A novel moderately thermophilic, organotrophic, microaerophilic, facultatively chemolithotrophic bacterium, designated strain 506T, was isolated from a deep-sea hydrothermal vent site at 13°N in the East Pacific Rise. Cells were Gram-negative, non-motile rods. The organism grew in the temperature range 40–68 °C, with an optimum at 60 °C, and in the pH range 5·5–8·4, with an optimum around pH 7·5. The NaCl concentration for growth was in the range 10–50 g l−1, with an optimum at 30 g l−1. Strain 506T grew chemoorganoheterotrophically with carbohydrates, proteinaceous substrates, organic acids and alcohols using oxygen or nitrate as electron acceptor. Alternatively, strain 506T was able to grow lithoheterotrophically with molecular hydrogen as the energy source. The G+C content of the genomic DNA was 62·9 mol%. Phylogenetic analysis of the 16S rDNA sequence placed strain 506T in the family Thermaceae. On the basis of phenotypic and phylogenetic data, strain 506T (=DSM 14977T=VKM B-2274T) is proposed as the type strain of a novel species in a new genus, Oceanithermus profundus gen. nov., sp. nov.
Among a large collection of South African dairy isolates, a novel Chryseobacterium taxon (DNA group 3) was previously delineated by a polyphasic taxonomic study ( Hugo et al., Syst Appl Microbiol 22, 586–595, 1999 ). In the present paper, this taxon is further characterized using 16S rDNA sequencing, fatty acid methyl ester analysis and a comparative phenotypic analysis, resulting in the proposal of a novel species, Chryseobacterium joostei sp. nov. (type strain Ix 5aT=LMG 18212T=CCUG 46665T).
A novel, obligately anaerobic, mesophilic, haloalkaliphilic spirochaete, strain ASpG1T, was isolated from sediments of the alkaline, hypersaline Mono Lake in California, USA. Cells of the Gram-negative strain were motile and spirochaete-shaped with sizes of 0·2–0·22×8–18 μm. Growth of the strain was observed between 10 and 44 °C (optimum 37 °C), in 2–12 % (w/v) NaCl (optimum 3 % NaCl) and between pH 8 and 10·5 (optimum pH 9·5). The novel strain was strictly alkaliphilic, required high concentrations of carbonates in the medium and was capable of utilizing d-glucose, fructose, maltose, sucrose, starch and d-mannitol. End products of glucose fermentation were H2, acetate, ethanol and formate. Strain ASpG1T was resistant to kanamycin and rifampicin, but sensitive to gentamicin, tetracycline and chloramphenicol. The G+C content of its DNA was 58·5 mol%. DNA–DNA hybridization analysis of strain ASpG1T with its most closely related species, Spirochaeta alkalica Z-7491T, revealed a hybridization value of only 48·7 %. On the basis of its physiological and molecular properties, strain ASpG1T appears to represent a novel species of the genus Spirochaeta, for which the name Spirochaeta americana is proposed (type strain ASpG1T=ATCC BAA-392T=DSM 14872T).
A polyphasic taxonomic study was performed on a novel facultatively anaerobic, hydrogen- or sulfur/thiosulfate-oxidizing, thermophilic chemolithoautotroph recently isolated from subsurface hot aquifer water in a Japanese gold mine. The cells were straight to slightly curved rods, with a single polar flagellum. Growth was observed at 40–70 °C (optimum 60–65 °C; 80 min doubling time) and at pH 6·4–8·8 (optimum pH 7·5). The isolate was unable to use complex organic compounds, carbohydrates, amino acids or organic acids as sole energy and carbon sources. The G+C content of the genomic DNA was 31·3 mol%. Phylogenetic analysis based on 16S rDNA sequences indicated that the isolate was closely related to an uncultivated group of micro-organisms within the order Aquificales obtained from Icelandic and Japanese hot spring microbial mats, but distantly related to previously identified genera of the Aquificales such as Persephonella, Aquifex and Hydrogenobacter. The name Sulfurihydrogenibium subterraneum gen. nov., sp. nov. is proposed for this novel species; the type strain is HGMK1T (=JCM 11477T=ATCC BAA-562T=DSM 15120T).
A novel anaerobic, heterotrophic thermophile was isolated from a deep-sea hydrothermal vent chimney at the Suiyo Seamount in the Izu-Bonin Arc, Japan. The cells were bent, flexible rods, with a single polar flagellum. Growth was observed between 40 and 70 °C (optimum temperature: 60–65 °C; doubling time, 40 min) and between pH 5·0 and 7·5 (optimum pH 6·5). The isolate was a strictly anaerobic heterotroph capable of using complex organic compounds (yeast extract, tryptone, peptone, casein and Casamino acids), ethanol and various organic acids as energy and carbon sources. Hydrogen could serve as a supplementary energy source. Elemental sulfur (S0), nitrate or arsenate was required for growth as an electron acceptor. The G+C content of the genomic DNA was 38·6 mol%. Phylogenetic analysis based on 16S rDNA sequences indicated that isolate SSM1T is closely related to Deferribacter thermophilus BMAT (98·1 %). However, the novel isolate could be clearly differentiated from D. thermophilus BMAT on the basis of its physiological and genetic properties. The name Deferribacter desulfuricans sp. nov. (type strain SSM1T=JCM 11476T=DSM 14783T) is proposed.
Two novel psychrophilic bacterial strains (ZF-6T and ZF-8T) were isolated from the China No. 1 glacier. Polyphasic taxonomy using physiological and biochemical properties and phylogenetic analysis based on 16S rRNA gene sequences showed that the two isolates belonged to the genus Flavobacterium, and that they were distinct from each other and also from the known species of this genus. Strains ZF-6T and ZF-8T are Gram-negative and both have an optimal growth temperature of 11 °C. Strain ZF-6T is able to grow at 0–20 °C, the G+C content of its genomic DNA is 34·4 mol% and the major fatty acids of ZF-6T are C16 : 1 ω7c (17·7 %) and C15 : 1 ω6c (12·7 %). Strain ZF-8T showed a strong ability to degrade organic macromolecules such as starch, CM-cellulose, pectin and chitin. Its DNA G+C content is 35·1 mol%, and the major fatty acids are C16 : 1 ω7c (18·2 %) and C15 : 0 (9·9 %). Phylogenetic analysis based on 16S rDNA sequences indicated that ZF-6T and ZF-8T belong to the genus Flavobacterium and represent two novel species. DNA–DNA hybridization also supported the status of the two new isolates. The names Flavobacterium xinjiangense sp. nov. (type strain, ZF-6T=AS 1.2749T=JCM 11314T) and Flavobacterium omnivorum sp. nov. (type strain, ZF-8T=AS 1.2747T=JCM 11313T) are proposed for the two new isolates.
A novel thermophilic, hydrogen-oxidizing bacterium, designated 29WT, was isolated from a deep-sea hydrothermal vent chimney sample collected from the Suiyo Seamount in the Izu-Bonin Arc, Japan, at a depth of 1385 m. The cells were cocci (0·9–1·0 μm in diameter) and straight rods (2·3–2·7 μm long) under static and agitated culture conditions, respectively. The new isolate was an obligate chemolithoautotroph growing by respiratory nitrate reduction with H2, forming N2 as a final product. A very low concentration of O2 (optimum 0·6–0·8 %, v/v) was also used as an alternative electron acceptor while reduced sulfur compounds did not serve as electron donors. Anoxic hydrogen-oxidizing growth with nitrate was observed between 50 and 72·5 °C (optimum 70 °C; 40 min doubling time), pH 5·5 and 7·6 (optimum pH 7·2), and in the presence of 1·5 and 5·0 % NaCl (optimum 2·5 %). The G+C content of the genomic DNA was 37·3 mol%. Phylogenetic analysis based on 16S rDNA sequences indicated that the isolate was a member of the recently described genus Persephonella in a potential new family within the order Aquificales. On the basis of the physiological and molecular properties of the new isolate, the name Persephonella hydrogeniphila sp. nov. is proposed. The type strain is strain 29WT (=JCM 11663T=DSM 15103T).