A mesophilic, Gram-stain-positive, spore-forming bacterium that formed branched mycelia was isolated from paddy soil in Gunung Salak (Mount Salak), West Java, Indonesia. This strain, designated S-27T, grew at temperatures between 20 and 37 °C; the optimum growth temperature was 25 to 30 °C, and no growth was observed at 15 or 45 °C. The pH range for growth was pH 3.5 to 8.6; the optimum pH was 6.0, and no growth was observed at pH 3.0 or 9.2. Strain S-27T was able to hydrolyse polysaccharides such as starch, cellulose and xylan. The G+C content of the DNA of strain S-27T was 55.7 mol%. The major fatty acids were iso-C17 : 0 and C16 : 1 2-OH, and the major menaquinone was MK-9 (H2). The cell wall of strain S-27T contained d-glutamic acid, glycine, l-alanine, d-alanine, l-ornithine and β-alanine in a molar ratio of 1.0 : 1.6 : 1.4 : 0.6 : 0.9 : 1.1. The polar lipids consisted of phosphatidylglycerol, phosphatidylinositol and two glycolipids. The major cell-wall sugar was arabinose. Detailed phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S-27T belongs to the order Ktedonobacterales and is most closely related to Ktedonobacter racemifer SOSP1-21T (89.6 % sequence identity). On the basis of its chemotaxonomic and phenotypic features and phylogenetic position, we concluded that strain S-27T represents a novel genus and species, for which we propose the name Dictyobacter aurantiacus gen. nov., sp. nov. The type strain of Dictyobacter aurantiacus is strain S-27T (=NBRC 109595T=InaCC B312T). Emendation of the description of the genus Thermosporothrix is also provided.
A slightly thermophilic, aerobic bacterium, designated YIM 72257T, was isolated from a sediment sample taken from a hot spring in Tengchong county, Yunnan province, south-west China. The isolate was Gram-stain-negative, non-sporulating and forms non-motile rods, appearing in chains. The isolate grew at 50–65 °C, pH 6.0–9.0 and with 0.5–1 % NaCl (w/v). 16S rRNA gene sequence analysis showed that strain YIM 72257T was most closely related to Meiothermus cateniformans LY1T (95.6 %), Meiothermus ruber DSM 1279T (95.1 %) and Meiothermus taiwanensis WR-30T (94.6 %). The genomic DNA G+C content of strain YIM 72257T was 62.6 mol%. The main cellular fatty acids (>5 %) were anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0, iso-C17 : 0, iso-C15 : 0 and C16 : 0. The polar lipids consisted of an uncharacterized phospholipid and two glycolipids. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strain YIM 72257T is proposed to be a representative of a novel species of the genus Meiothermus , for which the name Meiothermus luteus sp. nov. is proposed. The type strain is YIM 72257T (=KCTC 52599T=CCTCC AB 2017100T).
A thermophilic bacterial strain, designated YIM 73026T was isolated from a sediment sample collected from a hot spring in Tibet, PR China. The taxonomic position of the novel isolate was investigated by a polyphasic approach. The novel isolate was Gram-stain-negative, aerobic and rod-shaped. Colonies were circular, convex, opaque and yellow. The strain grew at 50–70 °C (optimum, 60 °C), pH 6.0–8.0 (optimum, pH 7.0) and in the presence of up to 1.0 % NaCl (w/v). Comparison of the 16S rRNA gene sequences of YIM 73026T and those of other members of the genus Thermus showed sequence similarities ranging from 91.2 to 97.5 %, with YIM 73026T showing closest sequence similarity to Thermus scotoductus SE-1T (97.5 %). DNA–DNA hybridization results, however, revealed that DNA–DNA reassociation values between YIM 73026T and T. scotoductus DSM 8553T (37.6 %), Thermus amyloliquefaciens YIM 77409T (34.5 %), Thermus antranikianii DSM 12462T (30.3 %), Thermus caliditerrae YIM 77925T (28.6 %) and Thermus tengchongensis YIM 77924T (27.3 %) were well below the 70 % limit for species identification. YIM 73026T contained MK-8 as the respiratory quinone, and iso-C15 : 0, iso-C16 : 0, iso-C17 : 0 and anteiso-C15 : 0 as the major cellular fatty acids (>10 %). The polar lipids consisted of one aminophospholipid, one phospholipid and two glycolipids. The genomic DNA G+C content of YIM 73026T was 65.4 mol%. On the basis of morphological, chemotaxonomic and genotypic characteristics, it is proposed that the isolate represents a novel species of the genus Thermus , for which the name Thermus caldifontis sp. nov. is proposed. The type strain is YIM 73026T (=NBRC 112415T=CCTCC AB 2016305T).