidyl glycerol, two unidentified phospholipids, and phosphatidyl glycerol. The peptidoglycan structure was A1γmeso-Dpm-direct. The GenBank accession numbers for the 16S rRNA gene and HSP60 gene sequences of strains PG10(T), PG18 and PG22 are JF519691, JF519693, JQ767128 and JQ767130, JQ767131, JQ767133, respectively.     

Motiliproteus sediminis gen. nov., sp. nov., isolated from coastal sediment

A novel Gram-stain-negative, rod-to-spiral-shaped, oxidase- and catalase- positive and facultatively aerobic bacterium, designated HS6^T, was isolated from marine sediment of Yellow Sea, China. It can reduce nitrate to nitrite and grow well in marine broth 2216 (MB, Hope Biol-Technology Co., Ltd) with an optimal temperature for growth of 30–33 °C (range 12–45 °C) and in the presence of 2–3 % (w/v) NaCl (range 0.5–7 %, w/v). The pH range for growth was pH 6.2–9.0, with an optimum at 6.5–7.0. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated that the novel isolate was 93.3 % similar to the type strain of Neptunomonas antarctica, 93.2 % to Neptunomonas japonicum and 93.1 % to Marinobacterium rhizophilum, the closest cultivated relatives. The polar lipid profile of the novel strain consisted of phosphatidylethanolamine, phosphatidylglycerol and some other unknown lipids. Major cellular fatty acids were summed feature 3 (C_16:1 ω7c/iso-C_15:0 2-OH), C_18:1 ω7c and C_16:0 and the main respiratory quinone was Q-8. The DNA G+C content of strain HS6^T was 61.2 mol %. Based on the phylogenetic, physiological and biochemical characteristics, strain HS6^T represents a novel genus and species and the name Motiliproteus sediminis gen. nov., sp. nov., is proposed. The type strain is HS6^T (=ATCC BAA-2613^T=CICC 10858^T).     

Thermovorax subterraneus, gen. nov., sp. nov., a thermophilic hydrogen-producing bacterium isolated from geothermally active underground mine

A thermophilic, rod-shaped, motile, Gram-positive, spore-forming bacterium strain 70B^T was isolated from a geothermally active underground mine in Japan. The temperature and pH range for growth was 50–81°C (optimum 71°C) and 6.2–9.8 (optimum pH 7–7.5), respectively. Growth occurred in the presence 0–2% NaCl (optimum 1% NaCl). Strain 70B^T could utilize glucose, fructose, mannose, mannitol, pyruvate, cellobiose and tryptone as substrates. Thiosulfate was used as electron acceptor. Major whole-cell fatty acids were iso-C_15:0, C_16:0 DMA (dimethyl acetal), C_16:0 and anteiso-C_15:0. The G+C mol% of the DNA was 44.2%. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the closest relatives of strain 70B^T were Thermosediminibacter oceani DSM 16646^T (94% similarity) and Thermosediminibacter litoriperuensis DSM 16647 (93% similarity). The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain 70B^T represents a novel species in a new genus, for which the name Thermovorax subterraneus gen. nov., sp. nov. is proposed. The type strain of Thermovorax subterraneus is 70B^T (=DSM 21563 = JCM 15541).     

Paraherbaspirillum soli gen. nov., sp. nov. isolated from soil

A bacterial strain, designated JS5-2^T, was isolated from soil collected from Jeju Island, Republic of Korea. The cells of the strain were Gram-negative, nonspore forming, catalase- and oxidase-positive, aerobic, nonmotile and rod-shaped. Strain JS5-2^T exhibited 96.2–97.2, 95.1–96.3, and 95.4–95.8% 16S rRNA gene sequence similarities to the genera Herbaspirillum, Oxalicibacterium, and Herminiimonas, respectively. The highest sequence similarities were with Herbaspirillum autotrophicum IAM 14942^T (97.2%) and Herbaspirillum frisingense GSF30^T (97.1%). The major fatty acids of strain JS5-2^T were C_16:0 (35.0%), C_17:0 cyclo (19.9%), C_18:1 ω7c (11.4%), and summed feature 3 (C_16:1 ω7c/C_15:0 iso 2-OH) (15.2%), and the major polar lipids of strain JS5-2^T were diphosphatidylglycerol and an unknown aminophospholipid. The strain contained Q-8 as the predominant ubiquinone. DNA-DNA relatedness values between strain JS5-2^T and H. autotrophicum IAM 14942^T, and H. frisingense GSF30^T were 32 and 35%, respectively. The DNA G+C content of strain JS5-2^T was 59.0 mol%. On the basis of phenotypic, genotypic, and physiological evidence, strain JS5-2^T represents a novel species of a new genus, for which the name Paraherbaspirillum soli gen. nov., sp. nov. is proposed. The type strain JS5-2^T (=KACC 12633^T =NBRC 106496^T) is proposed.     

Thermoanaerobacterium thermostercus sp. nov., a new anaerobic thermophilic hydrogen-producing bacterium from buffalo-dung

A novel thermophilic, anaerobic, rod-shaped bacterium strain, designated Buff, was isolated from buffalo-dung samples collected from a buffalo-farm located in Caserta (Campania, south of Italy). Strain Buff was Gram-positive, motile and no spore-forming. The growth temperature range was 40–65°C with an optimum at 60°C, while pH growth range at 60°C was 5.5–8.0 with an optimum at about pH 6.5. NaCl growth concentration ranged from 0 to 2.0% with an optimum at 0.5% (w/v); no growth was observed with the presence of NaCl 3.0% (w/v). The strain produced ethanol, acetate, lactate, H₂, H₂S and CO₂ by glucose fermentation. The DNA G + C content was 34.4 mol%. As determined by 16S rRNA sequence analysis, this organism belonged to the genus Thermoanaerobacterium. On the basis of the physiological and molecular properties, we propose for strain Buff the new species designation Thermoanaerobacterium thermostercus sp. nov. This novel organism represents the first species of the genus Thermoanaerobacterium isolated from buffalo-dung. The type strain is Buff (=DSM 22141 = ATCC BAA-1776).     

Coprobacillus catenaformis gen. nov., sp. nov., a new genus and species isolated from human feces

Three strains of Eubacterium-like isolates from human feces were characterized by biochemical tests and 16S rDNA analysis. The phenotypic characteristics of the three strains resembled those of the genus Collinsella transferred from the genus Eubacterium recently. However, Eubacterium-like strains were phylogenetically members of the Clostridium subphylum of gram-positive bacteria, and these showed a specific phylogenetic association with Clostridium ramosum and C. spiroforme. C. ramosum and C. spiroforme are gram-positive, anaerobic, spore-forming bacteria that belong to the genus Clostridium, and the G + C contents are 26.0 and 27.4 mol%, respectively. However, the three Eubacterium-like strains had G + C contents of 32.1 to 33.1 mol% and were non-spore-forming rods. Based on phenotypic characteristics, we can differentiate these species, and furthermore, a 16S rDNA sequence divergence of greater than 9% with a new related genus, Coprobacillus, is proposed for the three strains, with one species, Coprobacillus catenaformis. The type strain of C. catenaformis is JCM 10604T.     

Propionicicella superfundia gen. nov., sp. nov., a chlorosolvent-tolerant propionate-forming, facultative anaerobic bacterium isolated from contaminated groundwater

A novel strain, designated as BL-10(T), was characterized using a polyphasic approach after isolation from groundwater contaminated by a mixture of chlorosolvents that included 1,1,2-trichloroethane, 1,2-dichloroethane, and vinyl chloride. Stain BL-10(T) is a facultatively anaerobic bacterium able to ferment glucose to form propionate, acetate, formate, lactate, and succinate. Fermentation occurred in the presence of 1,2-dichloroethane and 1,1,2-trichloroethane at concentrations to at least 9.8 and 5.9 mM, respectively. Cells are Gram-positive, rod-shaped, non-motile, and do not form spores. Oxidase and catalase are not produced and nitrate reduction did not occur in PYG medium. Menaquinone MK-9 is the predominant respiratory quinone and meso-diaminopimelic acid is present in the cell wall peptidoglycan layer. Major cellular fatty acids are C(15:0), iso C(16:0), and anteiso C(15:0). Genomic DNA G + C content is 69.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed strain BL-10(T) to fall within the radiation of genera Propionicimonas and Micropruina. On the basis of the results obtained in this study, it is proposed that strain BL-10(T) should be classified as a novel taxon, for which the name Propionicicella superfundia gen. nov., sp. nov. is proposed. The type strain of Propionicicella superfundia is BL-10(T) (=ATCC BAA-1218(T), =LMG 23096(T)).     

Zymobacter palmae gen. nov., sp. nov., a new ethanol-fermenting peritrichous bacterium isolated from palm sap

Zymobacter palmae gen. nov., sp. nov. was proposed for a new ethanol-fermenting bacterium that was isolated from palm sap in Okinawa Prefecture, Japan. The bacterium is gram-negative, facultatively anaerobic, catalase-positive, oxidase-negative, nonspore-forming and peritrichously flagellated. It requires nicotinic acid for growth. It ferments hexoses, -linked di- and tri-saccarides, and sugar alcohols (fructose, galactose, glucose, mannose, maltose, melibiose, saccharose, raffinose, mannitol and sorbitol). Fifteen percent of maltose in broth medium is effectively fermented, whereas glucose with a concentration higher than 10% delayed growth initiation and decreased growth rates. Maltose is fermented to produce ethanol and CO₂ with a trace amount of acids. Approximately 2 mol of ethanol are produced from 1 mol moiety of hexose of maltose. The organism possesses ubiquinone-9. The G+C content of the DNA is 55.8+-0.4 mol%. Major cellular fatty acids were palmitic and oleic acids and cyclopropanic acid of C_19:0. Characteristic hydroxylated acid was 3-hydroxy dodecanoic acid. The bacterium is distinct from other ethanol-fermenting bacteria belonging to the genera Zymomonas Kluyver and van Niel 1936 and Saccharobacter Yaping et al. 1990 with respect to chemotaxonomic and other phenotypic characters to warrant to compose a new genus and a new species. The type strain is strain T109 (= IAM 14233).Abbreviation IAM IAM Culture Collection, Institute of Applied Microbiology. The University of Tokyo     

Thermobacteroides acetoethylicus gen. nov. and spec. nov., a new chemoorganotrophic,anaerobic, thermophilic bacterium

The taxonomic and metabolic characteristics of a new caldoactive bacterium, Thermobacteroides acetoethylicus, that is prevalent in volcanic features where organic matter is vigorously being decomposed is described. T. acetoethylicus is a nonsporing, obligately anaerobic rod that stains gram-negative and exists singly or in pairs. Electron micrographs revealed peritrichous flagellation and a distinctive outer wall envelope structure without an outer wall membrane layer. The temperature range for growth was >40°C and <80°C; the pH range was between 5.5 and 8.5. The DNA base composition was 31±1 mol% guanosine plus cytosine. Fermentable carbohydrates included glucose, mannose, cellobiose, lactose, maltose, sucrose and starch. Growth on glucose in complex medium was associated with a 30 min doubling time; and ethanol, acetate, H₂/CO₂, butyrate and isobutyrate accounted for a balanced fermentation. Lactic acid was not formed. Growth was inhibited by O₂, 2% NaCl, penicillin, streptomycin, vankomycin and neomycin, but not by chloramphenicol or hydrogen (2 atm). Glucose was metabolized via the Embden-Meyerhoff Pathway. A molar growth yield of 18.3 g cell per mol glucose and an ATP yield of 8 g cell per mol ATP produced was obtained. These results support the absence of detectable cytochromes and suggest that energy conservation is via substrate level phosphorylation alone.Abbreviations DNA deoxyribonucleic acid - ATP adenosine triphosphate - LPBB low phosphate buffered basal - TYEG tryptone yeast extract glucose - O.D. optical density - Y _ATP molar ATP yield - G+C guanosine plus cytosine