Two thermophilic, Gram-stain-positive, rod-shaped, non-spore-forming bacteria (strains KI3T and KI4T) were isolated from geothermally heated biofilms growing on a tumulus in the Kilauea Iki pit crater on the flank of Kilauea Volcano (Hawai‘i, USA). Strain KI3T grew over an examined temperature range of 50–70 °C (no growth at 80 °C) and a pH range of 6.0–9.0, with optimum growth at 70 °C and pH 7.0. Strain KI4T grew at temperatures of 55–70 °C and a pH range of 5.8–8.0, with optimum growth at 65 °C and pH 6.7–7.1. The DNA G+C contents of strains KI3T and KI4T were 66.0 and 60.7 mol%, respectively. The major fatty acid for both strains was 12-methyl C18 : 0. Polar lipids in strain KI3T were dominated by glycolipids and phosphatidylinositol, while phosphatidylinositol and phosphoglycolipids dominated in strain KI4T. Strain KI3T oxidized carbon monoxide [6.7±0.8 nmol CO h−1 (mg protein)−1], but strain KI4T did not. 16S rRNA gene sequence analyses determined that the strains belong to the class Thermomicrobia , and that strains KI3T and KI4T are related most closely to Thermomicrobium roseum DSM 5159T (96.5 and 91.1 % similarity, respectively). 16S rRNA gene sequence similarity between strain KI3T and strain KI4T was 91.4 %. Phenotypic features and phylogenetic analyses supported the affiliation of strain KI3T to the genus Thermomicrobium , while results of chemotaxonomic, physiological and biochemical assays differentiated strains KI3T and KI4T from Thermomicrobium roseum . Strain KI3T ( = DSM 27067T = ATCC BAA-2535T) is thus considered to be the type strain of a novel species, for which the name Thermomicrobium carboxidum sp. nov. is proposed. Additionally, the characterization and phylogenetic position of strain KI4T showed that it represents a novel species of a new genus, for which the name Thermorudis peleae gen. nov., sp. nov. is proposed. The type strain of Thermorudis peleae is KI4T ( = DSM 27169T = ATCC BAA-2536T).
A novel acidobacterial strain, Sakura1T, was isolated from pieces of cherry bark. Cells of strain Sakura1T were non-motile, rod-shaped and stained Gram-negative. This strictly aerobic isolate was mesophilic but was able to grow at temperatures as low as 10 °C. Colonies were pink due to production of carotenoids, and its pigmentation was more pronounced in cells grown at lower temperature. This strain had endoglucanase activity. The main respiratory quinone was menaquinone-8, and major cellular fatty acids were iso-C15 : 0, C16 : 1ω7c and C16 : 0. Phylogenetic analysis of 16S rRNA gene sequences revealed that the strain was closely related to species of the genus Granulicella in subdivision 1 of the phylum Acidobacteria . The closest relative was Granulicella paludicola OB1010T (97.1 % 16S rRNA gene sequence similarity). While common characteristics were found among the isolate and species of the genus Granulicella, there were obvious differences between them such as their cell morphology, cellulolytic activity, and tolerance to low temperature and NaCl concentration. Based on phylogenetic and phenotypic findings, a novel species is proposed in the genus Granulicella with the name Granulicella cerasi sp. nov. The type strain is Sakura1T ( = NBRC 107139T = DSM 23641T).
An obligately anaerobic, psychrophilic spirochaete, strain MO-SPC1T, was isolated from a methanogenic microbial community grown in a continuous-flow bioreactor. Originally, this community was obtained from subseafloor sediments off the Shimokita Peninsula of Japan in the north-western Pacific Ocean. The cells were motile, Gram-stain-negative, helical, 0.25–0.55×3.6–15 µm, with a wavelength of approximately 0.5–0.6 µm. Strain MO-SPC1T grew at 0–18 °C (optimally at 15 °C), at pH 6.0–7.5 (optimally at pH 6.8–7.0) and in 20–70 g NaCl l−1 (optimally at 30–40 NaCl l−1). The strain grew chemo-organotrophically with mono-, di- and polysaccharides. The major end products of glucose fermentation were acetate, ethanol, hydrogen and carbon dioxide. The abundant polar lipids of strain MO-SPC1T were diphosphatidylglycerol, phosphatidylglycerol, unknown phospholipids and an unknown lipid. The major cellular fatty acids (>5 % of the total) were C14 : 0, C16 : 0, iso-C13 : 0, iso-C14 : 0, iso-C15 : 0, anteiso-C13 : 0 and anteiso-C15 : 0. To the best of our knowledge, this is the first report of the fatty acids iso-C13 : 0 and anteiso-C13 : 0 from a species of the genus Spirochaeta . Isoprenoid quinones were not found. The G+C content of the genomic DNA was 39.8 mol%. 16S rRNA gene sequence-based phylogenetic analysis showed that strain MO-SPC1T was affiliated with the genus Spirochaeta , and its closest relatives were Spirochaeta isovalerica MA-2T (95.6 % sequence identity) and Spirochaeta litoralis R1T (89.4 %). Based on its phenotypic characteristics and phylogenetic traits, strain MO-SPC1T is placed in a separate taxon at the level of a novel species within the genus Spirochaeta, for which the name Spirochaeta psychrophila sp. nov. is proposed, reflecting its true psychrophilic physiology. The type strain is MO-SPC1T ( = JCM 17280T = DSM 23951T). To our knowledge, this is the first report of an isolate of the phylum Spirochaetes from a deep-sea sedimentary environment, and of an obligately psychrophilic nature.
A facultatively anaerobic, non-pigmented, non-spore-forming bacterium was isolated from a littoral wetland of a boreal lake located on Valaam Island, northern Russia, and designated strain P105T. Cells of this isolate were Gram-negative, non-motile rods coated by S-layers with p2 lattice symmetry. Sugars were the preferred growth substrates. Under anoxic conditions, strain P105T was capable of fermentation and dissimilatory Fe(III) reduction. End products of fermentation were acetate, propionate and H2. Strain P105T was a mildly acidophilic, mesophilic organism, capable of growth at pH 4.0–7.2 (optimum pH 5.5–6.0) and at 4–35 °C (optimum at 20–28 °C). The major fatty acids were iso-C15 : 0 and C16 : 1ω7c; the cells also contained significant amounts of 13,16-dimethyl octacosanedioic acid (isodiabolic acid). The major polar lipids were phosphocholine and phosphoethanolamine; the quinone was MK-8. The G+C content of the DNA was 60.5 mol%. 16S rRNA gene sequence analysis showed that strain P105T belongs to subdivision 3 of the Acidobacteria and is only distantly related (90 % sequence similarity) to the only currently characterized member of this subdivision, Bryobacter aggregatus . The novel isolate differs from Bryobacter aggregatus in its cell morphology and ability to grow under anoxic conditions and in the presence of iron- and nitrate-reducing capabilities as well as quinone and polar lipid compositions. These differences suggest that strain P105T represents a novel genus and species, for which the name Paludibaculum fermentans gen. nov., sp. nov., is proposed. The type strain of Paludibaculum fermentans is P105T ( = DSM 26340T = VKM B-2878T).