Methanosarcina baltica,sp. nov., a novel methanogen isolated from the Gotland Deep of the Baltic Sea

A novel methanogen, Methanosarcina baltica GS1-AT, DSM 14042, JCM 11281, was isolated from sediment at a depth of 241 m in the Gotland Deep of the Baltic Sea. Cells were irregular, monopolar monotrichous flagellated cocci 1.5-3 microm in diameter often occurring in pairs or tetrads. The catabolic substrates used included methanol, methylated amines, and acetate, but not formate or H2/CO2. Growth was observed in a temperature range between 4 degrees and 27 degrees C with an optimum at 25 degrees C. The doubling time with methanol as substrate was 84 h at 25 degrees C, 120 h at 9 degrees C, and 167 h at 4 degrees C. The doubling time with acetate as substrate was 252 h at 25 degrees C and 425 h at 20 degrees C. After the transfer of methanol-grown cultures, long lag phases were observed that lasted 15-20 days at 25 degrees C and 25 days at 4 degrees -9 degrees C. The NaCl optimum for growth was 2%-4%, and the fastest growth occurred within a pH range of 6.5-7.5. Analysis of the 16S rDNA sequence revealed that the strain was phylogenetically related to Methanosarcina. The sequence similarity to described species of <95.7% and its physiological properties distinguished strain GS1-A(T) from all described species of the genus Methanosarcina.     

Chimaereicella alkaliphila gen. nov., sp. nov., a Gram-negative alkaliphilic bacterium isolated from a nonsaline alkaline groundwater

A Gram-negative bacterium designated AC-74(T) was isolated from a highly alkaline groundwater environment (pH 11.4). This organism formed rod-shaped cells, is strictly aerobic, catalase and oxidase positive, tolerates up to 3.0% NaCl, has an optimum growth temperature of 30 degrees C, but no growth occurs at 10 or 40 degrees C, and an optimum pH value of 8.0, but no growth occurs at pH 7.0 or 11.3. The predominant fatty acids are iso-15:0, iso-17:1 omega9c and 16:1 omega7c and or iso-15:2OH. The G+C content of DNA was 43.5mol%. The phylogenetic analyses of the sequences of the 16s RNA genes indicated that strain AC-74(T) belongs to the family "Flexibacteriaceae" and is phylogenetically equidistant ( approximately 94.5%) from the majority of the species of the genus Algoriphagus and from the genus Hongiella. Based on the phylogenetic analyses and distinct phenotypic characteristics, we are of the opinion that strain AC-74(T), represents a new species of the novel genus for which we propose the name Chimaereicella alkaliphila gen. nov., sp. nov.     

A psychrotolerant Caulobacter sp. from Russian polar tundra soil

Strain Z-0024, a psychrotolerant aerobic heterotrophic representative of the prosthecate bacteria of the genus Caulobacter, was isolated from a methanotrophic enrichment obtained from Russian polar tundra soil. The cells of the new isolate are vibrios (0.5-0.6 x 1.3-1.8 microm) with a polar stalk. The organism grows in a temperature range from 5 to 36 degrees C, with an optimum at 20 degrees C. The pH range for growth is from 4.5 to 7.0 with an optimum at pH 6.0. Strain Z-0024 utilizes a wide range of organic compounds: sugars, amino acids, volatile fatty acids, and primary alcohols. It tolerates a NaCl concentration in the medium of up to 15 g/l. The G + C content of DNA is 66.6 mol %. The 16S rRNA gene sequence analysis revealed that strain Z-0024 belongs to the cluster of Caulobacter species, showing a 98.8-99.2% sequence similarity to them. DNA-DNA hybridization revealed a low level of homology (24%) between strain Z-0024 and C. vibrioides ATCC 15252. The new isolate is described as Caulobacter sp. Z-0024.     

Taxonomic characterization of <Emphasis Type="Italic">Haloferax</Emphasis> sp. ("<Emphasis Type="Italic">H. alicantei</Emphasis>") strain Aa 2.2: description of <Emphasis Type="Italic">Haloferax lucentensis</Emphasis> sp. nov.

An extremely halophilic archaeon, previously named as Haloferax sp. strain Aa 2.2 or "Haloferax alicantei" that has been extensively used for genetic studies with halobacteria, was taxonomically characterized by using phenotypic tests (including morphological, physiological, biochemical and nutritional features), DNA-DNA hybridization and 16S rRNA sequence phylogenetic analysis. This organism was isolated in 1986 by Torreblanca et al. from a pond of a Spanish saltern located in Alicante. The cells were pleomorphic, Gram negative and grew optimally at 25% NaCl. The polar lipid composition was similar to that of species of the genus Haloferax. The DNA G+C content of this strain was 64.5 mol%. Phylogenetic analysis based on 16S rRNA sequence comparison confirmed that this archaeon is a member of the genus Haloferax and was most closely related to Haloferax volcanii. DNA-DNA hybridization between strain Aa 2.2 and the type strain of all named species of the genus Haloferax revealed low levels of relatedness (25-2%), supporting the placement of this organism in a new species. On the basis of the phenotypic characteristics, molecular data and phylogenetic analysis we propose to name strain Aa 2.2 as a new species, Haloferax lucentensis sp. nov. The type strain is Aa 2.2 (=JCM 9276=NCIMB 13854=CIP 107410=DSM 14919=CECT 5871=CCM 7023).     

Halonatronum saccharophilum gen. nov. sp. nov--a new haloalkalophilic bacteria from the order Haloanaerobiales from Lake Magadi

A new alkaliphilic and moderately halophilic chemoorganotrophic anaerobic bacterium (strain Z-7986), which is spore-forming, rod-shaped, and has a gram-negative cell wall pattern, was isolated from the coastal lagoon mud of the highly mineralized Lake Magadi (Kenya). The organism is an obligatorily carbonate- and sodium chloride-dependent. It is a motile peritrichously flagellated rod that has developed within 3-17% NaCl concentration (with an optimum at 7-12% NaCl) and within a pH range of 7.7-10.3 (with an optimum at pH values of 8-8.5). It is a moderate thermophile with a broad temperature optimum from 36-55 degrees C and a growth maximum at 60 degrees C. The bacterium catabolizes glucose, fructose, sucrose, maltose, starch, glycogen, N-acetyl-D-glucosamine, and, to a slight degree, peptone and yeast extract. Its anabolism requires yeast extract or casamino acids. Glucose fermentation yields formate, acetate, ethanol, H2, and CO2. The bacterium is sulfidetolerant and capable of the nonspecific reduction of S0 to H2S. The G + C content of the DNA is 34.4 mol %. The analysis of the 16S rRNA sequence revealed that strain Z-7986 belongs to the order Haloanaerobiales and represents a new genus in the family Halobacteroidaceae. We suggest calling the organism Halonatronum saccharophilum gen. nov. sp. nov. The type strain of this species is Z-7986T (= DSM13868, = Uniqem 211).     

<Emphasis Type="Italic">Streptomyces gulbargensis</Emphasis> sp. nov., isolated from soil in Karnataka,India

During the course of screening for industrially important microorganisms, an alkali-tolerant and thermotolerant actinomycete, strain DAS 131T, was isolated from a soil sample collected from the Gulbarga region, Karnataka province, India. The strain was characterized by a polyphasic approach that showed that it belonged to the genus Streptomyces. Growth was observed over a wide pH range (pH 6-12) and at 45 degrees C. The 16S rRNA gene sequence of strain DAS 131T was deposited in the GenBank database under the accession number DQ317411. 16S rRNA gene sequence analysis revealed that strain DAS 131T was most closely related to Streptomyces venezuelae ISP 5230T (AY999739) with a sequence similarity of 99.5% (8 nucleotide differences out of 1,477). Despite this very high sequence similarity, strain DAS 131T was phenetically distinct from S. venezuelae. The DNA relatedness between these strains was 54%, indicating that strain DAS 131T is a distinct genomic species. On the basis of phenetic and genetic analyses, strain DAS 131T is classified as a new species in the genus Streptomyces, for which we propose the name Streptomyces gulbargensis sp. nov.     

Isolation and characterization of new strains of methanogens from cold terrestrial habitats

Five strains of methanogenic archaea (MT, MS, MM, MSP, ZB) were isolated from permanently and periodically cold terrestrial habitats. Physiological and morphological studies, as well as phylogenetic analyses of the new isolates were performed. Based on sequences of the 16S rRNA and methyl-coenzyme M reductase a-subunit (mcrA) genes all new isolates are closely related to known mesophilic and psychrotolerant methanogens. Both, phylogenetic analyses and phenotypic properties allow to classify strains MT, MS, and MM as members of the genus Methanosarcina. Strain MT is a new ecotype of Methanosarcina mazei, whereas strains MM and MS are very similar to each other and can be assigned to the recently described psychrotolerant species Methanosarcina lacustris. The hydrogenotrophic strain MSP is a new ecotype of the genus Methanocorpusculum. The obligately methylotrophic strain ZB is closely related to Methanomethylovorans hollandica and can be classified as new ecotype of this species. All new isolates, including the strains from permanently cold environments, are not true psychrophiles according to their growth temperature characteristics. In spite of the ability of all isolates to grow at temperatures as low as 1-5 degrees C, all of them have their growth optima in the range of moderate temperatures (25-35 degrees C). Thus, they can be regarded as psychrotolerant organisms. Psychrotolerant methanogens are thought to play an important role in methane production in both, habitats under seasonal temperature variations or from permanently cold areas.     

Isolation and characterization of a new type of aerobic,oxalic acid utilizing bacteria,and proposal of Oxalicibacterium flavum gen. nov., sp. nov

A mesophilic, aerobic oxalic acid utilizing yellow-pigmented bacterium has been isolated from litter of oxalate producing plants in the region of Izmir (Turkey). It is motile by means of 1-3 polar flagella. Optimal growth occurred between 25-30 degrees C at pH 6.9. The G+C content of DNA is 62-64 mol % (Tm). Based on its morphological and biochemical features the organism belongs to the genus Pseudomonas, but differs from all the previously described species. The taxonomic relationships among strains described as or previously tentatively assigned to the genus Pseudomonas were investigated using numerical classification, DNA base composition and DNA-DNA hybridization. 16S rDNA sequences were determined for the strain TA17. On the basis of 16S rDNA sequence comparisons, physiological and biochemical characteristics, it is proposed to classify TA17T in a new genus and species for which the name Oxalicibacterium flavum gen. nov., sp. nov. is proposed. The type strain is TA17T (= NEU98T, = LMG 21571T).     

Bacillus nematocida sp. nov., a novel bacterial strain with nematotoxic activity isolated from soil in Yunnan, China

An endospore-forming bacterium, designated strain B-16T, was isolated from a forest soil sample in Yunnan, China. The isolate presented remarkable nematotoxic activity against nematode Panagrellus redivivus. The organism was strictly aerobic, motile, spore forming and rod shaped, catalase- and oxidase-positive. The predominant isoprenoid quinone was menaquinone 7 (MK-7). The major cellular fatty acid profiles were anteiso-C15:0 (48.67%), iso-C15:0 (13.45%), C16:0 (9.06%) and anteiso-Cl7:0 (8.29%). The DNA G+C content was 46%. Phylogenetic analyses based on 16S rDNA sequence revealed that isolate belongs to the genus Bacillus. Strain B-16T exhibited high 16S rDNA similarity with its closest neighbors Bacillus vallismortis (99.79%), B. subtilis (99.43%), B. atrophaeus (99.43%), B. amyloliquefaciens (99.36%), B. licheniformis (98.0%) and less than 97.0% with all the other relative type strains in the genus Bacillus. The phenotypic and genotypic characteristics and DNA-DNA relatedness data indicate that strain B-16T should be distinguished from all the relative species of genus Bacillus. Therefore, on the basis of the polyphasic taxonomic data presented, a new species of the genus Bacillus, B. nematocida, with the type strain B-16T ( = CGMCC 1128T) is proposed. The GenBank accession number for the sequence reported in this paper is AY820954.     

Marinospirillum alkaliphilum sp. nov., a new alkaliphilic helical bacterium from Haoji soda lake in Inner Mongolia Autonomous Region of China

A new helical, alkaliphilic, gram-negative, chemoorganotrophic bacterium designated strain Z4T was isolated from Haoji soda lake in Inner Mongolia Autonomous Region, China. The isolate grows at salinities between 0.2% and 5.0% (w/v) NaCl and pH range 7.0-11.0, with an optimum at 2.0% (w/v) NaCl and pH 9.5. Its growth temperature ranges from 8 degrees to 49 degrees C with an optimum at 37 degrees C. The G+C content of the DNA is 46.8 mol%. The major isoprenoid quinone is ubiquinone 8 (Q-8). Phylogenetic analyses based on 16S rDNA sequence comparison indicates that strain Z4T is a member of the genus Marinospirillum. Phenotypic features and DNA-DNA homology of less than 20% with the described species of Marinospirillum support the view that strain Z4T represents a new species of the genus Marinospirillum. Strain Z4T (= AS 1.2746) is proposed as the type strain of a new species, named Marinospirillum alkaliphilum sp. nov.     

Acetobacterium tundrae sp. nov., a new psychrophilic acetogenic bacterium from tundra soil

A new psychrophilic, anaerobic, acetogenic bacterium from the tundra wetland soil of Polar Ural is described. The organism fermented H2/CO2, formate, methanol, and several sugars to acetate as the sole end-product. The temperature range for growth was 1-30 degrees C with an optimum at 20 degrees C. The bacterium showed no growth at 32 degrees C. Cells were gram-positive, oval-shaped, flagellated rods 0.7-1.l x 1.1-4.0 microm in size when grown at 1-20 degrees C. At 25-30 degrees C, the cell size increased up to 2-3 x 10-15 microm due to a defect in cell division. The DNA G+C content of the organism was 39.2 mol%. Based upon 16S rDNA analysis and DNA-DNA reassociation studies, the organism was classified in the genus Acetobacterium as a new species, for which the name Acetobacterium tundrae sp. nov. is proposed. The type strain is Z-4493 (=DSM 9173T).     

Caldimonas taiwanensis sp. nov., a amylase producing bacterium isolated from a hot spring

During screening for amylase-producing bacteria, a strain designated OnlT was isolated from a hot spring located in Pingtung area, which is near the very southern part of Taiwan. Cells of this organism were Gram-negative rods motile by means of a single polar flagellum. Optimum conditions for growth were 55 degrees C and pH 7. Strain On1(T) grew well in minimal medium containing starch as the sole carbon source, and its extracellular products expressed amylase activity. The 16S rRNA gene sequence analysis indicates that strain On1(T) is a member of beta-Proteobacteria. On the basis of a phylogenetic analysis of 16S rDNA sequences, DNA-DNA similarity data, physiological and biochemical characteristics, as well as fatty acid compositions, the organism belonged to the genus Caldimonas and represented a novel species within this genus. The predominant cellular fatty acids of strain On1(T) were 16:0 (about 30%), 18:1 omega 7c (about 20%) and summed feature 3 (16:1 omega 7c or 15:0 iso 2OH or both [about 31%]). Its DNA base ratio was 65.9 mol% G + C. We propose to classify strain On1(T) (= BCRC 17405T = LMG 22827T) as Caldimonas taiwanensis sp. nov.     

Methanol utilization by a novel thermophilic homoacetogenic bacterium,Moorella mulderi sp. nov., isolated from a bioreactor

A thermophilic, anaerobic, spore-forming bacterium (strain TMS) was isolated from a thermophilic bioreactor operated at 65 degrees C with methanol as the energy source. Cells were gram-positive straight rods, 0.4-0.6 microm x 2-8 microm, growing as single cells or in pairs. The temperature range for growth was 40-70 degrees C with an optimum at 65 degrees C. Growth was observed from pH 5.5 to 8.5, and the optimum pH was around 7. The salinity range for growth was 0-45 g NaCl l(-1 )with an optimum at 10 g l(-1). The isolate was able to grow on methanol, H(2)-CO(2 )(80/20%, v/v), formate, lactate, pyruvate, glucose, fructose, cellobiose and pectin. The bacterium reduced thiosulfate to sulfide. The G+C content of the DNA was 53 mol%. Comparison of 16S rRNA genes revealed that strain TMS is related to Moorella glycerini (96%, sequence similarity), Moorella thermoacetica (92%) and Moorella thermoautotrophica (92%). On the basis of physiological and phylogenetic differences, strain TMS is proposed as a new species within the genus Moorella, Moorella mulderi sp. nov. (=DSM 14980, =ATCC BAA-608).     

Pseudoxanthomonas kaohsiungensis, sp. nov., a novel bacterium isolated from oil-polluted site produces extracellular surface activity

During screening for biosurfactant-producing bacteria, a strain designated J36T was isolated from oil-polluted site near Kaohsiung city located in southern Taiwan. Cells of this organism were gram-negative rods motile by means of a single polar flagellum. Strain J36T grew well in complex media under optimum conditions of 35 degrees C and pH 7. The extracellular products of the strain expressed emulsification activity. During cultivation on olive oil as the sole carbon and energy source, the culture supernatant of strain J36T reduced surface tension of the medium from 68 to 32.6 dyne/cm. The 16S rRNA gene sequence analysis indicates that strain J36T is a member of Xanthomonas group within the gamma-Proteobacteria. The organism belongs to the genus Pseudoxanthomonas and represents a novel species within this genus according to 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 predominant cellular fatty acids of strain J36T were 15:0 iso (about 26%), 17:1 iso omega9c (about 25%), and 15:0 anteiso (about 10%). Its DNA base ratio was 60.1 mol% G+C. We propose to classify strain J36T (= BCRC 17375T = LMG 22530T) as Pseudoxanthomonas kaohsiungensis sp. nov.     

Clostridium asparagiforme sp. nov., isolated from a human faecal sample

An obligatory anaerobic, Gram-positive, rod-shaped organism was isolated from faeces of a healthy human donor. It was characterized using biochemical, phenotypic and molecular taxonomic methods. The organism produced acetate, lactate, and ethanol as the major products of glucose fermentation. The G + C content was 53 mol%. Based on comparative 16S rRNA gene sequencing, the unidentified bacterium is a member of the Clostridium subphylum of the Gram-positive bacteria, and most closely related to species of the Clostridium coccoides cluster (rRNA cluster XIVa) [M.D. Collins et al., The phylogeny of the genus Clostridium: proposal of five new genera and eleven new species combinations, Int. J. Syst. Bacteriol. 44 (1994) 812-826]. Clostridium bolteae and Clostridium clostridioforme were identified as the most closely related described species. A 16S rRNA sequence divergence value of > 3% suggested that the isolate represents a new species. This was also supported by the gyrase-encoding gyrB gene sequences. Based on these findings, we propose the novel bacterium from human faeces to be classified as a new species, Clostridium asparagiforme. The type strain of C. asparagiforme is N6 (DSM 15981 and CCUG 48471).     

Ruminococcus luti sp. nov., isolated from a human faecal sample

A strain of an unidentified strictly anoxic, gram-postive, non-motile Ruminococcus-like bacterium was isolated from a human faecal sample. The organism used carbohydrates as fermentable substrates, produced acetate, succinate, and hydrogen as the major products of glucose metabolism, and possessed a G + C content of 43.3 mol%. The morphological and biochemical characteristics of the organism were consistent with its assignment to the genus Ruminococcus but it did not correspond to any recognized species of this genus. Comparative 16S rRNA gene sequencing showed the unidentified bacterium represents a previously unrecognised sub-line within the Clostridium coccoides rRNA group of organisms. The nearest relative of the unknown bacterium corresponded to Ruminococcus obeum but a 16S rRNA sequence divergence value of >3% demonstrated it represents a different species. Based on the presented findings a new species, Ruminococcus luti, is described. The type strain of Ruminococcus luti is BInIX(T) (DSM 14534T, CCUG 45635T).     

Erythrobacter vulgaris sp. nov., a novel organism isolated from the marine invertebrates

Four yellow-pigmented, gram-negative, chemoorganotrophic aerobic bacteria were isolated from starfish Stellaster equestris (strains 022-2-10T, 022-2-9, and 022-2-12) and soft coral (unidentified species) (strain 022-4-7) collected in the South China Sea. 16S rRNA gene sequence-based analyses of the new organisms revealed that Erythrobacter spp. were the closest relatives and shared the highest similarity of 98.7% to E. citreus, 98.5% to E. flavus, 97.9% to E. litoralis and 97.6% to E. longus. The novel organisms were tolerant to 3-6% NaCl, grew between 10 degrees C and 40 degrees C, and were not able to degrade gelatin, casein, and agar, while degraded Tween 80. Two strains (022-2-9 and 022-2-12) could weakly degrade starch. All strains produced a large pool of carotenoids and did not have Bacteriochlorophyll a. Phosphatidylethanolamine (30-36%), phosphatidylglycerol (39-46%), and phosphatidylcholine (21-27%) were the predominant phospholipids. Sphingoglycolipid was not detected. The major fatty acids were 16:0 (6-11%), 16:1omega7 (12-15%), and 18:1omega7 (46-49%). The two-hydroxy fatty acids, 13:0-2OH, 14:0-2OH, 15:0-2OH, 16:0-2OH were also present. The G + C content of the DNAs ranged from 61 to 62 mol%. The level of DNA similarity among four strains was conspecific and ranged from 94% to 98%. Even though new strains and other species of the genus had rather high level of 16S rRNA gene sequence similarities, DNA-DNA hybridization experiments showed only 33-39% of binding with the DNA of the type strains. On the basis of these results and the significant differences demonstrated in the phenotypic and chemotaxonomic characteristics, it is suggested that the new organisms be classified as a novel species; the name Erythrobacter vulgaris sp. nov. is proposed. The type strain is 022-2-10T (= KMM 3465T = CIP 107841T).     

Helicobacter nemestrinae sp. nov., a spiral bacterium found in the stomach of a pigtailed macaque (Macaca nemestrina)

A new microaerophilic, spirally curved, rod-shaped bacterium was isolated from the gastric mucosa of a pigtailed macaque (Macaca nemestrina). The gram-negative cells of this bacterium are oxidase, catalase, and urease positive and strongly resemble Helicobacter pylori (Campylobacter pylori) cells. Like H. pylori, this organism does not metabolize glucose, does not reduce nitrate or produce indole, does not produce H2S from triple sugar iron agar, does not hydrolyze hippurate or esculin, and does not grow in the presence of 1% glycine, 1.5% salt, or 1% bile. Also like H. pylori, it is resistant to nalidixic acid and susceptible to cephalothin. However, unlike H. pylori, the colorless colonies are flat and have irregular edges. This organism has a unique cellular fatty acid composition, forming a new gas-liquid chromatography group, group K, and a distinctive DNA content (24 mol% guanine plus cytosine). It exhibits less than 10% DNA-DNA homology (as determined by the nylon filter blot method at 65 degrees C) with other members of the genus Helicobacter. Although the levels of DNA relatedness between previously described Helicobacter species and the new organism are low (less than 10%) and the difference in guanine-plus-cytosine content is large (24 versus 36 to 41 mol%), the genus Helicobacter is the only genus in which it is logical to include the organism at this time. We propose that our single strain represents a new species, Helicobacter nemestrinae, and we designate strain T81213-NTB (= ATCC 49396) as the type strain.     

Transfer of Methanolobus siciliae to the genus Methanosarcina, naming it Methanosarcina siciliae, and emendation of the genus Methanosarcina

A sequence analysis of the 16S rRNA of Methanolobus siciliae T4/M(T) (T = type strain) showed that this strain is closely related to members of the genus Methanosarcina, especially Methanosarcina acetivorans C2A(T). Methanolobus siciliae T4/M(T) and HI350 were morphologically more similar to members of the genus Methanosarcina than to members of the genus Methanolobus in that they both formed massive cell aggregates with pseudosarcinae. Thus, we propose that Methanolobus siciliae should be transferred to the genus Methanosarcina as Methanosarcina siciliae.     

Desulfovibrio aerotolerans sp. nov., an oxygen tolerant sulphate-reducing bacterium isolated from activated sludge

A new mesophilic sulphate-reducing bacterium, designated strain DvO5(T) (T=type strain), was isolated from the outermost sulphate reduction-positive most-probable-number tube (10(-6) dilution) of an activated sludge sample, which had been oxygenated at 100% air saturation for 120 h. The motile, Gram-negative, curved 1 by 2-5 microm and non-spore-forming cells of strain DvO5(T) existed singly or in chains. Strain DvO5(T) grew optimally at 29 degrees C, pH 6.9 and 0.05% (w/v) NaCl in a medium containing lactate, sulphate and yeast extract. Sulphite, thiosulphate and elemental sulphur also served as electron acceptors whereas nitrate, nitrite or ferric iron were not reduced. Lactate, pyruvate, H(2) (with acetate as carbon source), ethanol and glycerol efficiently supported growth as electron donors. Pyruvate and malate were fermented. Strain DvO5(T) reduced oxygen by oxidising endogenous polyglucose at rates ranging from 0.4 to 6.0 nmol O(2)/mg protein min depending on the oxygen concentration, the highest rates being observed at atmospheric oxygen saturation. The G+C content of the DNA was 57.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain DvO5(T) was a member of the genus Desulfovibrio with D. magneticus (98.2% 16S rRNA gene sequence similarity) and D. burkinensis (97.5% 16S rRNA gene sequence similarity) being its closest relatives among validly described species. A similar phylogenetic affiliation was obtained by sequence analyses of the genes encoding the alpha and the beta subunit of dissimilatory sulphite reductase (dsrAB) as well as the alpha subunit of adenosine-5'-phosphosulphate reductase (apsA) of strain DvO5(T). On the basis of genotypic and phenotypic characteristics, strain DvO5(T) (DSM 16695(T), JCM 12613(T)) is proposed as the type strain of a new species, Desulfovibrio aerotolerans sp. nov.