Ancylobacter moscoviensis sp. nov., novel facultatively methylotrophic bacteria from activated sludge and the reclassification of Starkeya novella (Starkey 1934) Kelly et al. 2000 as Ancylobacter novellus comb. nov., Starkeya koreensis Im et al. 2006 as Ancylobacter koreensis comb.nov., Angulomicrobium tetraedrale Vasil'eva et al. 1986 as Ancylobacter tetraedralis comb. nov., Angulomicrobium amanitiforme Fritz et al. 2004 as Ancylobacter amanitiformis comb. nov., and Methylorhabdus multivorans Doronina et al. 1996 as Ancylobacter multivorans comb. nov., and emended description of the genus Ancylobacter.

Three novel facultatively methylotrophic bacteria, strains 3CT, 1A, 8P, were isolated from activated sludges. The isolates were aerobic, Gram-stain-negative, non-motile, non-spore forming rods multiplying by binary fission. The predominant polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethylethanolamine, phosphatidylmonomethylethanolamine, and diphosphatidylglycerol. The major fatty acids of cells were С18:1ω7c, C19:0ω8c cyclo and C16:0. Levels of 16S rRNA gene similarity indicates that the closely relatives are representatives of the genera Starkeya, Ancylobacter, Angulomicrobium and Methylorhabdus (96.4-99.4%). Genomic comparisons of 3CT and its closest relatives, S. novella DSM 506T and S. koreensis Jip08T, shared 87.3 and 86.8% nucleotide identity and 28.3 and 26.8% digital DNA-DNA hybridization values, respectively. The average amino acid identities between the strain 3CT and representatives of Starkeya, Ancylobacter and Angulomicrobium were in the range of 75.6-84.3%, which combines these strains into a single genus and gives rise to their reclassification. Based on polyphasic analyses, the strains 3CT, 1A, 8P represents a novel species of the genus Ancylobacter, for which the name Ancylobacter moscoviensis sp. nov. is proposed. The type strain is 3CT (= VKM B-3218T = KCTC 62336T). Furthermore, we also suggested the reclassification of Starkeya novella as Ancylobacter novellus comb. nov., Starkeya koreensis as Ancylobacter koreensis comb. nov., Angulomicrobium tetraedrale as Ancylobacter tetraedralis comb. nov., Angulomicrobium amanitiforme as Ancylobacter amanitiformis comb. nov. and Methylorhabdus multivorans as Ancylobacter multivorans comb. nov. with the emended description of the genus Ancylobacter.

Ancylobacter radicis sp. nov., a novel aerobic methylotrophic bacteria associated with plants.

The two novel bacterial strains, designated as VTT and ML, were isolated from roots of cinquefoil (Potentilla sp.) and leaves of meadow-grass (Poa sp.) on the flooded bank of lake, respectively. These isolates were Gram-negative, non-spore-forming, non-motile, rod-shaped cells, utilized methanol, methylamine, and polycarbon compounds as carbon and energy sources. In the whole-cell fatty acid pattern of strains prevailed C18:1ω7c and C19:0cyc. Based on the phylogenetic analysis of 16S rRNA gene sequences, strains VTT and ML were closely related to the representatives of the genus Ancylobacter (98.3-98.5%). The assembled genome of strain VTT has a total length of 4.22 Mbp, and a G + C content is 67.3%. The average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA-DNA hybridization (dDDH) values between strain VTT and closely related type strains of genus Ancylobacter were 78.0-80.6%, 73.8-78.3% and 22.1-24.0%, respectively, that clearly lower than proposed thresholds for species. On the basis of the phylogenetic, phenotypic, and chemotaxonomic analysis, isolates VTT and ML represent a novel species of the genus Ancylobacter, for which the name Ancylobacter radicis sp. nov. is proposed. The type strain is VTT (= VKM B-3255T = CCUG 72400T). In addition, novel strains were able to dissolve insoluble phosphates, to produce siderophores and plant hormones (auxin biosynthesis). According to genome analysis genes involved in the biosynthesis of siderophores, polyhydroxybutyrate, exopolysaccharides and phosphorus metabolism, as well as the genes involved in the assimilation of C1-compounds (natural products of plant metabolism) were found in the genome of type strain VTT.

Hansschlegelia quercus sp. nov., a novel methylotrophic bacterium isolated from oak buds.

Novel aerobic, restricted facultatively methylotrophic bacteria were isolated from buds of English oak (Quercus robur L.; strain DubT) and northern red oak (Quercus rubra L.; strain KrD). The isolates were Gram-negative, asporogenous, motile short rods that multiplied by binary fisson. They utilized methanol, methylamine and a few polycarbon compounds as carbon and energy sources. Optimal growth occurred at 25 °C and pH 7.5. The dominant phospholipids were phosphatidylethanolamine, phosphatidylcholine, diphosphatidylglycerol and phoshatidylglycerol. The major cellular fatty acids of cells were C18 : 1 ω7c, 11-methyl C18 : 1 ω7c and C16 : 0. The major ubiquinone was Q-10. Analysis of 16S rRNA gene sequences showed that the strains were closely related to the members of the genus Hansschlegelia: Hansschlegelia zhihuaiae S113T(97.5-98.0 %), Hansschlegelia plantiphila S1T (97.4-97.6 %) and Hansschlegelia beijingensis PG04T(97.0-97.2 %). The 16S rRNA gene sequence similarity between strains DubT and KrD was 99.7 %, and the DNA-DNA hybridization (DDH) result between the strains was 85 %. The ANI and the DDH values between strain DubT and H. zhihuaiae S113T were 80.1 and 21.5  %, respectively. Genome sequencing of the strain DubT revealed a genome size of 3.57 Mbp and a G+C content of 67.0 mol%. Based on the results of the phenotypic, chemotaxonomic and genotypic analyses, it is proposed that the isolates be assigned to the genus Hansschlegelia as Hansschlegelia quercus sp. nov. with the type strain DubT (=VKM B-3284T=CCUG 73648T=JCM 33463T).

Methylopila carotae sp. nov., a facultative methylotroph, isolated from a root of Daucus carota L.

An aerobic facultatively methylotrophic bacterium, designated strain Das4.1T, was isolated from a root of Daucus carota L. The cells of this strain were observed to be Gram-stain negative, asporogenous, non-motile short rods multiplying by binary fission. Strain Das4.1T can utilise methanol, methylamine and a variety of polycarbon compounds as carbon and energy sources. C1-compounds were found to be assimilated via the isocitrate lyase-negative variant of the serine pathway. On medium with 0.5% methanol, growth of strain Das4.1T was observed at pH 5.5-9.0 (optimum, pH 6.0-7.0) and 18-37 °C (optimum, 24-29 °C) and in the presence of 0-2% (w/v) NaCl (optimum, 0.05%). Cells are catalase and oxidase positive and synthesise indole from L-tryptophan. The major fatty acids of methanol-grown cells were identified as C18:1ω7c, C18:0 and 11-methyl-C18:1ω7c. The predominant phospholipids were found to be phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylmonomethylethanolamine. The major respiratory quinone was identified as Q-10. The DNA G + C content of strain Das4.1T was determined to be 67.3 mol% (Tm). Phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that strain Das4.1T belongs to the genus Methylopila and shows high sequence similarity to Methylopila oligotropha 2395AT (98.4%) and Methylopila capsulata IM1T (98.0%). However, the DNA-DNA relatedness of strain Das4.1T with M. oligotropha 2395AT was only 22 ± 3%. Based on genotypic, chemotaxonomic and physiological characterisation, the isolate can be classified as a novel species of the genus Methylopila, for which the name Methylopila carotae sp. nov. is proposed. The type strain is Das4.1T (= VKM B-3244T = CCUG 72399T).

Methylobacillus methanolivorans sp. nov., a novel non-pigmented obligately methylotrophic bacterium.

Three strains of obligately methylotrophic Betaproteobacteria (ZT, SP and M3) with the ribulose monophosphate pathway of C1 assimilation are described. The isolates were strictly aerobic, Gram-stain-negative, asporogenous, motile (strains ZT and M3) or non-motile (strain SP) rods that multiplied by binary fisson, and were mesophilic and neutrophilic. All three strains utilized methanol but only strains SP and M3 utilized methylamine as carbon and energy sources. The prevailing cellular fatty acids were straight-chain saturated C16 : 0 and unsaturated C16 : 1ω7c acids. The major ubiquinone was Q-8. The predominant phospholipids were phosphatidylethanolamine, phosphatidylglycerol and cardiolipin. Ammonia was assimilated by glutamate dehydrogenase. The DNA G+C contents of strains ZT, SP and M3 were 51.0, 52.0 and 52.0 mol% (Tm), respectively. Levels of 16S rRNA gene sequence similarity between the three strains were very high (99.9-100 %), and they shared high levels of DNA-DNA relatedness (88-98 %). Based on 16S rRNA gene sequence analysis and DNA-DNA relatedness (19-30 %) with the type strains of the genus Methylobacillus, the novel isolates ZT, SP and M3 are classified as representing a novel species of this genus, for which the name Methylobacillus methanolivorans sp. nov. is proposed. The type strain is ZT (=VKM B-3037T=JCM 31401T=CCUG 68999T).

Ancylobacter sonchi sp. nov., a novel methylotrophic bacterium frоm roots of Sonchus arvensis L.

An aerobic facultatively methylotrophic bacterium was isolated from roots of Sonchus arvensis L. and designated strain OsotT The cells of this strain were Gram-stain-negative, asporogenous, motile short rods multiplying by binary fisson. They utilized methanol, methylamines and a variety of polycarbon compounds as the carbon and energy sources. Methanol was assimilated after sequential oxidation to formaldehyde and CO2 via the ribulose bisphosphate pathway. The organism grew optimally at 22-29 °C and pH 7.5-8.0. The dominant phospholipids were phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol and diphosphatidylglycerol (cardiolipin). The major cellular fatty acids of strain OsotT cells grown in R2A medium were C18 : 1ω7c (49.0 %), C19 : 0ω8c cyclo (38.3 %) and C16 : 0 (8.4 %). The major ubiquinone was Q-10. The DNA G+C content of strain OsotT was 66.1 mol% (Tm). On the basis of 16S rRNA gene sequence analysis strain OsotT is phylogenetically related to the members of genus Ancylobacter (97.1-98.8 % sequence similarity). Based on 16S rRNA gene sequence analysis and DNA-DNA relatedness (27-29 %) with type strains of the genus Ancylobacter, the novel isolate is classified as a new species of this genus and named Ancylobacter sonchi sp. nov.; the type strain is OsotT (=VKM B-3145T=JCM 32039T).

Methyloversatilis thermotolerans sp. nov., a novel thermotolerant facultative methylotroph isolated from a hot spring.

A newly isolated facultatively methylotrophic bacterium (strain 3t(T)) was investigated. Cells of the isolate were Gram-stain-negative, asporogenous, non-motile rods that multiplied by binary fission. The strain utilized methanol, methylamine and a variety of multicarbon compounds as carbon and energy sources. Growth occurred at pH 6.5-8.5 (optimally at 7.0-7.5) and at 10-45 °C (optimally at 30-37 °C). The major fatty acids of methanol-grown cells were C16 : 1ω7c and C16 : 0. The predominant phospholipids were phosphatidylethanolamine and phosphatidylglycerol. The major ubiquinone was Q-8. Strain 3t(T) possessed pyrroloquinoline quinone (PQQ)-linked methanol dehydrogenase and assimilated C1 units at the level of formaldehyde and CO2 via the serine cycle. The DNA G+C content of the strain was 63.6 mol% (Tm). On the basis of 16S rRNA gene sequence similarity (98.1 %) and rather low DNA-DNA relatedness (30 %) with the type strain of the type species of the genus Methyloversatilis (Methyloversatilis universalis FAM5(T)), and physiological and biochemical characteristics, the isolate was classified as a representative of a new species of the genus and named Methyloversatilis thermotolerans 3t(T) ( = VKM B-2692(T) = CCUG 61694(T) = DSM 25156(T)).

Methylopila musalis sp. nov., an aerobic, facultatively methylotrophic bacterium isolated from banana fruit.

A newly isolated, facultatively methylotrophic bacterium (strain MUSA(T)) was investigated. The isolate was strictly aerobic, Gram-stain-negative, asporogenous, motile, rod-shaped and multiplied by binary fission. The strain utilized methanol, methylamine and an apparently narrow range of multi-carbon compounds, but not methane, dichloromethane or CO2/H2, as the carbon and energy sources. Growth occurred at pH 5.5-9.5 (optimum, pH 7.0) and 16-40 °C (optimum, 28-30 °C). The major fatty acids of methanol-grown cells were C18 : 1ω7c, C18 : 0 and 11-methyl-C18 : 1ω7c . The predominant phospholipids were phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol and phosphatidylmonomethylethanolamine. The major ubiquinone was Q-10. The strain had methanol and methylamine dehydrogenases as well as the enzymes of the N-methylglutamate pathway (lyases of γ-glutamylmethylamide and N-methylglutamate). C1 assimilation occurs via the isocitrate lyase-negative serine pathway. Ammonium was assimilated by glutamate dehydrogenase and the glutamate cycle (glutamate synthase/glutamine synthetase). The DNA G+C content of the strain was 64.5 mol% (determined from the melting temperature). Based on 16S rRNA gene sequence similarity (97.0-98.9 %) and DNA-DNA relatedness (36-38 %) with representatives of the genus Methylopila (Methylopila capsulata IM1(T) and Methylopila jiangsuensis JZL-4(T)) the isolate was classified as a novel species of the genus Methylopila, for which the name Methylopila musalis sp. nov. is proposed. The type strain is MUSA(T) ( = VKM B-2646(T) = DSM 24986(T) = CCUG 61696(T)).

Telmatobacter bradus gen. nov., sp. nov., a cellulolytic facultative anaerobe from subdivision 1 of the Acidobacteria, and emended description of Acidobacterium capsulatum Kishimoto et al. 1991.

A gram-negative, facultatively anaerobic, chemo-organotrophic, non-pigmented, slow-growing bacterium was isolated from acidic Sphagnum peat and designated strain TPB6017(T). Cells of this strain were long rods that multiplied by normal cell division and were motile by means of a single flagellum. Cells grew under reduced oxygen tension and under anoxic conditions and were able to ferment sugars and several polysaccharides, including amorphous and crystalline cellulose. Strain TPB6017(T) was a psychrotolerant acidophile capable of growth between pH 3.0 and 7.5 (optimum 4.5-5.0) and at 4-35 °C (optimum 20-28 °C). It was extremely sensitive to salt stress; growth was inhibited at NaCl concentrations above 0.1 % (w/v). The major fatty acids were iso-C(15 : 0) and iso-C(17 : 1)ω9c; the polar lipids were phosphatidylethanolamine and a number of phospholipids and aminophospholipids with an unknown structure. The quinone was MK-8. The DNA G+C content was 57.6 mol%. Comparative 16S rRNA gene sequence analysis revealed that strain TPB6017(T) was a member of subdivision 1 of the phylum Acidobacteria and belonged to a phylogenetic lineage defined by the acidophilic aerobic chemo-organotroph Acidobacterium capsulatum (92.3 % sequence similarity). However, cell morphology, type of flagellation, the absence of pigment, differences in fatty acid and polar lipid composition, possession of a cellulolytic capability, inability to grow under fully oxic conditions and good growth in anoxic conditions distinguished strain TPB6017(T) from A. capsulatum. Therefore, it is proposed that strain TPB6017(T) represents a novel acidobacterium species in a new genus, Telmatobacter bradus gen. nov., sp. nov.; strain TPB6017(T) ( = DSM 23630(T) = VKM B-2570(T)) is the type strain.

Methylophilus flavus sp. nov. and Methylophilus luteus sp. nov., aerobic, methylotrophic bacteria associated with plants.

Novel yellow, obligately methylotrophic and restricted facultatively methylotrophic bacteria, respectively designated strains Ship(T) and Mim(T), with the ribulose monophosphate pathway of C(1) assimilation are described. Cells were strictly aerobic, Gram-negative, asporogenous, non-motile rods that multiply by binary fission, were mesophilic and neutrophilic and synthesized indole-3-acetic acid and exopolysaccharide. The predominant cellular fatty acids were C(16 : 0) and C(16 : 1). The major ubiquinone was Q-8. The predominant phospholipids were phosphatidylethanolamine and phosphatidylglycerol; diphosphatidylglycerol was absent. The two strains lacked α-ketoglutarate dehydrogenase and glutamate dehydrogenase. They assimilated ammonium via the glutamate cycle enzymes glutamine synthetase and glutamate synthase. The DNA G+C contents of strains Ship(T) and Mim(T) were 50.7 and 54.5 mol% (T(m)), respectively. The level of 16S rRNA gene sequence similarity between these strains was very high (99.8 %) but they shared a low level of DNA-DNA relatedness (44 %). Based on 16S rRNA gene sequence analysis and low levels of DNA-DNA relatedness with the type strains of recognized species of the genus Methylophilus (31-36 %), strains Ship(T) and Mim(T) are considered to represent novel species of the genus Methylophilus, for which the names Methylophilus flavus sp. nov. (type strain Ship(T) =DSM 23073(T) =VKM B-2547(T) =CCUG 58411(T)) and Methylophilus luteus sp. nov. (type strain Mim(T) =DSM 22949(T) =VKM B-2548(T) =CCUG 58412(T)) are proposed.

Methyloligella halotolerans gen. nov., sp. nov. and Methyloligella solikamskensis sp. nov., two non-pigmented halotolerant obligately methylotrophic bacteria isolated from the Ural saline environments.

Two newly isolated halotolerant obligately methylotrophic bacteria (strains C2(T) and SK12(T)) with the serine pathway of C1 assimilation are described. The isolates are strictly aerobic, Gram negative, asporogenous, non-motile rods, forming rosettes, multiplying by binary fission. Mesophilic and neutrophilic, accumulate intracellularly compatible solute ectoine and poly-ß-hydroxybutyrate. The novel strains are able to grow at 0 up to 16% NaCl (w/v), optimally at 3-5% NaCl. The major cellular fatty acids are C18:1ω7c and C19:0cyc and the prevailing quinone is Q-10. The predominant phospholipids are phosphatidylcholine, phosphatidylglycerol, phosphatidyldimethylethanolamine and phosphatidylethanolamine. Assimilate NH4(+) by glutamate dehydrogenase and via the glutamate cycle (glutamine synthetase and glutamate synthase). The DNA G+C contents of strains C2(T) and SK12(T) are 60.9 and 60.5 mol% (Tm), respectively. 16S rRNA gene sequence similarity between the two new isolates are 99% but below 94% with other members of the Alphaproteobacteria thus indicating that they can be assigned to a novel genus Methyloligella. Rather low level of DNA-DNA relatedness (53%) between the strains C2(T) and SK12(T) indicates that they represent two separate species of the new genus, for which the names Methyloligella halotolerans gen. nov., sp. nov. and Methyloligella solikamskensis sp. nov. are proposed. The type strain of Methyloligella halotolerans is C2(T) (=VKM B-2706(T)=CCUG 61687(T)=DSM 25045(T)) and the type strain of Methyloligella solikamskensis is SK12(T) (=VKM B-2707(T)=CCUG 61697(T)=DSM 25212(T)).

Methylobacillus arboreus sp. nov., and Methylobacillus gramineus sp. nov., novel non-pigmented obligately methylotrophic bacteria associated with plants.

Two newly isolated obligate methanol-utilizing bacteria (strains Iva(T) and Lap(T)) with the ribulose monophosphate pathway of C(1) assimilation are described. The isolates are strictly aerobic, Gram negative, asporogenous, motile rods multiplying by binary fission, mesophilic and neutrophilic, synthesize indole-3-acetate. The prevailing cellular fatty acids are straight-chain saturated C(16:0) and unsaturated C(16:1) acids. The major ubiquinone is Q-8. The predominant phospholipids are phosphatidylethanolamine, phosphatidylglycerol and cardiolipin. Ammonia is assimilated by glutamate dehydrogenase. The DNA G+C contents of strains Iva(T) and Lap(T) are 54.0 and 50.5mol% (T(m)), respectively. Based on 16S rRNA gene sequence analysis and DNA-DNA relatedness (38-45%) with type strains of the genus Methylobacillus, the novel isolates are classified as the new species of this genus and named Methylobacillus arboreus Iva(T) (VKM B-2590(T), CCUG 59684(T), DSM 23628(T)) and Methylobacillus gramineus Lap(T) (VKM B-2591(T), CCUG 59687(T), DSM 23629(T)). The GenBank accession numbers for the 16S rRNA gene and mxaF gene sequences of the strains Iva(T) and Lap(T) are GU937479, GU937478 and HM030736, HM030735, respectively.

Chelativorans multitrophicus gen. nov., sp. nov. and Chelativorans oligotrophicus sp. nov., aerobic EDTA-degrading bacteria.

Two previously isolated strains (DSM 9103(T) and LPM-4(T)) able to grow with EDTA (facultatively and obligately, respectively) as the source of carbon, nitrogen and energy were investigated in order to clarify their taxonomic positions. The strains were strictly aerobic, Gram-negative, asporogenous and non-motile rods that required biotin for growth. Reproduction occurred by binary fission. The strains were mesophilic and neutrophilic. Their major fatty acids were summed feature 7 (consisting of C(18 : 1)omega7c, C(18 : 1)omega9t and/or C(18 : 1)omega12t) and C(19 : 0) cyclo omega8c. The polyamine pattern revealed homospermidine as a major polyamine. Predominant polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, phosphatidyldimethylethanolamine, phosphatidylmonomethylethanolamine and diphosphatidylglycerol. Mesorhizobium-specific ornithine lipid was absent. The predominant isoprenoid quinone was Q-10. The DNA G+C values were 60.8 and 63.1 mol% (T(m)) for strains LPM-4(T) and DSM 9103(T), respectively. The level of 16S rRNA gene sequence similarity between these EDTA-utilizers was 99.3 % while the DNA-DNA hybridization value was only 37 %. Both strains were phylogenetically related to members of the genera Aminobacter and Mesorhizobium (95-97 % sequence similarity). However, DNA-DNA hybridization values between the novel EDTA-degrading strains and Aminobacter aminovorans DSM 7048(T) and Mesorhizobium loti DSM 2626(T) were low (10-11 %). Based on their genomic and phenotypic properties, the new alphaproteobacterial strains are assigned to a novel genus, Chelativorans gen. nov., with the names Chelativorans multitrophicus sp. nov. (type strain DSM 9103(T)=VKM B-2394(T)) and Chelativorans oligotrophicus sp. nov. (type strain LPM-4(T)=VKM B-2395(T)=DSM 19276(T)).

Acidisoma tundrae gen. nov., sp. nov. and Acidisoma sibiricum sp. nov., two acidophilic, psychrotolerant members of the Alphaproteobacteria from acidic northern wetlands.

Three obligately aerobic, heterotrophic bacteria, designated strains WM1T, TPB606T and TPB621, were isolated from acidic Sphagnum-dominated tundra and Siberian wetlands in Russia. Cells of these isolates were Gram-negative, non-motile coccobacilli that occurred singly, in pairs or in chains, and were covered by large capsules. The novel strains were moderately acidophilic and psychrotolerant organisms capable of growth at pH 3.0-7.6 and 2-30 degrees C. Cells contained numerous intracellular poly-beta-hydroxybutyrate granules (3-4 per cell). The major cellular fatty acid was cyclo C19:0omega8c and the predominant quinone was Q-10. Strains TPB606T and TPB621, isolated from Siberian wetland, possessed almost identical 16S rRNA gene sequences and shared 97.2% sequence similarity with tundra strain WM1T. The three strains were shown to belong to the Alphaproteobacteria, but were related only distantly to the type strains of acidophilic bacteria Acidisphaera rubrifaciens (93.4-94.3% 16S rRNA gene sequence similarity), Rhodopila globiformis (92.2-93.3%), and members of the genera Acidiphilium (91.3-93%) and Acidocella (91.8-92.4%). The DNA G+C contents of the novel strains were 60.5-61.9 mol%. The low levels of DNA-DNA relatedness (37%) and a number of phenotypic differences between the Siberian strains TPB606T and TPB621 and the tundra strain WM1T indicated that they represent two separate species. As the three isolates are clearly distinct from all recognized acidophilic members of the Alphaproteobacteria, they are considered to represent two novel species of a new genus, for which the names Acidisoma tundrae gen. nov., sp. nov. and Acidisoma sibiricum sp. nov. are proposed. The type strain of Acidisoma sibiricum is TPB606T (=DSM 21000T=VKM B-2487T) and the type strain of Acidisoma tundrae is WM1T (=DSM 19999T=VKM B-2488T).