Chelatococcus albus sp. nov., a bacterium isolated from hot spring microbial mat.

A Gram-stain-negative, non-endospore-forming, motile, short rod-shaped strain, designated SYSU G07232T, was isolated from a hot spring microbial mat, sampled from Rehai National Park, Tengchong, Yunnan Province, south-western China. Strain SYSU G07232T grew at 25-50 °C (optimum, 37 °C), at pH 5.5-9.0 (optimum, pH 6.0) and tolerated NaCl concentrations up to 1.0 % (w/v). Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain SYSU G07232T showed closest genetic affinity with Chelatococcus daeguensis K106T. The genomic features and taxonomic status of this strain were determined through whole-genome sequencing and a polyphasic approach. The predominant quinone of this strain was Q-10. Major cellular fatty acids comprised C19 : 0 cyclo ω8c and summed feature 8. The whole-genome length of strain SYSU G07232T was 4.02 Mbp, and the DNA G+C content was 69.26 mol%. The average nucleotide identity (ANIm ≤84.85 % and ANIb ≤76.08  %) and digital DNA-DNA hybridization (≤ 21.9 %) values between strain SYSU G07232T and the reference species were lower than the threshold values recommended for distinguishing novel prokaryotic species. Thus, based on the provided phenotypic, phylogenetic, and genetic data, it is proposed that strain SYSU G07232T (=KCTC 8141T=GDMCC 1.4178T) be designated as representing a novel species within the genus Chelatococcus, named Chelatococcus albus sp. nov.

Thermomonas flagellata sp. nov. and Thermomonas alba sp. nov., two novel members of the phylum Pseudomonadota isolated from hot spring sediments.

Two novel species, designated strains SYSU G04041T and SYSU G04536T, were isolated from hot spring sediments collected in Yunnan, PR China. Phenotypic and chemotaxonomic analyses, and whole-genome sequencing were used to determine the taxonomic positions of the candidate strains. Phylogenetic analysis using 16S rRNA gene sequence indicated that strain SYSU G04041T showed the highest sequence similarity to Thermomonas haemolytica A50-7-3T (97.5 %), and SYSU G04536T showed the highest sequence similarity to Thermomonas hydrothermalis SGM-6T (98.2 %). The strains could be differentiated from other species of the genus Thermomonas by their distinct phenotypic and genotypic characteristics. Cells of strains SYSU G04041T and SYSU G04536T were aerobic, motile and Gram-stain-negative. Growth both occurred optimally at 45 °C and pH 7.0 for SYSU G04041T and SYSU G04536T. In addition, the predominant respiratory quinone in both isolates was ubiquinone Q-8. The major fatty acids (>10 %) of strain SYSU G04041T were C16 : 0, iso-C15 : 0 and iso-C16 : 0, while the major fatty acids (>10 %) of strain SYSU G04536T were iso-C15 : 0 and iso-C16 : 0. The main detected polar lipids in strains SYSU G04041T and SYSU G04536T included phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The G+C contents of the genomic DNA of strains SYSU G04041T and SYSU G04536T based on draft genomic sequences were 72.5 and 68.3 %, respectively. On the basis of phenotypic, genotypic and phylogenetic data, strains SYSU G04041T and SYSU G04536T represent two novel species of the genus Thermomonas, for which the names Thermomonas flagellata sp. nov. and Thermomonas alba sp. nov. are proposed, with the type strains SYSU G04041T (=CGMCC 1.19366T=KCTC 92228T) and SYSU G04536T (=CGMCC 1.19367T=KCTC 82839T), respectively.

Rhodoflexus caldus gen. nov., sp. nov., a new member of the phylum Bacteroidota isolated from a hot spring sediment.

A thermophilic bacterium, designated strain SYSU G04325T, was isolated from a hot spring sediment in Yunnan, China. Polyphasic taxonomic analyses and whole-genome sequencing were used to determine the taxonomic position of the strain. Phylogenetic analysis using 16S rRNA gene sequences indicated that strain SYSU G04325T shows high sequence similarity to Thermoflexibacter ruber NBRC 16677T (86.2%). The strain can be differentiated from other species of the family Thermoflexibacteraceae by its distinct phenotypic and genotypic characteristics. Cells of the strain SYSU G04325T were observed to be aerobic, Gram-stain negative and filamentous. Growth was found to occur optimally at 45 ºC and pH 7.0. In addition, the respiratory quinone was identified as menaquinone-7, while the major fatty acids (> 10%) were identified as iso-C15:0, iso-C17:0 and Summed Feature 9 (iso-C17:1ω9c). The polar lipids detected included phosphatidylethanolamine, three unidentified phospholipids, one unidentified glycolipid, five unidentified aminolipids and four unidentified polar lipids. The G + C content of the genomic DNA was determined to be 47.6% based on the draft genome sequence. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU G04325T is concluded to represent a novel species of a novel genus in the family Thermoflexibacteraceae, for which the name Rhodoflexus caldus gen. nov., sp. nov. is proposed. The type strain of Rhodoflexus caldus is SYSU G04325T (= MCCC 1K06127T = KCTC 82848T).

Thermus brevis sp. nov., a moderately thermophilic bacterium isolated from a hot spring microbial mat.

Three closely related, facultative anaerobic, Gram-stain-negative, twitching motile, short rod-shaped, non-endospore-forming, moderately thermophilic bacteria, designated strains SYSU G05001T, SYSU G05003 and SYSU G05004, were isolated from a hot spring microbial mat, collected from Rehai National Park, Tengchong, Yunnan Province, south-western China. The results of phylogenetic analysis based on the 16S rRNA gene sequences indicated that these three strains were closely related to Thermus scotoductus SE-1T (97.97, 98.18, 97.90 % sequence similarity). Whole genome sequencing and polyphasic taxonomic approach were used to determine the genomic profile and taxonomic status of the novel strain SYSU G05001T. Cell growth occurred at 37-80 °C (optimum, 55 °C), pH 6.0-8.0 (optimum, pH 7.0) and with 0-3.0 % (w/v) NaCl (optimum, 1%). Thiosulfate enhanced cell growth. MK-8 was the predominant menaquinone. The major cellular fatty acids included iso-C15 : 0, iso-C17 : 0 and anteiso-C15 : 0. The major polar lipids were consisted of aminophospholipid, glycolipid and phospholipids. The whole genome of strain SYSU G05001T consisted of 2.55 Mbp and the DNA G+C content was 64.94 mol%. The average nucleotide identity (≤94.95 %) and digital DNA-DNA hybridization (≤62.3 %) values between strain SYSU G05001T and other members of the genus Thermus were all lower than the threshold values recommended for distinguishing novel prokaryotic species. On the basis of the presented polyphasic evidence and genotypic data, it is proposed that strain SYSU G05001T (=KCTC 82627T=MCCC 1K06118T) represents a novel species of the genus Thermus, for which the name Thermus brevis sp. nov. is proposed.

Caldovatus aquaticus sp. nov., a moderately thermophilic bacterium isolated from hot spring microbial mat.

Two closely related, aerobic, Gram-stain-negative, motile, oval-shaped, non-endospore-forming, moderately thermophilic bacteria, designated strains SYSU G05006T and SYSU G05005, were isolated from a bioreactor enrichment and the original sample was collected from Rehai National Park, Tengchong, Yunnan Province, PR China. The results of phylogenetic analysis based on the 16S rRNA gene sequences indicated that these two strains were closely related to Caldovatus sediminis YIM 72346T (96.75 and 96.89 % sequence similarity, respectively). The whole genome size of strain SYSU G05006T was 3.87 Mbp with a DNA G+C content of 75.33 mol%. The average nucleotide identity (ANI based on the MUMmer algorithm≤90.31 % and ANI based on blast≤89.36 %) and digital DNA-DNA hybridization (≤35.10 %) values between strain SYSU G05006T and other members of the family Acetobacteraceae were all lower than the threshold values recommended for distinguishing novel prokaryotic species. Optimal growth of the strain was observed at 55 °C and pH 6.0. Ubiquinone-10 was the predominant respiratory lipoquinone. The major cellular fatty acids included iso-C14 : 0, C16 : 1 ω5c, summed feature 5 and summed feature 7. The major polar lipids consisted of diphosphatidylglycerol, one unidentified aminolipid, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified phospholipids and two unidentified lipids. Based on results of phylogenetic analyses, comparative genomics and phenotypic characteristics, we describe a new species of the genus Caldovatus represented by strain SYSU G05006T (=KCTC 82831T=MCCC 1K06125T), for which we propose the name Caldovatus aquaticus sp. nov.

Thermaurantiacus tibetensis gen. nov., sp. nov., a novel moderately thermophilic bacterium isolated from hot spring microbial mat in Tibet.

Two bacterial strains SYSU G02173T and SYSU G03142 were isolated from hot springs in Tibet, China. Based on the results of nearly full-length 16S rRNA gene sequences and phylogenetic analyses, strains SYSU G02173T and SYSU G03142 were assigned to the family Sphingosinicellaceae, and were closest to Sandaracinobacter sibiricus RB16-17 T (96.04% and 96.12% similarity, respectively). Cells of the both new strains were observed to be motile rod-shape, Gram-staining negative. Growth occurred at pH 6-8 (optimal: pH 7.0) and 37-55 °C (optimal: 45 °C) with 0-1.0% (w/v) NaCl in T4 broth. The cells were found to be positive for oxidase and catalase activities. The major respiratory ubiquinone was Q-8. The major fatty acids were identified as summed feature 8 (C18:1 ω7c and/or C18:1 ω6c), C16:0, C14:0 2-OH. The major polar lipids were found to consist of sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, one unidentified phospholipid, one unidentified glycolipid, three unidentified aminolipids and two unidentified polar lipids. The DNA G + C contents of strains SYSU G02173T and SYSU G03142 were 71.8%. The average nucleotide identity (ANI) value between strain SYSU G02173T and SYSU G03142 was 99.98%. The amino acid identity (AAI) values between them and their closely related species were below 66.14%. The isolates are characterized by aerobic growth, a yellow endocellular pigment and a higher optimum growth temperature. The results showed that strains SYSU G02173T and SYSU G03142 represent a novel species of a novel genus in the family Sphingomonadaceae, and thus the name Thermaurantiacus tibetensis (type strain SYSU G02173T = KCTC 72052 T = CGMCC 1.16680 T) is proposed.

Rhabdaerophilum calidifontis gen. nov., sp. nov., a novel bacterium isolated from a hot spring, and proposal of Rhabdaerophilaceae fam. nov.

A novel thermotolerant bacterial strain was isolated from a hot spring in a Tibetan geothermal field. Phylogenetic analysis of the 16S rRNA gene sequence of the novel strain showed that it belongs to a distinct lineage far from any known taxa. The new isolate shared the highest pairwise sequence identity with Phreatobacter cathodiphilus S-12T (92.8 % similarity) according to the 16S rRNA gene sequences. Cells were Gram-stain-negative, aerobic, rod-shaped and formed white round colonies. The strain grew at the ranges of 28-45 °C (optimum, 37 °C), pH 5.0-7.0 (optimum, pH 6.0) and 0-2 % NaCl. The strain was positive for catalase and oxidase. The major respiratory quinone was ubiquinone Q-10. Polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylcholine. The major fatty acids were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The DNA G+C content was 68.3 mol%. Based on these distinguishing properties, this strain is proposed to represent a new species of a new genus Rhabdaerophilum calidifontis gen. nov., sp. nov., within a new family Rhabdaerophilaceae fam. nov. The type strain of the type species of Rhabdaerophilum calidifontis is SYSU G02060T (=KCTC 72351T=CGMCC 1.17070T).

Marmoricola caldifontis sp. nov., a novel actinobacterium isolated from a hot spring.

A Gram-staining-positive, aerobic, non-motile, non-spore-forming and coccoid-shaped actinobacterial strain, designated YIM 730233T, was isolated from a sediment sample, collected from a hot spring in Tibet, China. Colonies were brownish, circular, smooth and convex. Strain YIM 730233T was able to grow in the temperature range of 20-50 °C, pH 6.5-8.0 and in the presence of up to 1.0 % (w/v) NaCl. A comparison of the 16S rRNA gene sequence of strain YIM 730233T with sequences of type strains of most closely related species of Marmoricola showed highest sequence similarities to Marmoricola bigeumensis MSL-05T (98.3%) and Marmoricola pocheonensis Gsoil 818T (98.1%). The draft genome of strain YIM 730233T had a size of 4 806 234 bp with a DNA G+C content of 72.1 mol%. The major fatty acids (>10 %) of strain YIM 730233T mainly consisted of iso-C16 : 0, anteiso-C17 : 0 and C18 : 1 ω9c, typical of the genus Marmoricola. Strain YIM 730233T had LL-2,6-diaminopimelic acid as the diagnostic diamino acid in the cell wall. The predominant isoprenoid quinone was MK-8(H4). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids and an unidentified lipid. DNA-DNA hybridizations between strain YIM 730233T and type strains of Marmoricola bigeumensis MSL-05T and Marmoricola pocheonensis Gsoil 818T resulted in similarity values of 21 and 19% respectively. Based on DNA-DNA hybridization results, together with the differentiating biochemical and chemotaxonomic features, showed that strain YIM 730233T represents a novel Marmoricola species, for which the name Marmoricola caldifontis sp. nov. (type strain YIM 730233T=KCTC 49192T=CGMCC 4.7521T), is proposed.

Rhodobacter flagellatus sp. nov., a thermophilic bacterium isolated from a hot spring.

A thermophilic bacterium, designated SYSU G03088T, was isolated from Moincer hot spring, Tibet, PR China. Polyphasic taxonomic analyses and whole-genome sequencing were used to determine the taxonomic position and genomic profiles of the strain. Phylogenetic analysis using 16S rRNA gene sequence indicated that SYSU G03088T showed highest sequence similarity to Rhodobacter blasticus CGMCC 1.3365T (96.0 % sequence identity). The strain could be differentiated from most recognized species of the genus Rhodobacter by its slightly purple colony colour, distinct phenotypic characters and low ANI values. Cells were Gram-staining negative, and oval-to-rod shaped. Poly-ß-hydroxybutyrate and vesicular intracytoplasmic membrane structures were formed inside cells. Growth occurred optimally at 45 °C and pH 7.0. Ubiquinone 10 was the only respiratory quinone. The major fatty acids (>10 %) were C18 : 0, C18 : 1ω7c 11-methyl and summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The detected polar lipids of SYSU G03088T included diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylmethylethanolamine. The DNA G+C content of SYSU G03088T was 67.7 % (genome). On the basis of the differences in the phenotypic characteristics and phylogenetic analyses, SYSU G03088T is considered to represent a novel species of the genus Rhodobacter, for which the name Rhodobacter flagellatus sp. nov. is proposed. The type strain is SYSU G03088T (=CGMCC 1.16876T=KCTC 72354T).

Thermus caldilimi sp. nov., a thermophilic bacterium isolated from a geothermal area.

A Gram-stain negative, aerobic bacterium, designated strain YIM 78456T, was isolated from a hot spring sediment, Ngamring county, Tibet, south-west China. The taxonomic position of the isolate was investigated by a polyphasic approach. The novel isolate was found to be aerobic and rod-shaped. Colonies were observed to be pale yellow and circular. The strain was found to grow at pH 7.0-8.0 (optimum, pH 7.0), 45-65 °C (optimum, 55 °C) and in the presence of up to 1.5% NaCl. Comparison of the 16S rRNA gene sequence of strain YIM 78456T and other members of the genus Thermus showed sequence similarities ranging from 90.3 to 97.3%, with strain YIM 78456T showing close sequence similarity to Thermus caliditerrae YIM 77925T (97.3%). The phylogenetic trees based on 16S rRNA gene sequences showed that strain YIM 78456T forms a distinct clade with T. caliditerrae YIM 77925T. The predominant menaquinone was identified as MK-8 and the DNA G+C content was determined to be 65.1 mol%. The major cellular fatty acids (> 10%) were identified as iso-C15:0, anteiso-C15:0 and iso-C17:0. The polar lipids were found to consist of an aminophospholipid, a phospholipid and glycolipids. On the basis of the morphological and chemotaxonomic characteristics, as well as genotypic data, it is proposed that strain YIM 78456T represents a novel species of the genus Thermus, for which the name Thermus caldilimi sp. nov. is proposed. The type strain is YIM 78456T (= KCTC 52948T = NBRC 113036T).

Novosphingobium meiothermophilum sp. nov., isolated from a hot spring.

A moderately thermophilic, aerobic, Gram-stain-negative, non-spore-forming, rod-shaped and yellow-pigmented bacterium, designated strain SYSU G00007T, was isolated from a hot spring slurry sample. Optimum growth was observed at 37-45 °C and pH 7. Pairwise comparison of the 16S rRNA gene sequence of strain SYSU G00007T and other Novosphingobium species showed sequence similarities ranging from 93.7 to 97.9 %. Strain SYSU G00007T showed highest sequence identity to Novosphingobium subterraneum DSM 12447T (97.9 %). The average nucleotide identities and digital DNA-DNA hybridization values between strain SYSU G00007T and its closely related phylogenetic neighbours were below 81 and 31 %, respectively, indicating that strain SYSU G00007T represented a novel species of the genus Novosphingobium. The DNA G+C content of strain SYSU G00007T was 64.3 % (genome). The major respiratory quinone was ubiquinone Q-10. The polar lipid profile included diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, two sphingoglycolipids, two unidentified phospholipids, two unidentified aminophospholipids and two unidentified polar lipids. Spermidine was the only polyamine detected. The major fatty acids were C19 : 0cyclo ω8c, summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0. The results obtained from phylogenetic, chemotaxonomic and phenotypic analyses support the conclusion that strain SYSU G00007T represents a novel species of the genus Novosphingobium, for which we proposed the name Novosphingobiummeiothermophilum sp. nov. The type strain is SYSU G00007T (=KCTC 52672T=CCTCC AB2017010T).

Calidifontimicrobium sediminis gen. nov., sp. nov., a new member of the family Comamonadaceae.

Two Gram-stain-negative and facultative anaerobic bacteria, designated strains SYSU G00088T and YIM 73032, were isolated from sediment samples collected from hot springs in Tibet, China. Based on the analyses of the 16S rRNA gene sequences, the two isolates were observed to be a member of the family Comamonadaceae, sharing highest pairwise sequence identity with type strains of Piscinibacter defluvii SH-1T (97.8  and 97.7 %, respectively). They were able to grow in the temperature range of 37-50 °C, pH 5.0-9.0 and in the presence of up to 0.5 % (w/v) NaCl. Both strains were positive for catalase and oxidase reactions. Cells of the novel isolates were short-rods and motile by means of a polar flagellum. The chemotaxonomic features of the two strains include ubiquinone 8 as the respiratory isoprenologue, diphosphatidylglycerol, phosphatidylethanolamine and phoshatidylglycerol as the known polar lipids, and C16 : 0 and C17 : 0cyclo as major fatty acids. The genomic DNA of strains SYSU G00088T and YIM 73032 had G+C contents of 71.8 and 71.9%, respectively. Based on the analyses of the phylogenetic, chemotaxonomic, morphological and genomic data, the two isolates are considered to represent a novel species of a new genus, for which the name Calidifontimicrobium sediminis gen. nov., sp. nov. is proposed. The type strain of Calidifontimicrobium sediminis is SYSU G00088T (=KCTC 52671T=CGMCC 1.13597T).

Rhabdothermincola sediminis gen. nov., sp. nov., a new actinobacterium isolated from hot spring sediment, and emended description of the family Iamiaceae.

One thermophilic bacterium, designated strain SYSU G02662T, was isolated from hot spring sediment sampled in Tibet, PR China. Polyphasic taxonomic analyses and whole-genome sequencing were used to determine the taxonomy position of the strain. Phylogenetic analysis using 16S rRNA gene sequences indicated that strain SYSU G02662T showed the highest sequence similarity to Actinomarinicola tropica SCSIO 58843T (95.1 %). The strain could be differentiated from other species of the family Iamiaceae by its distinct phenotypic and genotypic characteristics. Cells of strain SYSU G02662T were aerobic, Gram-staining-positive and short rodshaped. Growth occurred optimally at 45 °C and pH 7.0. In addition, meso-diaminopimelic acid was the diagnostic diamino acid in the cell-wall peptidoglycan. The respiratory quinone was MK-9 (H8), while the major fatty acids (>10 %) were C16 : 0, C17 : 0, C18 : 0 and iso-C16 : 0. The detected polar lipids included diphosphatidylglycerol, phosphatidylinositol mannoside and phosphatidylinositol. The G+C content of the genomic DNA was 70.5 % based on the draft genomic sequence. On the basis of phenotypic, genotypic and phylogenetic data, strain SYSU G02662T represents a novel species of a novel genus in the family Iamiaceae, for which the name Rhabdothermincola sediminis gen. nov., sp. nov. is proposed. The type strain of the proposed novel species is SYSU G02662T (=CGMCC 4.7688T=KCTC 49500T).

Thermus sediminis sp. nov., a thiosulfate-oxidizing and arsenate-reducing organism isolated from Little Hot Creek in the Long Valley Caldera, California.

Thermus species are widespread in natural and artificial thermal environments. Two new yellow-pigmented strains, L198T and L423, isolated from Little Hot Creek, a geothermal spring in eastern California, were identified as novel organisms belonging to the genus Thermus. Cells are Gram-negative, rod-shaped, and non-motile. Growth was observed at temperatures from 45 to 75 °C and at salinities of 0-2.0% added NaCl. Both strains grow heterotrophically or chemolithotrophically by oxidation of thiosulfate to sulfate. L198T and L423 grow by aerobic respiration or anaerobic respiration with arsenate as the terminal electron acceptor. Values for 16S rRNA gene identity (≤ 97.01%), digital DNA-DNA hybridization (≤ 32.7%), OrthoANI (≤ 87.5%), and genome-to-genome distance (0.13) values to all Thermus genomes were less than established criteria for microbial species. The predominant respiratory quinone was menaquinone-8 and the major cellular fatty acids were iso-C15:0, iso-C17:0 and anteiso-C15:0. One unidentified phospholipid (PL1) and one unidentified glycolipid (GL1) dominated the polar lipid pattern. The new strains could be differentiated from related taxa by ß-galactosidase and ß-glucosidase activity and the presence of hydroxy fatty acids. Based on phylogenetic, genomic, phenotypic, and chemotaxonomic evidence, the novel species Thermus sediminis sp. nov. is proposed, with the type strain L198T (= CGMCC 1.13590T = KCTC XXX).

Physiological and genomic properties of Thermus tenuipuniceus sp. nov., a novel slight reddish color member isolated from a terrestrial geothermal spring.

Two closely related, thermophilic bacteria, designated strains YIM 76954T and YIM 76947, were isolated from the Rehai Geothermal Field, Tengchong, Yunnan province, south-west China. Polyphasic approach and whole genome sequencing were used to determine the taxonomy status and genomic profiles of the novel strains. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two isolates were closely related to Thermus scotoductus SE-1T (97.1% sequence similarity), and T. amyloliquefaciens YIM 77409T (96.6%). The strains could be differentiated from most recognized Thermus species by their whitish to slight reddish colony color, distinct DNA fingerprinting profiles and low ANI values. Cells stained Gram-negative, rod-shaped of diameter 0.2-0.5µm and length 1.5-5.0µm. Growth occurred at 50-75°C, pH 6.0-9.0 and in the presence of up to 1.0% (w/v) NaCl concentration. Thiosulfate was found to enhance cell growth, besides improving the intensity of its colony color. Oxygen, nitrate, sulfur, and Fe(III) could be used as terminal electron acceptors for growth. MK-8 was the major respiratory menaquinone. Major fatty acids were iso-C17:0, iso-C15:0, anteiso-C17:0, and anteiso-C15:0. The genome size was 2.26Mbp with 65.5% average GC content. A total of 2374 genes was predicted, comprising 2322 protein-coding and 52 RNA genes. On the basis of the polyphasic evidence presented, it is proposed that strain YIM 76954T represents a novel species of the genus Thermus, for which the name Thermus tenuipuniceus sp. nov. is proposed. The type strain is YIM 76954T (=JCM 30350T=KCTC 4677T).

Rhabdanaerobium thermarum gen. nov., sp. nov., a novel anaerobic bacterium isolated from a hot spring.

A novel Gram-stain-positive, obligately anaerobic and thermophilic bacterium, strain SYSU GA15001T, was isolated from a sample collected from a hot spring located in Tengchong, China. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain SYSU GA15001T belonged to the family Eubacteriaceae, and was closely related to 'Irregularibacter muris' 2PG-426-CC4.2T (93.6 % similarity), Garciella nitratireducens DSM 15102T (93.2 %) and Alkalibacter saccharofermentans Z-78920T (89.7 %). Cells were rods and motile by means of a subpolar flagellum. Spores were formed in old cultures. Optimum growth was observed at 45 °C, at pH 7 and in the presence of 1.5 % (w/v) NaCl. The strain utilized d-arabinose, dulcitol, d-galactose, glucose, lactose, maltose, d-mannose, raffinose, l-rhamnose, d-sorbitol, xylitol, l-alanine, l-arginine, glycine, l-isoleucine, l-leucine, dl-methionine, NH4Cl, l-proline and l-threonine as sole carbon/nitrogen sources. Additionally, complex substrates including beef extract, peptone, starch and yeast extract can also be used as sole energy sources. The major fatty acid methyl esters were C14 : 0, anteiso-C15 : 0 and C18 : 0. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, an unidentified polar lipid, three unidentified phospholipids and an unidentified glycolipid. The DNA G+C content was determined to be 35.6 mol%. Strain SYSU GA15001T was physiologically and phylogenetically distinguishable from its closely related genera, and merits assignment as representing the type species of a new genus Rhabdanaerobium, with the name Rhabdanaerobium thermarum gen. nov., sp. nov. The type strain of the type species is SYSU GA15001T (=CGMCC 1.5219T=KCTC 15623T).

Thermus caldifontis sp. nov., a thermophilic bacterium isolated from a hot spring.

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 %), Thermusamyloliquefaciens YIM 77409T (34.5 %), Thermusantranikianii DSM 12462T (30.3 %), Thermuscaliditerrae YIM 77925T (28.6 %) and Thermustengchongensis 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).

Altererythrobacter lauratis sp. nov. and Altererythrobacter palmitatis sp. nov., isolated from a Tibetan hot spring.

Two Gram-negative, moderately thermophilic, yellow-pigmented, rod-shaped and motile bacterial strains, designated YIM 75003T and YIM 75004T, were isolated from sediment samples collected from the Tagejia hot spring in Tibet, western China. The taxonomic affiliation of the two strains was investigated by a polyphasic approach. Pairwise comparison of the 16S rRNA gene sequences showed that strains YIM 75003T and YIM 75004T are closely related to Altererythrobacter buctense M0322T (97.2 and 97.1% respectively), while sharing 99.9% sequence similarity against each other. Optimum growth of the two strains was observed at 37-45 °C, pH 8.0 and in the presence of 1-6% NaCl (w/v). Their predominant respiratory quinone was found to be ubiquinone 10. The major fatty acids in both the strains were identified as summed feature 8 (C18:1 ω6c and/or C18:1 ω7c) and summed feature 4 (C17:1 anteiso B and/or iso I). Their major polar lipid profiles were found to be diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and sphingoglycolipid. The DNA G+C contents of strains YIM 75003T and YIM 75004T were determined to be 61.3 and 60.1 mol%, respectively. The DNA-DNA hybridization values between strains YIM 75003T and YIM 75004T, and between the two strains and their closely related phylogenetic neighbour A. buctense M0322T (=CGMCC 1.12871T) were less than 70%. Based on the morphological and physiological properties, phylogenetic analyses, chemotaxonomic characteristics and DNA-DNA relatedness values, the two strains can be distinguished from each other and from their phylogenetically closely related strain. Strains YIM 75003T and YIM 75004T are, therefore, considered to represent two novel species of the genus Altererythrobacter, for which the names Altererythrobacter lauratis sp. nov. (type strain YIM 75003T = KCTC 52606T = CCTCC AB2016268T) and Altererythrobacter palmitatis sp. nov. (type strain YIM 75004T = KCTC 52607T = CCTCC AB2016270T) are proposed.

Tibeticola sediminis gen. nov., sp. nov., a thermophilic bacterium isolated from a hot spring.

Two closely related thermophilic bacterial strains, designated YIM 73013T and YIM 73008, were isolated from a sediment sample collected from a hot spring in Tibet, western Tibet province, China. The taxonomic positions of the two isolates were investigated using a polyphasic approach. The novel isolates were Gram-stain-negative, aerobic, short-rod-shaped and motile by means of a polar flagellum. They were oxidase- and catalase-positive and were able to grow at 30-55 °C (optimum, 37-45 °C), at pH 6.0-8.0 (optimum, pH 7.0) and with NaCl tolerance up to 1 % (w/v). Phylogenetic analyses based on 16S rRNA gene sequences showed that strains YIM 73013T and YIM 73008 formed a distinct lineage with respect to closely related genera in the family Comamonadaceae and shared highest 16S rRNA gene sequences similarities with Acidovorax caeni R-24608T (96.3 and 96.4 %, respectively). The respiratory quinone was ubiquinone-8 (Q-8) and the major cellular fatty acids observed were C17 : 1ω6c, C16 : 0 and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The genomic DNA G+C contents of strains YIM 73013T and YIM 73008 were 68.7 and 68.3 mol%, respectively. Based on the morphological, phylogenetic and chemotaxonomic results, the two isolates represent a novel species in a new genus, for which the name Tibeticola sediminis gen. nov., sp. nov. is proposed. The type strain of Tibeticola sediminis is YIM 73013T (=DSM 101684T=KCTC 42873T).

Deinococcus saudiensis sp. nov., isolated from desert.

Two gamma- and UV-radiation-resistant, pink-coloured bacterial strains, designated YIM F302T and YIM F235, were isolated from the desert of Yanbu' al Bahr located in west of Saudi Arabia. Taxonomic positions of the two isolates were investigated by polyphasic taxonomic approaches. Cells of the two strains were Gram-stain-negative, aerobic and rod-shaped. They were able to grow at 15-45 °C and pH 6.0-8.0 and had a NaCl tolerance limit of 1 % (w/v). Phylogenetic analyses based on 16S rRNA gene sequences revealed that strains YIM F302T and YIM F235 represent members of the genus Deinococcus, sharing highest sequence similarities of 98.3 and 98.4 %, respectively, with Deinococcus grandis DSM 3963T. The strains were found to contain MK-8 as the respiratory menaquinone. Major fatty acids (>10 %) of the two strains were C15 : 1ω6c, C16 : 0 and C16 : 1ω7c. DNA-DNA hybridization values of the two isolates against the closely related type strains were significantly below the 70 % limit for species delineation. Genomic DNA G+C contents of strains YIM F302T and YIM F235 were 69.3 and 69.0 mol%, respectively. Based on the phenotypic and genotypic characteristics recorded, it is determined that the two isolates represent a novel species of the genus Deinococcus, for which the name Deinococcus saudiensis sp. nov. is proposed. The type strain is YIM F302T (=CGMCC 1.15089T=DSM 29933T).