Thermoanaerobium brockii gen. nov. and sp. nov., a new chemoorganotrophic,caldoactive, anaerobic bacterium

The isolation of a new anaerobic thermophilic bacterium, Thermoanaerobium brockii, from volcanic features is described. Successful enrichment required a complex medium containing glucose or other fermentable sugars and incubation temperatures of 55–80° C. Strains of T. brockii were gram positive, rods of uneven length that existed singly, in pairs, chains or filaments. Electron micrographs of thin sections of cell revealed a monolayered cell wall and a constrictive or pinching off cell division process. The organism was nonsporeforming, obligately anaerobic and chemoorganotrophic. The optimal temperature for growth was 65–70° C, the maxium was below 85° C and the minimum above 35° C. The doubling time at the optimal temperature for growth was about 1 h. The DNA base composition of three strains of T. brockii varied from 30.0–31.4 mol % guanosine plus cytosine. Fermentable carbohydrates included glucose, sucrose, maltose, lactose, cellobiose and insoluble starch. The fermentation products of cells grown on glucose were ethanol, lactic acid, acetic acid, hydrogen and carbon dioxide. Growth of all strains tested was inhibited by fairly low concentrations of cycloserine, penicillin, streptomycin, tetracycline and chloramphenicol. The possible ecological, evolutionary, and industrial significance, and taxonomic relationships of Thermoanaerobium are discussed.Abbreviations TYEG complex medium containing mineral salts, 0.3% yeast extract, 1.0% tryptone and 0.5% glucose - O.D. optical density - G+C guanosine plus cytosine     

Methanosphaera stadtmaniae gen. nov., sp. nov.: a species that forms methane by reducing methanol with hydrogen

Methanosphaera stadtmaniae is a non-motile, Gram-positive spherical-shaped organism that obtains energy for growth by using hydrogen to reduce methanol to methane. It does not produce methane from hydrogen and carbon dioxide, formate, acetate or methylamines and cannot grow with hydrogen and carbon monoxide, nitrate, fumarate, sulfate or choline. Its pH optimum is 6.5 to 6.9 and its temperature optimum is 36° to 40° C. It is not inhibited by bile salts, inhibitors of the synthesis of folic acid coenzymes, cephalothin or clindamycin but is inhibited by metronidazole, bacitracin, monensin, lasalocid, or bromoethanesulfonate. It requires acetate, carbon dioxide, isoleucine, ammonium, and thiamin for growth and biotin is stimulatory. It does not contain cytochromes and the mol % G+C of its DNA is 25.8. The composition of its cell wall and 16 S rRNA and its immunological fingerprint are consistent with characterization of the organism as a member of a new genus of the family Methanobacteriaceae. The habitat of the type strain is the human large intestine.     

Clostridium grantii sp. nov., a new obligately anaerobic,alginolytic bacterium isolated from mullet gut

A gram-positive, motile, rod-shaped, strictly anaerobic, sporulating bacterium was isolated from an enrichment initiated with mullet gut contents. The organism grew optimally at 30°C and pH6.5, and at a salinity of 1–10³. Out of a variety of polysaccharides tested as growth substrates, only alginate supported growth in either semidefined or complex culture medium. The organism also grew on a variety of mono- and disaccharides. Moles product per 100mol of alginate monomer degraded were: acetate, 186; ethanol, 19; formate, 54; and CO₂, 0.19. Moles product per 100mol of hexose in cellobiose or glucose degraded were: acetate, 135; ethanol,61; formate, 63: and CO₂, 61. Hydrogen was not detectable during the incubations (detection limit, <10^-5atm) and propionate, butyrate, lactate, or succinate were not produced as fermentation end products (<2 mol per 100 mol of monomer). The G+C content of DNA from the bacterium was 30.2±0.3 mol%, and the cell walls contained the peptidoglycan component meso-diaminopimelic acid. A phylogenetic analysis of the 16S rDNA sequence indicated that the organism grouped closely with members of the RNA-DNA homology group 1 of the genus Clostridium. However, it differed from other species of the genus with regard to morphology, growth temperature optimum, substrate range, and fermentation pattern and is therefore designated as a new species of Clostridium; the type strain is A-1 (DSM 8605).     

Fervidobacterium nodosum gen. nov. and spec. nov., a new chemoorganotrophic,caldoactive, anaerobic bacterium

A new species of extremely thermophilic, glycolytic anaerobic bacterium, Fervidobacterium nodosum isolated from a New Zealand hot spring, is described. Fervidobacterium nodosum strains were Gram-negative, motile, non-sporulating obligately anaerobic rods that existed singly, in pairs or in chains. Electron micrographs of thin sections revealed a two-layered cell wall structure. The outer layer of the cell wall produced spheroids, which was a typical feature of this organism. The optimum temperature for growth was 65 to 70° C, the maximum 80° C and the minimum greater than 40° C. Growth occurred between a pH of 6.0 and 8.0 with the optimum being 7.0 to 7.5. The doubling time of Fervidobacterium nodosum at optimal temperature and pH was 105 minutes. The DNA base composition was 33.7% guanine plus cytosine as determined by thermal denaturation. A wide range of carbohydrates including glucose, sucrose, starch and lactose could be utilized by the organism. Lactate, acetate, hydrogen, and carbon dioxide were the major end products of glucose fermentation with lesser amounts of ethanol being formed. Growth was inhibited by tetracycline, penicillin and chloramphenicol indicating that the organism was a eubacterium.     

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     

Psychromonas antarcticus gen. nov., sp. nov., a new aerotolerant anaerobic, halophilic psychrophile isolated from pond sediment of the McMurdo Ice Shelf, Antarctica

A gram-negative, rod- to oval-shaped, aerotolerant anaerobic bacterium was isolated from an anaerobic enrichment inoculated with sediment taken from below the cyanobacterial mat of a high-salinity pond near Bratina Island on the McMurdo Ice Shelf, Antarctica. The organism was positive for terminal oxidase and catalase and was motile by means of a polar flagellum. Optimal growth of anaerobic cultures occurred at 12° C, at pH 6.5, and at an NaCl concentration of 3% (w/v). Of a variety of polysaccharides tested, only starch and glycogen supported growth. No growth was observed on cellulosic substrates and xylan, and the organism was unable to attack esculin. Monosaccharides and disaccharides, including the cyanobacterial cell-wall constituent N-acetyl glucosamine, were fermented. Per 100 mol of hexose, the following products (in mol) were formed: acetate, 60; formate, 130; ethanol, 56; lactate, 73; CO₂, 15; and butyrate, 2. Propionate, ethanol, n-propanol, n-butanol and succinate were not detectable in the culture medium (< 1 mol per 100 mol of monomer). Hydrogen was not detected in the head space (detection limit < 10^–5 atm). Growth yields in aerobic static liquid cultures were slightly higher than those in anaerobic culture, and fermentation favoured acetate at the expense of electron sink products. Growth was inhibited in aerobic shaking cultures, and the organism did not utilize nitrate or sulfate as electron acceptors. The G+C content of the DNA from the bacterium was 42.8 mol%. A phylogenetic analysis indicated that the organism is a member of the γ-subgroup of Proteobacteria, but that it is distinct from other members of this group based on the sequence of its 16S rRNA gene, mol% G+C, morphology, and physiological and biochemical characteristics. It is designated as a new genus and species; the type strain is star-1 (DSM 10704). Received: 17 June 1996 / Accepted: 13 October 1997     

Characterization and phylogeny of a novel methanotroph, Methyloglobulus morosus gen. nov., spec. nov

A novel methanotrophic gammaproteobacterium, strain KoM1, was isolated from the profundal sediment of Lake Constance after initial enrichment in opposing gradients of methane and oxygen. Strain KoM1 grows on methane or methanol as its sole source of carbon and energy. It is a Gram-negative methanotroph, often expressing red pigmentation. Cells are short rods and occur sometimes in pairs or short chains. Strain KoM1 grows preferably at reduced oxygen concentrations (pO₂ = 0.05–0.1 bar). It can fix nitrogen, and grows at neutral pH and at temperatures between 4 and 30 °C. Phylogenetically, the closest relatives are Methylovulum miyakonense and Methylosoma difficile showing 91% 16S rRNA gene sequence identity. The only respiratory quinone is ubiquinone Q8; the main polar lipids are phosphatidyl ethanolamine and phosphatidyl glycerol. The major cellular fatty acids are summed feature 3 (presumably C16:1ω7c) and C16:1ω5c, and the G + C content of the DNA is 47.7 mol%. Strain KoM1 is described as the type strain of a novel species within a new genus, Methyloglobulus morosus gen. nov., sp. nov.     

Anaerobic,alkaliphilic, saccharolytic bacterium <Emphasis Type="Italic">Alkalibacter saccharofermentans</Emphasis> gen. nov., sp. nov. from a soda lake in the Transbaikal region of Russia

Three strains of new obligately anaerobic alkaliphilic bacteria have been isolated as a saccharolytic component from the cellulolytic community of alkaline Lake Nizhnee Beloe (Transbaikal region, Russia), a lake with low salt concentration. DNA analysis of these strains showed an interspecies level of DNA similarity of 96–100%. Strain Z-79820 was selected for further investigations. Cells were Gram-positive, asporogenous, nonmotile short rods with pointed ends. The strain was a true alkaliphile: growth occurred from pH 7.2 to 10.2 with the optimum at pH 9.0. Strain Z-79820 was halotolerant and could grow in medium with up to 10% (w/v) NaCl, with the optimum between 0 and 4% NaCl. The new isolate obligately depended on Na⁺ ions in the form of carbonates or chlorides. Total Na⁺ content needed for optimal growth was 0.46 M Na⁺, with a wide range from 0.023–0.9 M Na⁺ at which growth also occurred. The isolate was a mesophile and grew at temperatures from 6 to 50°C (slow growth at 6 and 15°C) with an optimum at 35°C. The organotrophic organism fermented ribose, xylose, glucose, mannose, fructose, sucrose, mannitol, and peptone. The products of glucose fermentation were acetate, ethanol, formate, H₂, and CO₂. Yeast extract was required for some anabolic needs. The DNA G+C content of the type strain Z-79820 was 42.1 mol%. The new bacterium fell into the 16S rRNA gene cluster XV of the Gram-positive bacteria with low G+C content, where it formed an individual branch. Based on its growth characteristics and genotype traits, we propose the new genus and species named Alkalibacter saccharofermentans with the type strain Z-79820 (=DSM14828), Uniqem-218 (Institute Microbiology, RAS; ).     

Isolation and physiological characterisation of Thiobacillus aquaesulis sp. nov., a novel facultatively autotrophic moderate thermophile

A moderately thermophilic, facultatively chemolithoautotrophic thiobacillus isolated from a thermal sulphur spring is described. It differs from all other species currently known to be in culture. It grows lithoautotrophically on thiosulphate, trithionate or tetrathionate, which are oxidized to sulphate. Batch cultures on thiosulphate do not produce tetrathionate, but do precipitate elemental sulphur during growth. In autotrophic chemostat cultures the organism produces yields on thiosulphate, trithionate and tetrathionate that are among the highest observed for a Thiobacillus. Autotrophic cultures contain ribulose bisphosphate carboxylase. Heterotrophic growth has been observed only on complex media such as yeast extract and nutrient broth. It is capable of autotrophic growth and denitrification under anaerobic conditions with thiosulphate and nitrate. It grows between 30 to 55° C, and pH 7 to 9, with best growth at about 43°C and pH 7.6. It contains ubiquinone Q-8, and its DNA contains 65.7 mol% G+C. The organism is formally described and named as Thiobacillus aquaesulis.Now the Department of Biological Sciences     

Isolation and characterization of a new thermophilic and autotrophic methane producing bacterium:Methanobacterium thermoaggregans spec. nov.

Methanobacterium thermoaggregans is a new thermophilic autotrophic rod-shaped methane producing bacterium. The organism likes to form aggregates during growth and utilizes only H₂ and CO₂ as substrates. Growth optimum is at 65°C with a doubling time of 3.5 h. Optimal growth occurs at pH-values between 7 and 7.5. The addition of yeast extract to the mineral salt medium stimulates growth. The DNA base composition is 42 mol% G+C. The organism was isolated from mud taken from a cattle pasture. Because of its optimal growth temperature and its tendency to form aggregates the nameMethanobacterium thermoaggregans is suggested.Abbreviations G+C Guanine+cytosine     

Isolation and characterization of Dehalospirillum multivorans gen. nov., sp. nov., a tetrachloroethene-utilizing,strictly anaerobic bacterium

A strictly anaerobic bacterium dechlorinating tetrachloroethene (perchloroethylene, PCE) via trichloroethene (TCE) to cis-1,2-dichloroethene (DCE) was isolated from activated sludge with pyruvate plus PCE as energy substrates. The organism, called Dehalospirillum multivorans, is a gram-negative spirillum that does not form spores. The G+C content of the DNA was 41.5 mol%. According to 16S rRNA gene sequence analysis, D. multivorans represents a new genus and a new species belonging to the epsilon subdivision of Proteobacteria. Quinones, cytochromes b and c, and corrinoids were extracted from the cells. D. multivorans grew in defined medium with PCE and H₂ as sole energy sources and acetate as carbon source; the growth yield under these conditions was 1.4g of cell protein per mol chloride released. Alternatively to PCE, fumarate and nitrate could serve as electron acceptors; sulfate could not replace fumarate, nitrate, or PCE in this respect. In addition to H₂, the organism utilized a variety of electron donors for dechlorination (pyruvate, lactate, ethanol, formate, glycerol). Upon growth on pyruvate plus PCE, the main fermentation products formed were acetatc, lactate, DCE, and H₂. At optimal pH (7.3–7.6) and temperature (30°C), and in the presence of pyruvate (20mM) and PCE (160M), a dechlorination rate of about 50 nmol min^-1 (mg cell protein)^-1 and a doubling time of about 2.5h were obtained with growing cultures. The ability to reduce PCE to DCE appears to be constitutive under the experimental conditions applied since cultures growing in the absence of PCE for several generations immediately started dechlorination when transferred to a medium containing PCE. The organism may be useful for bioremediation of environments polluted with tetrachloroethene.Abbreviations PCE Perchloroethylene, tetrachloroethene - TCE Trichloroethene - DCE cis-1,2-Dichloroethene - CHC Chlorinated hydrocarbon     

Isolation and characterization of a novel mesophilic,fresh-water methanogen from river sediment Methanoculleus oldenburgensis sp. nov.

A new mesophilic, irregular coccoid methanogen isolated from a river sediment is described. Hydrogen plus carbon dioxide or formate served as substrates for methanogenesis in a mineral salt medium. For growth acetate is strictly required. Elevated levels of sodium chloride were not required and were inhibitory at concentrations above 1.5% (w/v). The optimal growth temperature was at 45°C. The DNA base ratio was 48.6±1 mol% G+C. The polar lipid pattern and the polyamine content were similar to that found in several Methanoculleus species. The new isolate CB-1 was assigned as Methanoculleus oldenburgensis (DSM 6216).     

Isolation and physiological characterisation of Thiobacillus thyasiris sp. nov., a novel marine facultative autotroph and the putative symbiont of Thyasira flexuosa

A novel facultatively chemolithoautotropic Thiobacillus, isolated from the gill tissue of the marine bivalve Thyasira flexuosa, is described. It is believed to be the symbiont from this animal, providing the animal with carbon fixed by the Calvin cycle. The organism grows lithoautotrophically on thiosulphate, tetrathionate and elemental sulphur, which are oxidised to sulphate. It oxidizes sulphide, thiosulphate, trithionate, tetrathionate and hexathionate, but not thiocyanate. Kinetic constants for these substrates are presented. In autotrophic batch culture it produces yields that are among the lowest reported for thiosulphate or tetrathionate as energy substrates (1.25 and 2.5 g cell-carbon per mol substrate, respectively). Autotrophic cultures contain ribulose bisphosphate carboxylase and excreted 20% of their fixed carbon into the medium during growth. Mixotrophic growth on acetate and thiosulphate resulted in partial repression of the carboxylase. The organism is slightly halophilic and markedly halotolerant, showing optimum growth at about pH 7.5 and maximum growth rate at 37° C. It contains ubiquinone Q-10 and its DNA contains 52 mol % G+C. These characteristics distinguish it from any other Thiobacillus or Thiomicrospira species previously described. The organism is formally described and named as Thiobacillus thyasiris.     

Isolation and characterization of Methanocorpusculum parvum,gen. nov., spec. nov., a new tungsten requiring,coccoid methanogen

A new mesophilic, monotrichously flagellated methane-producing coccus of 1m in diameter was isolated from an anaerobic sour whey digester, originally inoculated with sewage sludge. Growth and methane production were observed with H₂/CO₂, formate and — less effectively — with 2-propanol/CO₂. The isolate grew at temperatures between 15° C and 45° C with the optimum at around 37° C. Acetate, yeast extract and tungstate were required in the medium. Clarified rumen fluid stimulated growth.The DNA of the new methanogen has a G+C content of 48.5 mol%. Comparative 16 S rRNA oligonucleotide cataloguing allows to define the new isolate as a member of a new genus of the order Methanomicrobiales. Further evidence for this is provided by the antigenic crossreactivity with anti-S probes and by metabolic features.Because of its small size the new methanogen is named Methanocorpusculum parvum.This work was supported by a grant of the Deutsche Forschungsgemeinschaft DFG to J. W. and E. S. Immunologic studies were supported in part by grants No. DE-FGO2-84 R 13197 from the U.S. Department of Energy, and No. 261.81/82 from the North Atlantic Treaty Organization (NATO)     

Heliorestis daurensis, gen. nov. sp. nov., an alkaliphilic rod-to-coiled-shaped phototrophic heliobacterium from a Siberian soda lake

A novel alkaliphilic heliobacterium was isolated from microbial mats of a low-salt alkaline Siberian soda lake. Cells of the new organism were tightly coiled when grown in coculture with a rod-shaped bacterium, but grew as short filaments when finally obtained in pure culture. The new phototroph, designated strain BT-H1, produced bacteriochlorophyll g and a neurosporene-like pigment, and lacked internal photosynthetic membranes. Similar to other heliobacteria, strain BT-H1 grew photoheterotrophically on a limited range of organic compounds including acetate and pyruvate. Sulfide was oxidized to elemental sulfur and polysulfides under photoheterotrophic conditions; however, photoautotrophic growth was not observed. Cultures of strain BT-H1 were alkaliphilic, growing optimally at pH 9, and unlike other heliobacteria, they grew optimally at a temperature of 25 °C rather than at 40 °C or above. Analysis of the 16S rRNA gene sequence of the new organism showed that it groups within the heliobacterial clade. However, its branching order was phylogenetically basal to all previously investigated species of heliobacteria. The G+C content of the DNA of strain BT-H1 (44.9 mol%) was also quite distinct from that of other heliobacteria. This unique assemblage of properties implicates strain BT-H1 as a new genus and species of the heliobacteria, Heliorestis daurensis, named for its unusual morphology (“restis” is Latin for “rope”) and for the Daur Steppe in Russia in which these soda lakes are located. Received: 15 March 1999 / Accepted: 25 June 1999     

Isolation and characterization ofMethanobrevibacter oralis sp. nov.

A new coccobacillary, nonmotile, Gram-positive, methane-producing organism was isolated from human subgingival plaque. Both hydrogen and carbon dioxide were required for growth. No methane was produced from acetate, formate, or methanol. The optimum pH was 6.9–7.4, and the optimum temperature was 36–38°C. Fecal extract was required for growth, and a volatile fatty acid mixture was highly stimulatory. The DNA G+C content was 28 mol%. On the basis of these characteristics, DNA-DNA hybridization studies, and electrophoretic analysis of cellular proteins, the isolate was considered a new species and namedMethanobrevibacter oralis.     

Ectothiorhodospira halochloris sp. nov., a new extremely halophilic phototrophic bacterium containing bacteriochlorophyll b

A new bacteriochlorophyll b containing phototrophic bacterium was isolated from extremely saline and alkaline soda lakes in Egypt. Enrichment and isolation were performed using a synthetic medium with high contents of sodium carbonate, sodium sulfate and sodium chloride. Photoautotrophic growth occurred with hydrogen sulfide as photosynthetic electron donor. During oxidation of sulfide to sulfate extracellular elemental sulfur globules appeared in the medium. Cells were also capable to grow under photoheterotrophic conditions with acetate, propionate, pyruvate, succinate, fumarate or malate as carbon sources and electron donors. Under these conditions sulfate was assimilated. Optimal growth under the applied experimental conditions occurred at a total salinity of 14–27%, a pH-range between 8.1 and 9.1 and a temperature between 47°C and 50°C. The cells were 0.5–0.6 m wide and, depending on cultural conditions, 2.5–8.0 m long; they were spiral shaped, multiplied by binary fission and were motile by means of bipolar flagella. Intercytoplasmic photosynthetic membranes were present as stacks. Bacteriochlorophyll b was the main photosynthetic pigment; small amounts of carotenoids were mainly present as glucosides of rhodopin and its methoxy derivative. The new organism is described as Ectothiorhodospira halochloris.Dedicated to Professor C. B. van Niel on the occasion of his 80th birthday     

Stetteria hydrogenophila, gen. nov. and sp. nov., a novel mixotrophic sulfur-dependent crenarchaeote isolated from Milos, Greece

A new hyperthermophilic, strictly anaerobic crenarchaeote, Stetteria hydrogenophila DSM11227 representing a new genus within the family of Desulfurococcaceae, was isolated from the sediment of a marine hydrothermal system at Paleohori Bay in Milos, Greece. Cells are gram-negative irregular and disc-shaped cocci, 0.5–1.5 μm in diameter, which are flagellate and can form cytoplasmatic protrusions up to 2 μm in length. The strain grew optimally at 95°C at pH 6.0 and at a NaCl concentration of 3%. The organism grew mixotrophically on peptide substrates. It required elemental sulfur as an external electron acceptor, and in addition, its growth was completely dependent on the presence of molecular hydrogen. Sulfur could be replaced by thiosulfate. H₂S, CO₂, acetate, and ethanol were identified as products of metabolism. The G + C content of DNA was 65 mol%. Analysis of its phylogenetic position by sequence analysis of 16S rRNA placed this organism in the family of Desulfurococcaceae. The dependence of this organism on both hydrogen and sulfur during growth on peptide substrates distinguishes Stetteria from all previously described species of Crenarchaeota. Received: September 4, 1996 / Accepted: November 12, 1996     

Tepidimonas taiwanensis sp. nov., a novel alkaline-protease-producing bacterium isolated from a hot spring

The bacterial strain designated I1-1^T was isolated from a hot spring located in the Pingtung area, southern Taiwan. Cells of this organism were Gram reaction negative rods, motile by a single polar flagellum. Optimum conditions for growth were 55°C and pH 7. Strain I1-1^T grew well in lower nutrient media such as 5–10% Luria–Bertani broth, and its extracellular products expressed alkaline protease activity. The 16S rRNA gene sequence analysis indicates that strain I1-1^T is a member of -Proteobacteria. On the basis of a phylogenetic analysis of 16S rDNA sequences, DNA–DNA similarity data, whole-cell protein analysis, physiological and biochemical characteristics, as well as fatty acid compositions, the organism belonged to the genus Tepidimonas and represented a novel species within this genus. The predominant cellular fatty acids of strain I1-1^T were 16:0 (about 41%), 18:1 7c (about 13%), and summed feature 3 [16:1 7c or 15:0 iso 2OH or both (about 26%)]. Its DNA base ratio was 68.1 mol%. We propose to classify strain I1-1^T (=BCRC 17406^T=LMG 22826^T) as Tepidimonas taiwanensis sp. nov.     

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