- Volume 71, Issue 8, 2021

Three novel corynebacterial species were isolated from soil sampled at a paddock in Vilsendorf, North Rhine-Westphalia, Germany. The strains were coccoid or irregular rod-shaped, catalase-positive and pale white to yellow-orange in colour. By whole genome sequencing and comparison of the 16S rRNA genes as well as the whole genome structure, it was shown that all three strains represent novel species of the family Corynebacteriaceae , order Corynebacteriales , class Actinobacteria . This project describes the isolation, identification, sequencing, and phenotypic characterization of the three novel Corynebacterium species. We propose the names Corynebacterium kalinowskii sp. nov. (DSM 110639T=LMG 31801T), Corynebacterium comes sp. nov. (DSM 110640T=LMG 31802T), and Corynebacterium occultum sp. nov. (DSM 110642T=LMG 31803T).

Two pairs of aerobic, Gram-stain-positive, rod-shaped strains (HY164T/HY044, HY168T/HY211) were isolated from bat faecal samples. Strains HY164T and HY044 were motile with a polar flagellum, and had 16S rRNA gene similarity of 95.1–98.6 % to Haloactinobacterium album YIM 93306T and Haloactinobacterium glacieicola T3246-1T; strains HY168T and HY211 were most similar to Ruania albidiflava DSM 18029T (96.6 %). Phylogenetic trees based on 16S rRNA gene and whole genome sequences revealed affiliation of strains HY164T and HY168T to the family Ruaniaceae , representing novel lineages in the genera Haloactinobacterium and Ruania , respectively, which was also supported by the results for average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH). For all isolates, the principal cellular fatty acids were anteiso-C15 : 0 and iso-C14 : 0. HY164T and HY168T had MK-8(H4) as the predominant isoprenoid quinone, diphosphatidylglycerol, phosphatidylglycerol, several unidentified phospholipids and glycolipids as common polar lipids while the latter strain additionally contained one unidentified aminophospholipid and one unidentified phosphoglycolipid. Besides sharing alanine, glutamic acid and lysine with HY164T, HY168T additionally contained 2,4-diaminobutyric acid in the cell-wall peptidoglycan. The whole-cell sugars of HY164T were ribose and rhamnose, while HY168T only included the latter. The DNA G+C contents of HY164T and HY168T were 71.0 and 69.1 mol%, respectively. Combining the polyphasic taxonomic data, HY164T (=CGMCC 4.7606T=JCM 33464T) is classified as representing a novel species of the genus Haloactinobacterium with the proposed name Haloactinobacterium kanbiaonis sp. nov., and HY168T (=CGMCC 1.16970T=JCM 33465T) is proposed to represent a novel species of the genus Ruania with the name Ruania zhangjianzhongii sp. nov.

A novel genistein-producing actinobacterial strain, designated strain CRPJ-33T, was isolated from the healthy leaves of a medicinal plant Xanthium sibiricum collected from Hunan Province, PR China. 16S rRNA gene sequence analysis indicated strain CRPJ-33T belonged to the genus Streptomyces and had 99.7, 99.0, 98.9, 98.9, 98.8 and 98.7% sequence similarities to Streptomyces zhihengii YIM T102T, Streptomyces eurocidicus NRRL B-1676T, Streptomyces xanthochromogenes NRRL B-5410T, Streptomyces michiganensis NBRC 12797T, Streptomyces mauvecolor LMG 20100T and Streptomyces lavendofoliae NBRC 12882T, respectively. Phylogenetic analysis of 16S rRNA gene sequences showed that strain CRPJ-33T was most closely related to S. zhihengii YIM T102T. However, digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) values between them were much less than the recommended threshold values. Furthermore, differential comparisons of the phenotypic characteristics were enough to distinguish strain CRPJ-33T from S. zhihengii YIM T102T. Meanwhile, the ANI and dDDH values or MLSA distances between strain CRPJ-33T and other type strains, which exhibited ≥98.7 % 16S rRNA gene sequence similarities to strain CRPJ-33T, were far away from the recommended threshold values. Based on these results, it is thought that strain CRPJ-33T should represent a novel species of the genus Streptomyces , for which the name Streptomyces genisteinicus sp. nov. is proposed. The type strain is CRPJ-33T (=MCCC 1K04965T=JCM 34526T). In addition, the phenotypic, chemotaxonomic and genotypic characteristics, as well as phylogenetic information revealed that the type strains of S. xanthochromogenes and S. michiganensis should belong to same genomic species. Consequently, it is proposed that S. michiganensis is a heterotypic synonym of S. xanthochromogenes for which an emended description is given.

Two strains of Actinobacteria, designated CRXT-Y-14T and CRXT-G-22T, were isolated from the healthy leaves and seeds, respectively, of a medicinal plant Xanthium sibiricum. Their taxonomic positions were determined using a polyphasic approach. Strain CRXT-Y-14T produced flexuous chains of smooth-surfaced spores. Strain CRXT-G-22T produced straight chains of smooth-surfaced spores. Their morphological features were consistent with the diagnostic characteristics of members of the genus Streptomyces . The results of 16S rRNA gene sequence analyses indicated two strains represented members of the genus Streptomyces . CRXT-Y-14T shared 99.3, 98.9, 98.8 % sequence similarities to Streptomyces atriruber NRRL B-24165T, Streptomyces avermitilis MA-4680T and Streptomyces davaonensis JCM 4913T, respectively. Whilst CRXT-G-22T exhibited highest similarity to Streptomyces acidiscabies ATCC 49003T (98.9 %). The results of phylogenetic analyses based on 16S rRNA gene sequences indicated that the closest phylogenetic neighbours of strains CRXT-Y-14T and CRXT-G-22T were S. atriruber NRRL B-24165T and S. acidiscabies ATCC 49003T, respectively. The phylogenomic analyses further confirmed the relative relationship between strain CRXT-G-22T and S. acidiscabies ATCC 49003T, but indicated that CRXT-Y-14T could represent a novel species of the genus Streptomyce. However, the average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between CRXT-Y-14T and strain CRXT-G-22T, between CRXT-Y-14T and S. atriruber NRRL B-24165T, and between CRXT-G-22T and S. acidiscabies ATCC 49003T were 85.4 and 23.2 %, 85.8 and 23.9 % and 89.1 and 34.1 %, respectively, far below the 95~96 and 70 % cut-off points recommended for delineating species. Furthermore, these two novel isolates were distinctly differentiated from their relatives in the genus Streptomyces with respect to phenotypic and chemotaxonomic characteristics. On the basis of these data, CRXT-Y-14T and CRXT-G-22T clearly represent two novel species within the genus Streptomyces , for which the names Streptomyces xanthii sp. nov. (type strain CRXT-Y-14T = MCCC 1K04966T= JCM 34527T) and Streptomyces roseirectus sp. nov. (type CRXT-G-22T = MCCC 1K04979T= JCM 34565T) are proposed.

A novel actinomycete, designated as strain WCH-YHL-001T, was isolated from skin biopsy specimens of a patient at West China Hospital, Chengdu, Sichuan Province, PR China. The cells were Gram-positive, aerobic, heterotrophic and non-motile. They formed an extensive substrate with short aerial mycelia, whose branches fragmented into rod-shaped elements. Growth occurred at 10–40 °C, pH 5.0–12.0 and with NaCl concentrations of 0–4.0 % (w/v). The major cellular fatty acids of strain WCH-YHL-001T were C16 : 0, C18 : 1  ω9c, C18 : 0 10-methyl and summed feature 3. The predominant respiratory quinone was MK-8 (H4ω-cycl). The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol mannoside, unknown phospholipids and unidentified glycolipids. The diagnostic diamino acid of peptidoglycan was meso-diaminopimelic acid. The whole-cell sugar pattern consisted of arabinose and glucose. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain WCH-YHL-001T belonged to the genus Nocardia . The average nucleotide identity (ANI) and in silico DNA–DNA hybridization (isDDH) values between strain WCH-YHL-001T and type strains of Nocardia species were lower than the cut-offs (≥95–96 % for ANI and ≥70 % for isDDH) required to define a bacterial species. The genomic DNA G+C content was 67.8 mol%. Phylogenetic, physiological and chemotaxonomic data suggested that strain WCH-YHL-001T represented a novel species of the genus Nocardia , for which the name Nocardia huaxiensis sp. nov. is proposed, with the type strain WCH-YHL-001T (=GDMCC 4.181T=JCM 34475 T=NBRC 114973T).

The aerobic primarily chemoorganotrophic actinobacterial strain MWH-Mo1T was isolated from a freshwater lake and is characterized by small cell lengths of less than 1 µm, small cell volumes of 0.05–0.06 µm3 (ultramicrobacterium), a small genome size of 1.75 Mbp and, at least for an actinobacterium, a low DNA G+C content of 54.6 mol%. Phylogenetic analyses based on concatenated amino acid sequences of 116 housekeeping genes suggested the type strain of Aurantimicrobium minutum affiliated with the family Microbacteriaceae as its closest described relative. Strain MWH-Mo1T shares with the type strain of that species a 16S rRNA gene sequence similarity of 99.6 % but the genomes of the two strains share an average nucleotide identity of only 79.3 %. Strain MWH-Mo1T is in many genomic, phenotypic and chemotaxonomic characteristics quite similar to the type strain of A. minutum . Previous intensive investigations revealed two unusual traits of strain MWH-Mo1T. Although the strain is not known to be phototrophic, the metabolism is adjusted to the diurnal light cycle by up- and down-regulation of genes in light and darkness. This results in faster growth in the presence of light. Additionally, a cell size-independent protection against predation by bacterivorous flagellates, most likely mediated by a proteinaceous cell surface structure, was demonstrated. For the previously intensively investigated aerobic chemoorganotrophic actinobacterial strain MWH-Mo1T (=CCUG 56426T=DSM 107758T), the establishment of the new species Aurantimicrobium photophilum sp. nov. is proposed.

A novel filamentous Actinobacterium, designated strain FXJ1.1311T, was isolated from soil collected in Ngari (Ali) Prefecture, Qinghai-Tibet Plateau, western PR China. The strain showed antimicrobial activity against Gram-positive bacteria and Fusarium oxysporum. Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that strain FXJ1.1311T belonged to the genus Lentzea and showed the highest sequence similarity to Lentzea guizhouensis DHS C013T (98.04%). Morphological and chemotaxonomic characteristics supported its assignment to the genus Lentzea . The genome-wide average nucleotide identity between strain FXJ1.1311T and L. guizhouensis DHS C013T as well as other Lentzea type strains was <82.2 %. Strain FXJ1.1311T also formed a monophyletic line distinct from the known Lentzea species in the phylogenomic tree. In addition, physiological and chemotaxonomic characteristics allowed phenotypic differentiation of the novel strain from L. guizhouensis . Based on the evidence presented here, strain FXJ1.1311T represents a novel species of the genus Lentzea , for which the name Lentzea tibetensis sp. nov. is proposed. The type strain is FXJ1.1311T (=CGMCC 4.7383T=DSM 104975T).

Two rod-shaped and Gram-stain-positive bacteria (strains C64T and C62) were isolated in 2020 from faeces of greater white-fronted geese (Anser albifrons) from Poyang Lake, PR China. Their optimal growth conditions were at 37 °C, pH 7.0 and with 0.5 % (w/v) NaCl. The two isolates showed a highest 16S rRNA gene sequence similarity to Bowdeniella nasicola DSM 19116T (92.1 %). Phylogenetic/phylogenomic analyses indicated that strains C64T and C62 clustered independently in the vicinity of the genera Varibaculum , Winkia and Mobiluncus within the family Actinomycetaceae , but could not be classified clearly as members of any of these known genera. The average amino acid identity values between our isolates and available genomes of members of the family Actinomycetaceae were around the genus threshold value (45–65 %). The major cellular fatty acids of the strains were C18 : 1ω9c and C16 : 0. The predominant polar lipids were phosphatidylinositol, phosphatidylglycerol, phosphatidylcholine, diacylglycerol, triacylglycerol and cardiolipin. The amino acid composition of peptidoglycan contained alanine, glutamic acid and glycine. The major respiratory menaquinones were MK-8(H4) and MK-9(H4). The whole cell sugars included galactose, arabinose and glucose. On the basis of the results of the 16S rRNA gene sequences comparison, whole-genome phylogenomic analysis, phenotypic and chemotaxonomic characteristics, we propose that strains C64T and C62 represent a novel species belonging to a novel genus within the family Actinomycetaceae , for which the name Nanchangia anserum gen. nov., sp. nov. is proposed. The type strain is Nanchangia anserum C64T (=CGMCC 1.18410T=GDMCC 1.1969T=KCTC 49511T=KACC 22143T).

A hyperthermophilic, strictly anaerobic archaeon, designated strain SY113T, was isolated from a deep-sea hydrothermal vent chimney on the Southwest Indian Ridge at a water depth of 2770 m. Enrichment and isolation of strain SY113T were performed at 85 °C at 0.1 MPa. Cells of strain SY113T were irregular motile cocci with peritrichous flagella and generally 0.8–2.4 µm in diameter. Growth was observed at temperatures between 50 and 90 °C (optimum at 85 °C) and under hydrostatic pressures of 0.1–60 MPa (optimum, 27 MPa). Cells of SY113T grew at pH 4.0–9.0 (optimum, pH 5.5) and a NaCl concentration of 0.5–5.5 % (w/v; optimum concentration, 3.0 % NaCl). Strain SY113T was an anaerobic chemoorganoheterotroph and grew on complex proteinaceous substrates such as yeast extract and tryptone, as well as on maltose and starch. Elemental sulphur stimulated growth, but not obligatory for its growth. The G+C content of the genomic DNA was 55.0 mol%. Phylogenetic analysis of the 16S rRNA sequence of strain SY113T showed that the novel isolate belonged to the genus Thermococcus . On the basis of physiological characteristics, average nucleotide identity values and in silico DNA–DNA hybridization results, we propose a novel species, named Thermococcus aciditolerans sp. nov. The type strain is SY113T (=MCCC 1K04190T=JCM 39083T).

A novel mesophilic and aerobic ammonia-oxidizing archaeon of the phylum Thaumarchaeota , strain NM25T, was isolated from coastal eelgrass zone sediment sampled in Shimoda (Japan). The cells were rod-shaped with an S-layer cell wall. The temperature range for growth was 20–37 °C, with an optimum at 30 °C. The pH range for growth was pH 6.1–7.7, with an optimum at pH 7.1. The salinity range for growth was 5–40 %, with an optimum range of 15–32 %. Cells obtained energy from ammonia oxidation and used bicarbonate as a carbon source. Utilization of urea was not observed for energy generation and growth. Strain NM25T required a hydrogen peroxide scavenger, such as α-ketoglutarate, pyruvate or catalase, for sustained growth on ammonia. Growth of strain NM25T was inhibited by addition of low concentrations of some organic compounds and organic mixtures, including complete inhibition by glycerol, peptone and yeast extract. Phylogenetic analysis of four concatenated housekeeping genes (16S rRNA, rpoB, rpsI and atpD) and concatenated AmoA, AmoB, AmoC amino acid sequences indicated that the isolate is similar to members of the genus Nitrosopumilus . The closest relative is Nitrosopumilus ureiphilus PS0T with sequence similarities of 99.5 % for the 16S rRNA gene and 97.2 % for the amoA gene. Genome relatedness between strain NM25T and N. ureiphilus PS0T was assessed by average nucleotide identity and digital DNA–DNA hybridization, giving results of 85.4 and 40.2 %, respectively. On the basis of phenotypic, genotypic and phylogenetic data, strain NM25T represents a novel species of the genus Nitrosopumilus , for which the name sp. nov, is proposed. The type strain is NM25T (=NBRC 111181T=ATCC TSD-147T).

A Gram-negative, non-motile, non-spore-forming, aerobic and short rod-shaped bacterial strain R32T, was isolated from seawater of the South Atlantic Ocean. Strain R32T grew at 10–40 °C (optimum 28 °C), at pH 6.0–8.0 (optimum 7.0), and in the presence of 3–8 % NaCl (w/v) (optimum 5 %). Cells were oxidase- and catalase-positive. The 16S rRNA gene sequence of strain R32T shared the highest similarities with Mesonia oceanica (98.3 %), followed by Salegentibacter salarius (93.0 %), Salegentibacter mishustinae (92.8 %), Salegentibacter salegens (92.5 %) and Mesonia maritima (92.4 %). The dominant fatty acids were iso-C15 : 0 (32.7 %) and iso-C17 : 0 3-OH (21.1 %). Menaquinone-6 (MK-6) was detected as the sole respiratory quinone. The polar lipids found were phosphatidylethanolamine, three aminolipids and three unidentified lipids. The DNA G+C content was 35.0 mol%. The ANI value and dDDH value between strain R32T and the Salegentibacter and Mesonia species were 70.5–85.8 % and 18.7–30.5 %, respectively. Based on the results of the polyphasic characterization, strain R32T is considered to represent a novel species of the genus Mesonia , for which the name Mesonia hitae sp. nov. is proposed. The type strain is R32T (=MCCC 1A09780T=KCTC 72004T).

Four marine bacterial strains were isolated from a thallus of the brown alga Ascophyllum nodosum collected in Roscoff, France. Cells were Gram-stain-negative, strictly aerobic, non-flagellated, gliding, rod-shaped and grew optimally at 25–30 °C, at pH 7–8 and with 2–4 % NaCl. Phylogenetic analyses of their 16S rRNA gene sequences showed that the bacteria were affiliated to the genus Zobellia (family Flavobacteriaceae , phylum Bacteroidetes ). The four strains exhibited 97.8–100 % 16S rRNA gene sequence similarity values among themselves, 97.9–99.1 % to the type strains of Zobellia amurskyensis KMM 3526T and Zobellia laminariae KMM 3676T, and less than 99 % to other species of the genus Zobellia . The DNA G+C content of the four strains ranged from 36.7 to 37.7 mol%. Average nucleotide identity and digital DNA–DNA hybridization calculations between the new strains and other members of the genus Zobellia resulted in values of 76.4–88.9 % and below 38.5 %, respectively. Phenotypic, phylogenetic and genomic analyses showed that the four strains are distinct from species of the genus Zobellia with validly published names. They represent two novel species of the genus Zobellia , for which the names Zobellia roscoffensis sp. nov. and Zobellia nedashkovskayae sp. nov. are proposed with Asnod1-F08T (RCC6906T=KMM 6823T=CIP 111902T) and Asnod2-B07-BT (RCC6908T=KMM 6825T=CIP 111904T), respectively, as the type strains.

A novel Gram-stain-negative strain, WQ 117T, isolated from the faeces of Rhinopithecus bieti collected at Yunnan Snub-nosed Monkey National Park, Yunnan province, PR China, was subjected to a polyphasic taxonomic study. The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate represented a member of the genus Faecalibacter , sharing 97.64 % sequence similarity with the type strain Faecalibacter macacae YIM 102668T. The G+C content of the genomic DNA of WQ117T was 30.5 mol%. The predominant isoprenoid quinone was MK-6. The major cellular fatty acids was iso-C15 : 0. The whole genome average nucleotide identity (gANI) values and the digital DNA–DNA hybridization values between WQ 117T and YIM 102668T were 79.66 % and 22.20 %, respectively. Growth occurred at 0–50 °C (optimally at 28–35 °C), pH 7.0–9.0 (optimally at pH 8.0) and with 0–2 % (w/v) NaCl (optimally without NaCl). On the basis of the taxonomic evidence, a novel species, Faecalibacter rhinopitheci sp. nov., is proposed. The type strain is WQ 117T (=KCTC 82394T=CCTCC AA 2020027T).

Two bacterial strains, designated SS33T and Y03T, were isolated from marine sediment and marine red alga collected on the coast of Weihai, PR China. Based on the results of 16S rRNA gene sequence analysis, strain SS33T was found to be closely related to Primorskyibacter marinus PX7T, Pelagivirga dicentrarchi YLY04T, Palleronia marisminoris DSM 26347T and Maribius pontilimi GH1-23T with 94.8, 94.6, 94.5 and 94.5 % sequence similarity; strain Y03T was found to be closest to Flavivirga aquimarina EC2D5T, Flavivirga eckloniae ECD14T and Flavivirga amylovorans JC2681T with 96.4, 96.1 and 96.0 % sequence similarity. Strain SS33T grew at 4–37 °C (optimum, 33 °C), at pH 6.0–9.5 (optimum, pH 7.5–8.0) and in the presence of 0–10 % (w/v) NaCl (optimum, 3.0 %). Chemotaxonomic analysis of strain SS33T showed that the predominant respiratory quinone was ubiquinone-10. The major fatty acids (>10.0 %) included C18 : 1  ω7c and C16 : 0. The major polar lipids included phosphatidylglycerol, phosphatidylcholine, one unidentified phospholipid, one unidentified glycolipid, one unidentified polar lipid and two unidentified aminolipids. Strain Y03T grew at 15–40 °C (optimum, 28 °C), at pH 6.5–8.0 (optimum, pH 7.0) and in the presence of 0.5–9.0 % (w/v) NaCl (optimum, 2.0%). Chemotaxonomic analysis showed that the predominant respiratory quinone was menaquinone-6. The major fatty acids (>10.0 %) included iso-C15 : 0, iso-C15 : 1 G, iso-C17 : 0 3-OH and iso-C15 : 0 3-OH. The major polar lipids included phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid and four unidentified polar lipids. Based on the polyphasic data, strain SS33T is considered to represent a novel species of the genus Palleronia , for which the name Palleronia sediminis sp. nov. is proposed, with the type strain SS33T (=KCTC 62986T=MCCC 1H00387T). Strain Y03T is considered to represent a novel species of the genus Flavivirga , for which the name Flavivirga algicola sp. nov. is proposed, with the type strain Y03T (=KCTC 72001T=MCCC 1H00386T).

A bacterial strain, arapr2T, was isolated from agricultural soil sampled in Reims, France. Based on its 16S rRNA gene sequence, the strain was affiliated to the family Sphingobacteriaceae and more specifically to the genus Sphingobacterium . The strain had 98.31 % 16S rRNA gene sequence similarity to its closest relative Sphingobacterium canadense CR11T and 98.25 % to Sphingobacterium pakistanensis NCCP-246T. Genome relatedness indexes revealed that the average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between arapr2T and its closest relative ( S. canadense CR11T) were 92.97 % and 52.00 %, respectively; for S. pakistanensis NCCP-246T, the ANI and dDDH values were 82.46 and 27.6%, respectively. The genomic DNA of strain arapr2T was 6.02 Mbp long, had a DNA G+C content of 40.4 mol% and had 5504 protein-coding genes. The results obtained in this study suggests that strain arapr2T (CIP 111872T=LMG 31848T) represents a new species for which the name Sphingobacterium prati sp. nov. is proposed. Due to the fact that this strain has been isolated using wheat straw as carbon source, this novel bacterial strain represents a promising biotechnological tool for the fractionation of lignocellulosic biomass in the context of biorefinery development.

A Gram-stain-negative, non-motile bacterial strain, designated SW124T, was isolated from a deep-sea sediment sample collected from the Indian Ocean. SW124T was aerobic and catalase-positive. The strain grew at 4–40 °C (optimum, 30 °C), at pH 5.0–8.6 (optimum, pH 7.0) and in the presence of 0.5–9.5 % (w/v) NaCl (optimum, 3.0%). The results of comparative analyses of the 16S rRNA gene sequence indicated that SW124T was grouped in the vicinity of the genus Rhodonellum in the family Cyclobacteriaceae . The quinone system contained menaquinone MK-7. The predominant cellular fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c). SW124T contained phosphatidylethanolamine (PE) as the major polar lipid. The genomic DNA G+C content of SW124T was 41.7 mol%. On the basis of its phenotypic characteristics and phylogenetic data, we propose that strain SW124T (=CGMCC 1.16171T=KCTC 82235T) represents a novel species of a novel genus, with the name Pararhodonellum marinum gen. nov., sp. nov.

A novel bacterial strain, designated as HN-E44T, was isolated from marine sponge collected from Yangpu Bay, Hainan, PR China. Strain HN-E44T was Gram-stain-negative, non-motile, catalase-positive, oxidase-negative, rod-shaped and yellow-pigmented. Growth occurred at 4–37 °C (optimum, 28 °C), at pH 6–8 (pH 7) and in 0.5–14 % (w/v) NaCl (3–5 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain HN-E44T formed an independent cluster with Marixanthomonas ophiurae JCM 14121T within the family Flavobacteriaceae and had the highest sequence similarity of 93.6 % to the closest type strain M. ophiurae JCM 14121T. The major fatty acids were iso-C15 : 0, anteiso-C15 : 0, iso-C17 : 0 3-OH, summed feature 3 (C16 : 1  ω7c and/or C16 : 1  ω6c) and iso-C15 : 1 G. The polar lipids comprised phosphatidylethanolamine, sphingolipid, four unidentified phospholipids, an unidentified aminophospholipid and an unidentified lipid. The respiratory quinone was identified as MK-6. The genomic DNA G+C content was determined to be 40.6 mol%. The average nucleotide identity (ANI) and average amino acid identity (AAI) values between strain HN-E44T and closest type strain M. ophiurae JCM 14121T were, respectively, 79.6 and 85.2 %, both of which were below thresholds for species delineation (95–96 % ANI and 95–96 % AAI), but were over thresholds for genus delineation (73.98 % ANI and 70–76 % AAI). The combined genotypic and phenotypic distinctiveness demonstrated that strain HN-E44T could be differentiated from closely related genera. Therefore, it is proposed that strain HN-E44T represents a novel species of the genus Marixanthomonas , for which the name Marixanthomonas spongiae sp. nov. is proposed, with the type strain HN-E44T (=MCCC 1K03332T=LMG 30459T).

Two carbon dioxide-requiring, gliding, Gram-stain-negative strains, designated p1a2T and 051621, were isolated from subgingival plaque in association with severe periodontitis. The 16S rRNA gene sequence analysis revealed that they represented members of the genus Capnocytophaga and had less than 96.4 % pairwise similarity with species with validly published names in this genus. The whole-genome sequences of those strains had less than 91.9 % average nucleotide identity and 48.4 % digital DNA–DNA hybridization values with the other type strains of species of the genus Capnocytophaga , both below the species delineation threshold. The results of pan-genomic analysis indicated that p1a2T and 051621 shared 765 core gene families with the other ten species in this genus, and the numbers of strain-specific gene families were 493 and 455, respectively. The major fatty acids were iso-C15 : 0 and C16 : 0. A combination of phenotypic, chemotaxonomic, phylogenetic and genotypic data clearly indicate that p1a2T and 051621 should be considered to represent a novel species of the genus Capnocytophaga , for which the name Capnocytophaga periodontitidis sp. nov. is proposed. The type strain is p1a2T (=CGMCC 1.17337T=JCM 34126T).