- Volume 75, Issue 6, 2025

The actinobacterial family Microbacteriaceae comprises a diverse group of Gram-positive bacteria with high G+C content and complex taxonomic challenges. Traditional polyphasic approaches, based on 16S rRNA phylogeny and phenotypic traits, have in some instances resulted in polyphyletic taxonomic groupings, necessitating genome-wide methodologies to better resolve evolutionary relationships. This study employs a taxogenomic approach – incorporating 16S rRNA gene sequencing, core protein phylogeny, average amino acid identity and percentage of conserved proteins – to reassess the genera Leifsonia, Salinibacterium, Homoserinimonas, Glaciibacter, Antiquaquibacter and Diaminobutyricibacter. The findings reveal significant polyphyly in Leifsonia, Glaciibacter and Salinibacterium, indicating ecological convergence rather than shared ancestry. Proposed taxonomic revisions include the reclassification of Salinibacterium soli and Salinibacterium metalliresistens into Antiquaquibacter, Salinibacterium hongtaonis and Salinibacterium sedimenticola into Homoserinimonas, and Leifsonia psychrotolerans and Leifsonia kafniensis into Glaciibacter. Diaminobutyricibacter tongyongensis should be incorporated into Leifsonia. Additionally, Leifsonia rubra is reassigned to Salinibacterium. Two new genera were also proposed to encompass “Leifsonia flava” and Glaciibacter flavus, named Orlajensenia gen. nov. and another to encompass Leifsonia bigeumensis, named Leifsonella gen. nov. These genome-based insights provide a refined framework for the taxonomy of Microbacteriaceae, enhancing our understanding of their evolutionary and ecological roles.

The root nodules of Alnus glutinosa remain a relatively understudied niche, with poorly described associated microbial communities. In this study, the isolate RTGN1T was recovered from root nodules collected from Gateshead, UK, and was identified as belonging to Amycolatopsis based on 16S rRNA gene similarity and phylogenomic placement. This isolate was polyphasically characterized, displaying the ability to grow between 12 and 28 °C and pH 6 and 8 and exhibiting the genes necessary to produce the polar lipids phosphatidylethanolamine and phosphatidylglycerophosphate, alongside DL-type peptidoglycan, which are diagnostic of Amycolatopsis. Overall genomic relatedness index values were below the cut-off value for delineating a novel species. As such, it is proposed that RTGN1T be recognized as the type strain (=CECT 30870T=CABI 507287T) of Amycolatopsis ponsaeliensis sp. nov. The RTGN1T isolate was screened using in silico and in vitro methods and was found to possess a number of genes and pathways related to secondary metabolite production and plant growth promotion. Such genes may serve as an avenue of future study regarding biotechnological potential and use as a bioinoculant to increase phytoremediation efficiency.

Two marine actinomycete-like strains, MCC20T and MCC57, were isolated from Chanthaburi (Thailand) mangrove sediment. Their taxonomic classifications were established through a polyphasic approach. Despite differences in colony morphotypes, genetic and chemotaxonomic analyses confirmed them as the same species within the genus Streptomyces. Both strains contained ll-diaminopimelic acid in their cell wall, with glucose, mannose, ribose and rhamnose identified as whole-cell sugars. Their phospholipid profile comprises phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannoside. The predominant fatty acids were iso-C15:0, anteiso-C15:0, iso-C16:0 and anteiso-C17:0 with MK-9(H8) as the primary menaquinone, while MK-9(H6) and MK-9(H4) were unique to strain MCC57. Both strains exhibited anticancer activity against colorectal (HCT116) and lung (A549) cancer cells, with strain MCC20T being more potent. Their 16S rRNA gene sequences showed 100% similarity, with 99.2% similarity to Streptomyces fumigatiscleroticus NBRC 12999T. Nevertheless, a phylogenomic tree placed them closer to Streptomyces spinosirectus CRSS-Y-16T, Streptomyces plumbidurans KC 17012T and Streptomyces spinosisporus 7R016T. Nearly 100% average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values highlighted the identity of strains MCC20T and MCC57, while ANI (89.4%) and dDDH (35.5%) values were well below the respective 95 and 70% thresholds for related species. This supported their novelty. Based on their genotypes and phenotypes, strains MCC20T (=NBRC 117131T=TBRC 19240T) and MCC57 (=NBRC 117132=TBRC 19241) are identified as phenotypic variants of a new species, Streptomyces sediminimaris sp. nov., with strain MCC20T designated as the type strain (~9.2 Mb genome, 72.0 mol% G+C content).

Four Gram-stain-positive, facultative anaerobic, yellow-pigmented and short rod-shaped strains, designated zg-Y625T, zg-Y843, zg-Y1090T and zg-Y1211, were isolated from the intestinal contents of Marmota himalayana in Qinghai Province, PR China. Strains zg-Y625T and zg-Y1090T showed the highest 16S rRNA gene sequence similarities of 99.7% and 99.9% to Microbacterium pullorum DSM 112390T, respectively, followed by 99.2% and 99.5% to Microbacterium oleivorans JCM 14341T and 99.1% and 99.0% to Microbacterium paulum LMG 32277T. Phylogenetic analyses based on 16S rRNA gene sequences and phylogenomic analyses using whole-genome sequences revealed that these four strains belong to the genus Microbacterium, forming two separate clades distinct from all other known Microbacterium species. The genome sizes of strains zg-Y625T and zg-Y1090T were 3.26 and 3.07 Mb, respectively, with DNA G+C contents of 70.5 and 70.9 mol%. The average nucleotide identity and digital DNA–DNA hybridization values between each of the novel strains and the available members of the genus Microbacterium were all below the species thresholds. Both type strains contained diphosphatidylglycerol and phosphatidylglycerol as predominant polar lipids with one unidentified glycolipid for zg-Y625T and two unidentified glycolipids for zg-Y1090T. The predominant respiratory quinone in zg-Y625T was MK-13, whilst in zg-Y1090T, both MK-11 and MK-13 were identified as the major quinones. The major fatty acids (>10%) in strains zg-Y625T and zg-Y843 were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0, whereas for zg-Y1090T and zg-Y1211, the predominant fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0. Based on phenotypic, phylogenetic, genomic and chemotaxonomic data, two novel species in the genus Microbacterium are proposed, namely, Microbacterium jiangjiandongii sp. nov. (zg-Y625T=GDMCC 1.3931T=JCM 36203T) and Microbacterium wangruii sp. nov. (zg-Y1090T=GDMCC 1.3930T=JCM 36205T).

A novel actinobacterium, designated strain 12N6T, was isolated from tropical peat swamp forest soil in Rayong Province, Thailand. The taxonomic position was determined using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 12N6T was classified within the genus Planosporangium and showed the highest percentage similarity to Planosporangium flavigriseum YIM 46034T (98.7%), followed by Planosporangium thailandense HSS8-18T (98.0%) and Planosporangium mesophilum YIM 48875T (97.9%). Strain 12N6T produced a single globose spore with a spiny surface on short sporophores of the substrate mycelia. The approximate genome size and DNA G+C content of strain 12N6T were 7.47 Mbp and 71.6 mol%, respectively. The highest average nucleotide identity and digital DNA–DNA hybridization values of genome sequences of 12N6T compared with closest species type strains (83.0% and 27.8%, respectively) are well below the thresholds for species delineation. The whole-cell hydrolysates of strain 12N6T contained meso-diaminopimelic acid, glucose, mannose, arabinose, xylose and ribose. The polar lipid profile comprised diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The major cellular fatty acids were anteiso-C17 : 0, iso-C16 : 0 and iso-C15 : 0. The analysis of phylogenetic, genomic, phenotypic and chemotaxonomic characteristics revealed that strain 12N6T is considered to represent a novel species of the genus Planosporangium, for which the name Planosporangium spinosum sp. nov. is proposed. The type strain is 12N6T (=TBRC 19149T=NBRC 117121T).

Three novel, Gram-stain-negative, non-motile, rod-shaped bacterial strains, designated Du54ᵀ, Du274ᵀ and P351ᵀ, were isolated from contaminated environments in Anseong, South Korea. Strains Du54ᵀ and Du274ᵀ originated from landfill soil, whilst P351ᵀ was obtained from parking lot soil. These sites are frequently exposed to pollutants such as petroleum hydrocarbons, heavy metals and industrial runoff, which exert selective pressures on microbial communities. The taxonomic positions of the strains were determined using a polyphasic approach, including 16S rRNA gene sequencing, draft genome analysis and whole-genome-based phylogenetic reconstruction. Phylogenetic trees based on both 16S rRNA genes and core genome sequences (Type Genome Server and AutoMLST) showed that the three isolates belong to the genus Pedobacter. Du54ᵀ exhibited the highest 16S rRNA gene sequence similarity to Pedobacter insulae KCTC 12820ᵀ (98.40%), Du274ᵀ to Pedobacter bambusae KACC 17544ᵀ (98.31%) and P351ᵀ to Pedobacter mongoliensis KCTC 52859ᵀ (97.65%). The draft genomes of Du54ᵀ, Du274ᵀ and P351ᵀ were 4.43, 4.51 and 4.63 Mb in size, with G+C contents of 37.7, 40.6 and 39.2 %, respectively. Average nucleotide identity and digital DNA–DNA hybridization values between the novel strains and their closest relatives ranged from 73.76 to 76.36% and 18.8 to 22.6%, respectively, supporting their delineation as novel species. Genomic annotation revealed 294, 302 and 238 genes in Du54ᵀ, Du274ᵀ and P351ᵀ, respectively, associated with metal resistance, efflux transporters and stress response. All strains lacked flexirubin-type pigments, contained menaquinone-7 as the major respiratory quinone and possessed phosphatidylethanolamine as the dominant polar lipid. The predominant fatty acids included iso-C16:0 and summed feature 3 (C16:1  ω7c and/or C16 : 1  ω6c). Based on these results, the names Pedobacter anseongensis sp. nov., Pedobacter immunditicola sp. nov. and Pedobacter superstes sp. nov. are proposed for strains Du54ᵀ (=KACC 23093ᵀ=LMG 32954ᵀ), Du274ᵀ (=KACC 23094ᵀ=LMG 32955ᵀ) and P351ᵀ (=KACC 23095ᵀ=LMG 32956ᵀ), respectively.

In the deep subsurface Miocene groundwater of Horonobe, Hokkaido, Japan, we isolated strain Z1-71ᵀ, an obligately anaerobic, Gram-stain-negative, non-motile bacterium with rod-shaped morphology (2.7–4.8 µm × 0.4 µm). This strain could grow at 10–42 °C (optimum, 30–35 °C), over a pH range of 6.0–9.0 (optimum, pH 7.0–7.2) and in the presence of 0–30 g l−1 NaCl (optimum, 5–15 g l−1). Physiologically, strain Z1-71ᵀ displayed positive catalase activity but negative oxidase reaction, with notable hydrogen production during d-glucose metabolism. Chemotaxonomic analysis revealed MK-7 as the sole respiratory quinone, while cellular lipid profiling identified four unidentified polar lipids, one unidentified phospholipid, one unidentified aminolipid and one unidentified glycolipid. The predominant fatty acids comprised C17:0 (23.4%), C17:1  ω6c (13.8%), anteiso-C15 :0 (6.9%) and iso-C17:0 3-OH (6.6%). Genomic characterization determined a genome size of 5.7 Mb with a G+C content of 45.9 mol%. Comprehensive phylogenetic analysis of 16S rRNA gene sequences positioned strain Z1-71ᵀ within the family Prolixibacteraceae, showing the highest sequence similarity to Gaoshiqia sediminis A06T (95.0%), followed by Mangrovibacterium diazotrophicum SCSIO N0430T (94.6%), Mangrovibacterium lignilyticum BM_7T (94.3%) and Mangrovibacterium marinum FA423T (93.6%). Digital DNA–DNA hybridization and orthologous average nucleotide identity tool using USEARCH (OrthoANIu) analyses between strain Z1-71ᵀ and G. sediminis A06T yielded values of 20.7% and 75.8%, respectively, confirming genomic distinction. Based on these phylogenetic and phenotypic characteristics, we propose strain Z1-71ᵀ (=DSM 117644ᵀ=JCM 36072ᵀ) as the type strain of a novel species, Gaoshiqia hydrogeniformans sp. nov. This discovery not only expands our understanding of microbial diversity in deep terrestrial subsurface environments but also highlights the ecological significance of hydrogen-producing anaerobes in these previously underexplored habitats.

A polyphasic taxonomic study was carried out on the bacterial EZn1T, isolated from heavy-metal-contaminated soil in the Chapala Basin, Mexico. This Gram-negative, aerobic, rod-shaped bacterium formed orange-pigmented colonies, producing the pigment flexirubin. Analysis of the 16S rRNA gene sequence revealed that EZn1T represents a member of the genus Chryseobacterium in the family Weeksellaceae and is closely related to Chryseobacterium cucumeris GSE06T (98.3%), Chryseobacterium phosphatilyticum ISE14T (97.7%) and Chryseobacterium indologenes NBCR 14944T (97.5%). The average nucleotide identity between the genomes of strain EZn1T and C. cucumeris GSE06T was 90.9%, and digital DNA–DNA hybridization showed values of less than 70% with the type strains for the related species. The polar lipids present in the strain included phosphatidylethanolamine, phosphatidylglycerol, glycolipids and unidentified aminoglycolipids, whereas the major cellular fatty acids included iso-C15 : 0 and iso-C17 : 0 3-OH. The whole genome of EZn1T was 5,003,090 bp in length, with a DNA G+C content of 36.7 mol %. The strain EZn1T showed physiological characteristics different from those of closely related Chryseobacterium species. This strain showed resistance to copper (20 mM), and its genome contained genes that may confer resistance to this metal and other heavy metals (As, Cd, Co, Cr, Hg, K, Mg, Mo, Na and Zn). According to the polyphasic analysis, the strain EZn1T (=TSD-322T=CAIM 1954T) is a novel species that we named Chryseobacterium cupriresistens sp. nov.

Two Gram-stain-negative, aerobic, non-motile, non-gliding, rod-shaped bacterial strains, designated as TBRC 19031T and TBRC 19032, were isolated from water samples collected from the Mekong River, Thailand. Strain TBRC 19031T was obtained from Chiang Saen in the upstream section near the borders with China and Myanmar, while TBRC 19032 originated from Khong Chiam, in the downstream section where the river exits Thailand. Colonies of both strains were circular, smooth and deep yellow on Reasoner’s 2A agar and did not produce flexirubin-type pigments. Phylogenetic analysis with 16S rRNA gene sequences placed both strains within the genus Flavobacterium, showing the highest sequence similarity to Flavobacterium cheonhonense ARSA-15T (98.29% for TBRC 19031T and 98.22% for TBRC 19032). However, whole-genome comparisons between the strains and F. cheonhonense ARSA-15T revealed average nt identity (89.39% and 89.29%), average aa identity (92.84% and 92.95%) and digital DNA–DNA hybridization (35.00% and 34.70%). The predominant fatty acids were iso-C15:1, iso-C15:0 and iso-C15:0 3-OH, and menaquinone MK-6 was the major respiratory quinone. The major polar lipids of both strains included phosphatidylethanolamine, steryl ester and diacylglycerol. The genome sizes were 3.02 and 3.04 Mbp, with G+C contents of 38.3% and 38.2% for TBRC 19031T and TBRC 19032, respectively. Comparative genomic analyses revealed the absence of genes involved in sulphate reduction and denitrification pathways and the presence of a gene encoding phosphatidylinositol synthase, distinguishing them from other Flavobacterium within the clade. Ecological profiling using public metagenomic datasets showed that both strains were associated with lotic freshwater environments. This study not only introduces Flavobacterium mekongense sp. nov. as a new species but also provides broader insights into the ecology, metabolism and environmental distribution of freshwater Flavobacterium. The genomic features identified here offer promising leads for future studies in microbial ecology, comparative genomics and functional gene mining in aquatic ecosystems. The type strain is TBRC 19031T (TBRC 19031T=NBRC 117006T).

A novel bacterium, designated 1RM2T, was isolated from Xinjiang Province, north-west PR China. This strain could grow under conditions of 20–45 °C, pH 5.0–10.0 and 0–10% (w/v) NaCl. The species with the highest similarity of 16S rRNA gene sequences to strain 1RM2T were strain Chryseobacterium bernardetii NCTC 13530T (97.1%) and Chryseobacterium daecheongense DSM 15235T (96.9%). The draft genome sequence G+C content of strain 1RM2T was 39.5 mol%. The average nucleotide identity and DNA–DNA hybridization values between strain 1RM2T and the two closest neighbours were 78.6%, 77.6% and 21.8%, 21.2%, respectively. The main fatty acids of strain 1RM2T were iso-C15:0, iso-C17:0 3-OH, summed feature 3 (C16:1  ω6c and/or C16:1  ω7c) and summed feature 9 (C16:0 10-methyl and/or iso-C17:1  ω9c). The main isoprenoid quinone was menaquinone-6 and polar lipids were phosphatidylethanolamine, unidentified amino phospholipids and unidentified lipids. Based on phenotypic characteristics and genotype analysis, strain 1RM2T is a new species of the genus Chryseobacterium and is proposed to be named Chryseobacterium gossypii sp. nov. (=GDMCC 1.4437T=KCTC 102275T).

Six Gram-staining-negative, aerobic, non-motile and rod-shaped bacterial strains, designated as D3-2-R+10T, C2-6-M1T, E1-3-M2, D2-2-M3, D2-2-M2 and D2-2-M1, were isolated from the shore soil of LungmuCo Lake in Xizang Autonomous Region, China. The 16S rRNA gene sequence comparisons confirmed that the six isolates belonged to the genus Algoriphagus of the family Cyclobacteriaceae. The 16S rRNA gene sequence of strains D3-2-R+10T, D2-2-M3, D2-2-M2 and D2-2-M1 exhibited the highest similarities to the type strains of Algoriphagus antarcticus LMG 21980T(98.1–98.5 %) and Algoriphagus resistens NH1T (97.9–98.4 %). Meanwhile, the 16S rRNA gene sequence of strains C2-6-M1T and E1-3-M2 showed the highest similarities to A. antarcticus LMG 21980T (98.2–98.7%). The average nt identity and digital DNA–DNA hybridization values among strains D3-2-R+10T and C2-6-M1T and their most closely related species A. antarcticus LMG 21980T were all lower than the threshold values for delineating species, indicating that they represent two separate novel species of Algoriphagus. The predominant cellular fatty acids of strains D3-2-R+10T and C2-6-M1T included iso-C15 : 0, summed feature 3 (C16 : 1  ω7c/C16 : 1  ω6c) and summed feature 9 (iso-C17 : 1  ω9c/C16 : 0 10-methyl), and the predominant respiratory quinone was MK-7. The major polar lipids of strain D3-2-R+10T comprised phosphatidylethanolamine, one unidentified phospholipid and five unidentified lipids, while those of strain C2-6-M1T included phosphatidylethanolamine, two unidentified phospholipids and seven unidentified lipids. The genome size of strains D3-2-R+10T and C2-6-M1T was 6.0 and 5.0 Mb, respectively, with the DNA G+C contents of 40.1 and 40.9 mol %. Based on the above descriptions, the six strains were identified as two novel species of the genus Algoriphagus, for which the names Algoriphagus aurantiacus sp. nov. and Algoriphagus persicinus sp. nov. were proposed, with the type strains, respectively.

The genus Lactococcus was proposed by Schleifer et al. by separating Lactococcus lactis from the genus Streptococcus. Although the family Streptococcaceae consists of four genera, each genus contains a relatively small number of species, with the exception of the genus Streptococcus, which contains more than 100 species. The genera Lactococcus and Lactovum currently comprise 26 species and a single species, respectively. This study evaluated the taxonomy of the genus Lactococcus based on the 16S rRNA gene phylogeny, core-genome phylogeny and (conserved) pairwise average amino acid identity. These evaluations clearly indicated that the genus Lactococcus could be divided into two genus-level clusters, and we propose to reclassify this genus into two; the authentic Lactococcus, which includes the L. lactis group, and a novel genus for which the name Pseudolactococcus is proposed. Three lactic acid bacterial strains, RyT2T, OfM1T and OfM2, were isolated from the gut of termites in Okinawa, Japan. Based on the combination of genetic and phenotypic data, we conclude that these isolates represent two novel species of the genera Pseudolactococcus and Lactovum, respectively, for which we propose the names Pseudolactococcus yaeyamensis sp. nov. (RyT2T=JCM 36015T=DSM 118067T) and Lactovum odontotermitis sp. nov. (OfM1T=JCM 34431T=DSM 118066T, OfM2=JCM 34432), respectively.

A corrigendum of this article has been published full details can be found at 10.1099/ijsem.0.006838

The genus Faecalibacterium is one of the major butyrate-producing bacteria in the human gut. Due to its production of beneficial metabolites and reduced populations in diseased patients, it is regarded as a potential biomarker of healthy gut microbiota. Strains Collection Nationale de Cultures de Microorganismes (CNCM) I-4540 and CNCM I-4541 were isolated from faeces of a healthy elderly and a healthy adult respectively. In this study, we conducted a taxonomic analysis of these strains. Phylogenetic analyses based on 16S rRNA gene and rpoA gene sequences revealed that the two strains belong to the genus Faecalibacterium. A core gene phylogenetic tree further supported their phylogenetic placement. CNCM I-4540 shared an average nucleotide identity (ANI) value of 96.7% and a digital DNA–DNA hybridization (dDDH) value of 74.3% with Faecalibacterium taiwanense HLW78T, indicating that CNCM I-4540 should be classified as F. taiwanense. In contrast, CNCM I-4541 did not exhibit ANI or dDDH values above the species threshold for any known species within the genus Faecalibacterium. These findings indicate that CNCM I-4541 represents a novel species within the genus Faecalibacterium, for which the name Faecalibacterium langellae sp. nov. is proposed. The type strain is CNCM I-4541T (=CIP 112513T=JCM 39552T).

Two novel bacteria (designated N501-2T and N40-8-2T) belonging to the genera Lacticaseibacillus and Levilactobacillus were isolated from traditional Chinese pickle (‘Suan cai’) and identified. Strain N501-2T was phylogenetically related to the type strains of Lacticaseibacillus baoqingensis, Lacticaseibacillus porcinae, Lacticaseibacillus manihotivorans and Lacticaseibacillus jixiensis, having 98.7–99.4% 16S rRNA gene sequence similarities. Strain N40-8-2T was phylogenetically related to the type strains of Levilactobacillus fuyuanensis, Levilactobacillus parabrevis, Levilactobacillus tujiorum, Levilactobacillus hammesii, Levilactobacillus senmaizukei and Levilactobacillus tangyuanensis, having 98.4–99.4% 16S rRNA gene sequence similarities. Strain N501-2T had 74.0–84.2% ANI (average nucleotide identity), 20.8–28.4% dDDH (digital DNA–DNA hybridization) and 73.5–86.8% AAI (average amino acid identity) values with L. manihotivorans DSM 13343T, L. porcinae JCM 19617T, L. jixiensis N163-3-2T and L. baoqingensis 47-3T. Analyses based on whole-genome sequences indicated that strain N40-8-2T was most closely related to the type strains of L. fuyuanensis, L. parabrevis, L. tujiorum and L. hammesii, having less than 87.4% ANI, 33.6% dDDH and 93.2% AAI values. Based upon the data obtained in the present study, two novel species, Lacticaseibacillus salsurae sp. nov. and Levilactobacillus muriae sp. nov., are proposed, and the type strains are N501-2T (=CCTCC AB 2024124T=JCM 37150T=LMG 33663T) and N40-8-2T (=CCTCC AB 2024128T=JCM 37001T=LMG 33659T), respectively.

A short, rod-shaped, Gram-positive, catalase-negative and facultative anaerobic bacterium, designated strain P0083T, was isolated from kimchi, a traditional Korean fermented vegetable. Phylogenetic analysis based on the nearly complete 16S rRNA and recA gene sequences placed the isolate within a distinct group from other closely related species within the Dellaglioa genus. Under anaerobic conditions on de Man, Rogosa and Sharpe agar, the bacterium formed beige, circular colonies of moderate size. Growth occurred between 4 and 25 °C, with optimal growth at 20 °C and limited growth at 30 °C. The bacterium grew at pH 5–8 and tolerated 3% NaCl. The main cellular fatty acids included C16 : 0 fatty acid methyl esters (FAME) and C18 : 1 CIS 9 FAME. Digital DNA–DNA hybridization confirmed that strain P0083T represents a novel genomic species, with Dellaglioa species sharing less than 84.22% DNA homology with strain P0083T. The genomic, phenotypic and biochemical characteristics of Dellaglioa kimchii support the hypothesis that strain P0083T (=JCM 37383T=KCTC 25916T) represents a novel species, Dellaglioa kimchii sp. nov., with P0083T as the type strain.

Two novel Gram-stain-negative, rod-shaped, facultatively anaerobic and non-motile bacterial strains, designated as S1116L3T and S4756T, were isolated from the marine sediment of Jingzi Port, Weihai, China. Strain S1116L3T grew at temperatures 15–37 ℃ within pH 5.5–9.0 and in the presence of 1.0%–10.0% (w/v) NaCl. Optimal growth required 3.0% (w/v) NaCl at 30 ℃ and pH 7.0. Strain S4756T grew at 15–37 ℃, pH 6.0–9.0 and in the presence of 1.0%–10.0% (w/v) NaCl. Optimal growth appeared with 2.0% (w/v) NaCl at 30 ℃ and pH 7.0. Strains S1116L3T and S4756T had a major fatty acid of C18 : 1 ω7ϲ. The predominant respiratory quinone of the two strains was Q10. The major polar lipids detected in the two strains were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The phylogenetic analysis based on 16S rRNA gene sequences placed the strains S1116L3T and S4756T into the genus Roseovarius. The comparison of 16S rRNA gene sequence similarities revealed that strains S1116L3T and S4756T had the closest relative with Roseovarius aquimarinus KCTC 32014T (98.4% and 97.9%, respectively). These values were below the species delineation threshold of 98.6%. The average nucleotide identity (ANI) values based on the genome similarity between strain S1116L3T and species of the genus Roseovarius ranged from 74.6% to 82.8%, while the ANI values ranged from 74.3% to 82.5% for strain S4756T, which is significantly lower than the species delineation threshold of 95%. The DNA G+C content of both strains is 63.0%. Based upon the results presented in this study, strains S1116L3T and S4756T represent two novel species of the genus Roseovarius, for which the names Roseovarius roseus sp. nov. and Roseovarius maritimus sp. nov. are proposed with the type strains S1116L3T (=KCTC 8178T=MCCC 1H01426T=SDUM 031094T) and S4756T (=KCTC 8179T=MCCC 1H01425T=SDUM 031096T), respectively.

Three Gram-stain-negative, rod-shaped, motile bacterial strains, each with a single polar flagellum, designated LB3P38T, LT1P18T and ZB1P45T, were isolated from glacier samples on the Tibetan Plateau, P.R. China. These strains grew at temperatures ranging from −2 to 32 °C (optimum 25–30 °C) and at pH values of 5.0–11.0 (optimum pH 7.0). The similarities of 16S rRNA gene sequences among these strains ranged from 99.67% to 99.93%. Phylogenetic analysis based on 16S rRNA gene sequences confirmed their affiliation with the genus Pseudomonas. Phylogenomic analysis positioned these strains in close relation to Pseudomonas svalbardensis PMCC 200367T and Pseudomonas frederiksbergensis LMG 19851T. Average nucleotide identity values and digital DNA–DNA hybridization values between these strains and other type strains of the genus Pseudomonas were below 94.6% and 63.4%, respectively. The predominant fatty acids identified in these strains were C16:0, C17:0 cyclo and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c). Based on the combined phenotypic and phylogenetic evidence, each strain is proposed to represent a novel species within the genus Pseudomonas, with the names Pseudomonas lyxosi sp. nov. (type strain=LB3 P38T=CGMCC 1.11284T=JCM 37126T), Pseudomonas arabinosi sp. nov. (type strain=LT1 P18T=CGMCC 1.11310T=JCM 37131T) and Pseudomonas frigoris sp. nov. (type strain=ZB1 P45T=CGMCC 1.23235T=JCM 37141T) proposed.