- Volume 72, Issue 4, 2022

A bacterial strain, designated S9-5T, was isolated from moraine samples collected from the north slope of Mount Everest at an altitude of 5 500 m above sea level. A polyphasic study confirmed the affiliation of the strain with the genus Sphingomonas . Strain S9-5T was an aerobic, Gram-stain-negative, non-spore-forming, non-motile and rod-shaped bacterium that could grow at 10–40 °C, pH 5–8 and with 0–9 % (w/v) NaCl. Q-10 was its predominant respiratory menaquinone. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, an unidentified aminophospholipid and eight unidentified lipids comprised the polar lipids of strain S9-5T. Its major fatty acids were summed feature 8 (C18 : 1  ω7c and/or C18 : 1  ω6c) and C16 : 0. The G+C content was 65.75mol%. Phylogenetic analysis based on 16S rRNA sequences showed that strain S9-5T was phylogenetically closely related to Sphingomonas panaciterrae DCY91T (98.17 %), Sphingomonas olei K-1-16T (98.11 %) and Sphingomonas mucosissima DSM 17494T (97.39 %). The average nucleotide identity values among strain S9-5T and Sphingomonas panaciterrae DCY91T, Sphingomonas olei K-1-16T and Sphingomonas mucosissima DSM 17494T were 78.82, 78.87 and 78.29 %, respectively. Based on the morphological, physiological and chemotaxonomic data, strain S9-5T (=JCM 34750T=GDMCC 1.2714T) should represent a novel species of the genus Sphingomonas , for which we propose the name Sphingomonas radiodurans sp. nov.

A novel species of Campylobacter was isolated from bile samples of chickens with spotty liver disease in Australia, making it the second novel species isolated from chickens with the disease, after Campylobacter hepaticus was isolated and described in 2016. Six independently derived isolates were obtained. They were Gram-stain-negative, microaerobic, catalase-positive, oxidase-positive and urease-negative. Unlike most other species of the genus Campylobacter , more than half of the tested strains of this novel species hydrolysed hippurate and most of them could not reduce nitrate. Distinct from C. hepaticus , many of the isolates were sensitive to 2,3,5-triphenyltetrazolium chloride (0.04%) and metronidazole (4 mg ml−1), and all strains were sensitive to nalidixic acid. Phylogenetic analysis using 16S rRNA and hsp60 gene sequences demonstrated that the strains formed a robust clade that was clearly distinct from recognized Campylobacter species. Whole genome sequence analysis of the strains showed that the average nucleotide identity and the genome blast distance phylogeny values compared to other Campylobacter species were less than 86 and 66%, respectively, which are below the cut-off values generally recognized for isolates of the same species. The genome of the novel species has a DNA G+C content of 30.6 mol%, while that of C. hepaticus is 27.9 mol%. Electron microscopy showed that the cells were spiral-shaped, with bipolar unsheathed flagella. The protein spectra generated from matrix-assisted laser desorption/ionization time of flight analysis demonstrated that they are different from the most closely related Campylobacter species. These data indicate that the isolates belong to a novel Campylobacter species, for which the name Campylobacter bilis sp. nov. is proposed. The type strain is VicNov18T (=ATCC TSD-231T=NCTC 14611T).

A novel phosphate-solubilizing and 3-indoleacetic acid producing bacterium, designated strain CMYE1T, was isolated from the phyllosphere of pomelo (Citrus maxima) in Meizhou, Guangdong Province, PR China. Cells were Gram-stain-negative, facultative aerobic, non-spore-forming, rod-shaped and motile with peritrichous flagella. It had the highest 16S rRNA gene sequence similarity to   Kalamiella piersonii   NRRL B-65522T (99.0 %), followed by   Pantoea cypripedii   LMG 2657T (98.1 %),   Erwinia iniecta   B120T (97.7 %),   Mixta intestinalis   29Y89BT (97.6 %) and other species (<97.6 %). However, phylogenomic analyses clearly showed that strain CMYE1T should be assigned into the genus   Erwinia  , and was most closely related to   Erwinia oleae   LMG 25322T (96.7 %). Genome comparisons showed that the novel strain shared ≤83.2 % average nucleotide identity and ≤26.5 % digital DNA–DNA hybridization values with closely related strains, respectively. It contained C16 : 0, C17 : 0 cyclo, summed feature 3 (C16 : 1  ω7c and/or C16 : 1  ω6c) and summed feature 8 (C18 : 1  ω7c and/or C18 : 1  ω6c) as the major fatty acids. Based on the results of phylogenetic, phenotypic and chemotaxonomic analyses, as well as genome comparisons, strain CMYE1T belongs to a novel species of the genus   Erwinia  , for which the name Erwinia phyllosphaerae sp. nov. is proposed with the type strain CMYE1T (=GDMCC 1.2674T=JCM 34792T).

Two Gram-staining-negative, aerobic, rod-shaped bacteria NNCM1T and NNCM2T were isolated from the scleractinian coral Acropora digitifera. NNCM1T grew with 0.5–12 % (w/v) NaCl (optimum, 3–6 %), at 18–37 °C (optimum, 28 °C) and at pH 6.0–10.0 (optimum, 7.0–8.0). NNCM2T grew with 0.5–10 % (w/v) NaCl (optimum, 2 %), at 18–37 °C (optimum, 28 °C) and at pH 6.5–9.0 (optimum, 7.0). The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that NNCM1T formed a lineage within the genus Algiphilus of the family Algiphilaceae, and it was distinct from the most closely related species Algiphilus aromaticivorans DG1253T, with a 16S rRNA gene sequences similarity of 97.05 %. NNCM2T formed a lineage within the family Rhodobacteraceae, and it was distinct from the closely related genera Limibaculum halophilum CAU 1123T, Paroceanicella profunda D4M1T and Pseudoruegeria aestuarii MME-001T with 93.41, 92.78 and 91.09% identities, respectively. The major respiratory quinone was Q-8 and Q-10 for NNCM1T and NNCM2T, respectively. The predominant fatty acids (more than 10 %) were summed feature 8 (39.4 %) and C16 : 0 (19.4 %) for NNCM1T and summed feature 8 (62.8 %) and C16 : 0 (12.4 %) for NNCM2T. The DNA G+C contents of NNCM1T and NNCM2T were 63.3 and 63.4 mol% respectively. The polar lipids of NNCM1T comprised one diphosphatidylglycerol, one phosphatidylethanolamine, one phosphatidylglycerol and one unknown polar lipid, while those of NNCM2T comprised one phosphatidylethanolamine, one phosphatidylglycerol, one aminolipid and four unknown polar lipids. Phenotypic characteristics (physiological, biochemical and chemotaxonomic) also supported the taxonomic novelty of the two isolates. Thus, NNCM1T is considered to represent a novel species within genus Algiphilus , for which the name Algiphilus acroporae sp. nov. is proposed. The type strain is NNCM1T (=KCTC 82966T=MCCC 1K06445T). NNCM2T represents a novel genus and species within the family Rhodobacteraceae, for which the name Coraliihabitans acroporae gen. nov. sp. nov. is proposed. The type strain is NNCM2T (=KCTC 82967T=MCCC 1K06408T).

A novel pale white-pigmented bacterial strain designated YC-7-48T was isolated from activated sludge in China. Cells of the strain, which grew at 15–37 °C (optimum at 30 °C) and pH 6.0–9.0 (optimum at 7.0), were Gram-stain-negative, rod-shaped and motile. Strain YC-7-48T had 97.4–97.1% 16S rRNA gene sequence similarity to type strains of eight species in the genera Pusillimonas , Eoetvoesia , Paralcaligenes , Parapusillimonas and Paracandidimonas of the family Alcaligenaceae . Phylogenetic analysis based on 16S rRNA gene sequencing placed the strain on a separate branch in the genus Pusillimonas and showed that it exhibited 97.4, 97.3 and 96.6% similarity to Pusillimonas caeni EBR-8-1T, Pusillimonas noertemannii BN9T and Pusillimonas maritima 17-4AT, respectively. The genome size of strain YC-7-48T was 3202438 bp, with 54.3 mol% G+C content. According to the genome analysis, YC-7-48T encodes several heavy metal resistance proteins and enzymes related to the metabolism of nicotine and aromatic compounds. The results of digital DNA–DNA hybridization and average nucleotide identity analyses based on whole genome sequences between strain YC-7-48T and the closely related strains indicated that the strain represented a new species of the genus Pusillimonas . The chemotaxonomic results identified Q-8 as the predominant respiratory quinone, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, diphosphatidylglycerol and two unidentified aminolipids as the major polar lipids, and C16:0 (27.4 %), C17:0 cyclo (22.0 %), C18:0 (11.7 %) and C19:0 cyclo ω8c (9.5 %) as the major fatty acids. Thus, based on morphological, chemotaxonomic and phylogenetic characterization and genomic data, we proposed that the isolate is a representative of a novel species named Pusillimonas minor sp. nov., with the type strain YC-7-48T (=CGMCC 1.17466T=KACC 21349T).

A novel bacterial strain, designated MK52T, was isolated from the phycosphere of Microcystis aeruginosa . Strain MK52T is a Gram-stain-negative, pink-pigmented, rod-shaped, strictly aerobic bacterium. In 16S rRNA phylogenetic analysis, the MK52T strain was most closely related to Rhizorhabdus wittichii RW1T (98.66 %) and Rhizorhabdus histidinilytica UM2T (98.51 %). The genomic DNA G+C content of strain MK52T was calculated to be 65.5 mol%. The average nucleotide identity values of strain MK52T with R. wittichii RW1T and R. histidinilytica UM2T were 80.35 and 80.23 %, respectively, with digital DNA–DNA hybridization values of 23.6 and 22.9 %, respectively, and average amino acid identities of 75.59 and 75.79 %, respectively. The major isoprenoid quinone was Q-10, and the predominant polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and sphingoglycolipid. Fatty acid methyl ether analysis showed that summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) was the main cellular fatty acid in strain MK52T. Strain MK52T cells grew at 21–34 °C (optimum, 30 °C), pH 5–8 (optimum, pH 7) and with 0–2 % (w/v) NaCl (optimum, 0.5 % NaCl). Rhizorhabdus phycosphaerae sp. nov. is proposed as a new species (=KCTC 72877T=DSM 111424T) based on its genotypic and phenotypic characteristics.

A Gram-stain-negative, rod-shaped, motile and aerobic marine bacterium, designated strain NBU2595T, was isolated from marine sediment sampled on Meishan Island, located in the East China Sea. Strain NBU2595T grew at 10–40 °C (optimum, 37 °C), at NaCl concentration of 0–10.0 % (w/v; optimum, 0.5 %) and at pH 6.0–8.0 (optimum, pH 7.0). Catalase and oxidase activities and H2S production were positive. Methyl red reaction and hydrolysis of casein, starch and Tweens 20, 40, 60 and 80 were negative. The major cellular fatty acids were summed feature 8 (C18 : 1  ω7c and/or C18 : 1  ω6c), C18 : 1 2-OH and C18 : 0 3-OH. The sole respiratory quinone was ubiquinone 10. The major polar lipids were phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine and phosphatidylmonomethylethanolamine. Comparative analysis of 16S rRNA gene sequences showed highest similarity to Pelagibius litoralis CL-UU02T (97.9%), and low similarities (<92.9 %) to other species. Phylogenetic analyses indicated that strain NBU2595T clustered with the genus Pelagibius and was closely related to P. litoralis CL-UU02T. The average nucleotide identity and digital DNA–DNA hybridization values between strain NBU2595T and the related species of the genus Pelagibius were well below the thresholds for prokaryotic species delineation. The DNA G+C content was 66.5 mol%. Based on its phenotypic, chemotaxonomic and genotypic data, strain NBU2595T should be placed in the genus Pelagibius as representing a novel species, for which the name Pelagibius marinus sp. nov. is proposed. The type strain is NBU2595T (=MCCC 1K04773T=KCTC 82223T).

A rod-shaped, Gram-stain-negative, aerobic and non-motile bacterium, designated strain Y4T, was isolated from an aquaculture farm in Xiamen, PR China. Strain Y4T had 94.8, 93.3 and 91.8 % 16S rRNA gene sequence similarity to Paremcibacter congregatus ZYLT, Emcibacter nanhaiensis HTCJW17T and Luteithermobacter gelatinilyticus MEBiC09520T, respectively. The genomic DNA G+C content of strain Y4T was 42.7 mol%. The average amino acid identity and percentage of conserved proteins values between strain Y4T and type strains of the family Emcibacteraceae were 57.9–58.6 % and 44.5–47.6 %, respectively. Optimal growth was observed at 28 °C, at pH 7.0 and with 2 % (w/v) NaCl. The novel strain Y4T required Ca2+, K+ and Mg2+ ions in addition to NaCl for growth. The dominant fatty acids of strain Y4T were summed feature 3 (C16 : 1  ω7c/C16 : 1  ω6c), summed feature 8 (C18 : 1  ω7c/C18 : 1  ω6c) and C14 : 0 2-OH. The polar lipid profile contained phosphatidylethanolamine, phosphatidyglycerol, three unidentified aminolipids, four unidentified aminophospholipids and two unidentified lipids. Cells contained exclusively ubiquinone Q-10. On the basis of the polyphasic analysis, strain Y4T (=MCCC 1K06278T=KCTC 82926T) is considered to represent a novel species in a novel genus of the family Emcibacteraceae , for which the name Pseudemcibacter aquimaris gen. nov., sp. nov. is proposed.

Two enterobacterial strains, designated YMB-R21T and YMB-R22, were isolated from larvae of mealworm Tenebrio molitor L. and examined for their taxonomic characteristics. A 16S rRNA gene-based neighbour-joining tree showed that the two isolates formed two distinct sublineages within the family Enterobacteriaceae and were separated from other genera of the family. The isolates showed 16S rRNA gene sequence similarity of 98.9 % to each other and ≤96.5 % to members of the order Enterobacteriales . The phylogenomic analysis based on 92 singly-copy core genes showed that the two isolates belonged to the family Enterobacteriaceae and formed a distinct sublineage at a position located remotely from the genera of the family. The loosely associated members were the type strain of Erwinia teleogrylli and members of the genus Shimwellia . Average nucleotide identity and digital DNA–DNA hybridization values showed that the isolates represented members of a novel species in the family Enterobacteriaceae . The values of amino acid identity between the two isolates and the closest relatives were 74.5–75.0 % with the type strain of E. teleogrylli and 74.5–74.8 % with the type strains of two Shimwellia species, while E. teleogrylli showed the amino acid identity values of 76.3–76.5 % with two Shimwellia species. Based on the results obtained here, we propose a new genus Tenebrionicola with the description of Tenebrionicola larvae sp. nov. (type strain YMB-R21T=KCTC 82597T=CCM 9152T and strain YMB-R22=KCTC 82598=CCM 9153), with the transfer of Erwinia teleogrylli Liu et al. 2016 to a new genus Entomohabitans as Entomohabitans teleogrylli comb. nov. (type strain SCU-B244T=CGMCC 1.12772T=DSM 28222T=KCTC 42022T).

Strain NGK35T is a motile, Gram-stain-negative, rod-shaped (1.0–2.1 µm long and 0.6–0.8 µm wide), aerobic bacterium that was isolated from plastic-polluted landfill soil. The strain grew at temperatures between 6 and 37 °C (optimum, 28 °C), in 0–10 % NaCl (optimum, 1 %) and at pH 6.0–9.5 (optimum, pH 7.5–8.5). It was positive for cytochrome c oxidase, catalase as well as H2S production, and hydrolysed casein and urea. It used a variety of different carbon sources including citrate, lactate and pyruvate. The predominant membrane fatty acids were C16 : 1 cis9 and C16 : 0, followed by C17 : 0 cyclo and C18 : 1 cis11. The major polar lipids were phosphatidylglycerol and phosphatidylethanolamine, followed by diphosphatidyglycerol. The only quinone was ubiquinone Q-8. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NGK35T belongs to the genus Paenalcaligenes (family Alcaligenaceae ), appearing most closely related to Paenalcaligenes hominis CCUG 53761AT (96.90 %) and Paenalcaligenes suwonensis ABC02-12T (96.94 %). The genomic DNA G+C content of strain NGK35T was 52.1 mol %. Genome-based calculations (genome-to-genome distance, average nucleotide identity and DNA G+C content) clearly indicated that the isolate represents a novel species within the genus Paenalcaligenes . Based on phenotypic and molecular characterization, strain NGK35T can clearly be differentiated from its phylogenetic neighbours establishing a novel species, for which the name Paenalcaligenes niemegkensis sp. nov. is proposed. The type strain is NGK35T (=DSM 113270T=NCCB 100854T).

Two Gram-stain-negative, motile with single polar flagellum, rod-shaped bacterial strains, named SJ-9T and SJ-92T, were isolated from saline soils from Inner Mongolia, PR China. SJ-9T and SJ-92T grew at pH 6.5–10.0 and 7.0–11.0, 10–35 °C, and in the presence of 0–5 % and 0–8 % NaCl, respectively. Both strains were positive for oxidase, and negative for catalase. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that SJ-9T clustered with Luteimonas marina FR1330T (sharing 97.9 % 16S rRNA gene similarity), Luteimonas huabeiensis HB2T (96.5 %), ‘Luteimonas wenzhouensis’ YD-1 (96.6 %), and Luteimonas composti CC-YY255T (95.1 %), and shared low 16S rRNA gene similarities (<97.0 %) with all the other type strains; while SJ-92T clustered with Luteimonas aestuarii B9T (98.2 %), and shared low 16S rRNA gene similarities (<98.0 %) with all the other type strains. The two strains shared 97.4 % 16S rRNA gene similarity with each other. The major cellular fatty acids of both strains are iso-C15 : 0 and summed feature 9 (C16 : 0 10-methyl and/or iso-C17 : 1ω9c). The major polar lipids of both strains are diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The only respiratory quinone for both strains is ubiquinone-8 (Q-8). The genomic DNA G+C contents are 69.3 and 70.4 mol%, respectively. The digital DNA–DNA hybridization (dDDH) and average nucleotide identity by blast (ANIb) values between the two strains were 22.6 and 77.5 %, while the values between SJ-9T and ‘L. wenzhouensis’ YD-1, L. marina FR1330T, and L. huabeiensis HB2T were 38.1, 39.2, and 21.9 %, and 82.5, 84.4, and 78.5 %, while those between SJ-92T and L. aestuarii B9T were 21.3 and 76.7 %. On the basis of the phenotypic, physiological and phylogenetic results, SJ-9T and SJ-92T represent two novel species of the genus Luteimonas , for which the names Luteimonas saliphila [type stain SJ-9T (=CGMCC 1.17377T=KCTC 82248T)] and Luteimonas salinisoli [type strain SJ-92T (=CGMCC 1.17695T=KCTC 82208T)] are proposed.

A neutrophilic iron-oxidizing bacterium, strain MIZ01T, which was previously isolated from a wetland in Ibaraki, Japan, was taxonomically characterized in detail. Strain MIZ01T was a motile, curved-rod shaped, Gram-stain-negative bacterium. It was able to grow at 10–40 °C (optimally at 30–35 °C) and at pH 5.5–7.0 (optimally at pH 6.0). It grew microaerobically and chemolithoautotrophically using thiosulfate, in addition to ferrous iron, as the sole electron donor. Major cellular fatty acids of strain MIZ01T were C16 : 1  ω7c/C16 : 1  ω6c and C16 : 0. The complete genome sequence (2.74 Mbp) was determined, showing that its DNA G+C content was 60.0 mol%. Phylogenetic analyses indicated that strain MIZ01T belonged to the family Gallionellaceae , class Betaproteobacteria , and was closely related to an isolate tentatively named ‘Sideroxydans lithotrophicus’ ES-1 (98.2 % of 16S rRNA gene sequence similarity). Based on its phenotypic and phylogenetic characteristics, we conclude that strain MIZ01T represents a new genus and species in the family Gallionellaceae for which we propose the name Sideroxyarcus emersonii gen. nov., sp. nov. The type strain is strain MIZ01T (=JCM 39089T=DSM 111897T).

We investigated a taxonomically novel group of the genus Acinetobacter , which included five strains isolated from soil and water samples collected in preserved forest areas in Czechia between 2013 and 2021. The whole-genome sequences of the strains were 3.1–3.2 Mb in size, with G+C contents of 38.0–38.2 mol%. Core genome-based phylogenetic analysis showed that they formed a compact and deeply branched clade within the genus. The genomic average nucleotide identity based on blast/digital DNA–DNA hybridization values for the novel strains were 99.2–99.6 %/95.2–98.4 %, whereas those between the novel strains and the type strains of the known Acinetobacter species reached <78 %/<24 %. The results of the genus-wide analysis of whole-cell MALDI-TOF mass spectra supported the sharp distinctness of the group. The five strains were non-glucose acidifying, nonhaemolytic, nonproteolytic and growing at 28 °C, but not at 32 °C; they assimilated acetate, benzoate, ethanol, l-histidine, 4-hydroxybenzoate, dl-lactate and malonate but not 4-aminobutyrate, l-aspartate or 2,3-butanediol; this phenotype is unique among the known Acinetobacter species. We conclude that the five strains represent a novel environmental species, for which the name Acinetobacter silvestris sp. nov. is proposed, with the type strain ANC 4999T (=CCM 9207T=CCUG 75877T=CNCTC 8124T).