An integrated procedure for the extraction of bacterial isoprenoid quinones and polar lipids

Taxonomic description of Micromonospora reichwaldensis sp. nov. and its biosynthetic and plant growth-promoting potential

Micromonospora strains proved to be a model organism for drug discovery and plant growth promotion (PGP). Strain DSM 115977 T was subjected to polyphasic taxonomic analysis and genome mining for biosynthetic gene clusters and PGP-associated genes in order to determine its taxonomic rank and assess its biosynthetic potential. The strain was found to form a novel species within the evolutionary radiation of the genus Micromonospora. The strain contained glucose, mannose, xylose, and ribose as whole-cell sugars and the isomer DL-diaminopimelic acid in its peptidoglycan. Strain DSM 115977T had iso-C15:0, iso-C16:0, C17:1cis 9, C17:0, iso-C17:0, and 10-methyl-C17:0 as fatty acid profile (>5%) and MK10-H4 and MK10-H6 as the predominant menaquinones (>10%). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, glycophosphatidylinositol, glycophospholipids, phosphoaminolipid, unidentified lipids, and phospholipids. The genome of the strain had a size of 7.0 Mbp with a DNA G + C content of 73.4%. It formed a well-supported sub-clade with its close phylogenomic neighbor, Micromonospora echinofusca DSM 43913T (98.7%). Digital DNA-DNA hybridization and average nucleotide identity derived from sequence comparisons between the strain and its close phylogenomic neighbors were below the thresholds of 70 and 95-96% for prokaryotic species demarcation, respectively. Based on these findings, strain DSM 115977T (Asg4T = KCTC 59188T) merits to be considered as the type strain of a new species for which the name Micromonospora reichwaldensis sp. nov. is proposed. Genome mining for biosynthetic gene clusters encoding specialized secondary metabolites highlighted its ability to produce potentially novel therapeutic compounds. The strain is rich in plant growth-promoting genes whose predicted products directly and indirectly affect the development and immune system of the plant.

IMPORTANCE

In view of the significant pharmaceutical, biotechnological, and ecological potentials of micromonosporae, it is particularly interesting to enhance the genetic diversity of this genus by focusing on the isolation of novel strain from underexplored habitats, with the promise that novel bacteria will lead to new chemical entities. In this report, modern polyphasic taxonomic study confirmed the assignment of strain DSM 115977T to a novel species for which the name Micromonospora reichwaldensis sp. nov. is proposed. The strain harbors in its genomic sequence several biosynthetic gene clusters for secondary metabolites and genes associated with plant growth-promoting features. The results of this study provide a very useful basis for launching more in-depth research into agriculture and/or drug discovery.

Niallia tiangongensis sp. nov., isolated from the China Space Station

Understanding the characteristics of microbes during long-term space missions is essential for safeguarding the health of astronauts and maintaining the functionality of spacecraft. In this study, a Gram-positive, aerobic, spore-forming, rod-shaped strain JL1B1071T was isolated from the surface of hardware on the China Space Station. This strain belongs to the genus Niallia, with its closest relative being Niallia circulans ATCC 4513T. The genome of JL1B1071T is 5 166 230 bp in size, with a G+C content of 35.6 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between JL1B1071T and N. circulans ATCC 4513T are 83.3 and 27.5%, respectively, both below the recommended thresholds for species delineation. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0. The major quinone was menaquinone-7 (MK-7). Notably, strain JL1B1071T demonstrates a unique ability to hydrolyse gelatin, suggesting that it can utilize gelatin as a substrate in nutrient-limited environments. Genomic analysis of JL1B1071T revealed two conserved signature indels in the GAF domain-containing protein and DNA ligase D protein, which are specific to the genus Niallia. Additionally, structural and functional differences in proteins BshB1 and SplA were identified, which may enhance biofilm formation, oxidative stress response and radiation damage repair, thereby aiding its survival in the space environment. Based on phenotypic, physiological and chemotaxonomic characteristics, as well as genome annotation, strain JL1B1071T was considered a novel species within the genus Niallia and is proposed to be named Niallia tiangongensis sp. nov. The type strain is JL1B1071T (=GDMCC 1.4642=KCTC 43715).

Description and genomic characterization of Mesorhizobium marinum sp. nov., a bacterium isolated from sea sediment

Two Gram-stain-negative, aerobic strains, designed ZMM04-4T and ZMM04-5, were isolated from sea sediment collected from Qinzhou Bay, Guangxi Zhuang Automous Region, China. The predominant respiratory quinone was ubiquinone-10. The polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, aminophospholipid and phospholipid. The predominant fatty acids were C18:1ω7c, C19:0 cyclo ω8c and C16:0. Strain ZMM04-4T shared 99.7 % similarity of 16S rRNA gene sequence with ZMM04-5. The digital DNA-DNA hybridization and average nucleotide identity values between strain ZMM04-4T and ZMM04-5 were 92.9 % and 98.6 %, respectively, indicating that strains ZMM04-4T, ZMM04-5 belong to the same species. Phylogenetic and phylogenomic analysis indicated that strains ZMM04-4T and ZMM04-5 belong to the genus Mesorhizobium and showed the highest sequence similarity to Mesorhizobium qingshengii CGMCC 1.12097T (97.7 %-97.8 % sequence similarity) and Mesorhizobium shangrilense DSM 21850T (97.7 %-97.8 %). The average nucleotide identity and digital DNA-DNA hybridization values between strains ZMM04-4T, ZMM04-5 and their closely related species were within the ranges of 76.5 %-77.2 % and 20.9 %-21.8 %, respectively, indicating that strains ZMM04-4T, ZMM04-5 were novel species. In accordance with phylogenetic and genomic as well as phenotypic and chemotaxonomic characterizations, strains ZMM04-4T and ZMM04-5 should be assigned to the genus Mesorhizobium and indentified as a novel species, for which the name Mesorhizobium marinum sp. nov., is proposed. The type strain is ZMM04-4T (=MCCC 1K08883T = KCTC 8273T).

Flavobacterium plantiphilum sp. nov., Flavobacterium rhizophilum sp. nov., Flavobacterium rhizosphaerae sp. nov., Chryseobacterium terrae sp. nov., and Sphingomonas plantiphila sp. nov. isolated from salty soil showing plant growth promoting potential

Members of the genera Flavobacterium, Chryseobacterium and Sphingomonas constitute a group of microorganisms in the rhizosphere associated with plant growth promoting (PGP) features. A polyphasic approach was employed to ascertain the taxonomic status of five selected strains. Overall genome relatedness indices of digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) between the strains and the other members of the genera Flavobacterium, Chryseobacterium and Sphingomonas were found to be below the established thresholds, respectively. Morphological, physiological, and biochemical characteristics of the strains confirmed their status as five novel species. A large variety of genes involved in plant growth promotion and carbohydrate utilization were found in all strains suggesting a contribution of all strains to PGP. Based on the result of the polyphasic characterization, the following names are proposed: Chryseobacterium terrae sp. nov., with the strain ST-37T as the type strain (= CCM 9260T = LMG 32728T); Flavobacterium plantiphilum sp. nov., with the strain ST-87T as the type strain CIP 112180T = DSM 114790T = LMG 32757T); Flavobacterium rhizophilum sp. nov., with the strain ST-75T as the type strain (= CIP 112185T = DSM 114831T = LMG 32758T); Flavobacterium rhizosphaerae sp. nov., with the strain ST-119T as the type strain (CIP 112181T = DSM 114832T = LMG 32756T); and Sphingomonas plantiphila sp. nov. with the strain ST-64 T as the type strain (= CCM 9261T = CIP 112178T = DSM 114515T = LMG 32729T).

Metabolomic and genomic insights into Micromonospora carbonacea subsp. caeruleus for anti-colorectal compound

Cancer is a predominant contributor to global morbidity and mortality, affecting populations worldwide. Marine Micromonospora species have been identified as significant sources of anticancer compounds. This work aimed to perform a polyphasic approach of isolated strain and conduct comparative metabolomic and genomic analyses to identify compounds with anticancer activity. The study utilized a polyphasic approach on isolated strains for anticancer compound identification. Taxonomic analysis of strain 2MTK254 revealed unique pigment and fatty acid patterns, designating it as a novel Micromonospora carbonacea subsp. caeruleus. Its crude extract displayed significant anti-colorectal activity (66.03% inhibition). Molecular network analysis classified metabolites into eight classes, highlighting a polycyclic tetramate macrolactams (PTMs) compound (P1, C29H38N2O4) with 99.31% inhibitory activity against HCT-116 cell lines (IC50 at 0.125 µM). Genome analysis identified 32 biosynthetic gene clusters (BGCs), including unique PTMs BGCs (83% similarity) linked to the P1 compound. Thus, M. carbonacea subsp. caeruleus 2MTK254 holds promise as a source of novel PTMs with anti-colorectal cancer potential. KEY POINTS: • A novel strain of Micromonospora carbonacea subsp. caeruleus 2MTK254 was isolated in Thailand • A new polycyclic tetramate macrolactam (PTM) with anticancer activity was identified in 2MTK254 • The genome of 2MTK254 has unique secondary metabolite gene clusters.

Comamonas squillarum sp. nov., Isolated from Intestine of Red Swamp Crayfish (Procambarus clarkii)

A novel bacterium, designated as strain PR12T, was isolated from intestine of red swamp crayfish (Procambarus clarkii), which appeared as creamy white colonies on TSA plates. Growth occurred at temperatures of 4-37 °C (28-30 °C optimal), pH of 6.0-9.0 (7.0-8.5 optimal), and with 0-4.0% (w/v) NaCl (0-1.5% optimal). The cells were Gram-stain-negative, rod-shaped, non-motile, aerobic, oxidase- and catalase-positive, and chemoorganotrophic. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain PR12T was related to members of the genus Comamonas and shared the highest sequence similarities with Comamonas koreensis KCTC 12005T (99.0%), Comamonas sediminis S3T (98.8%), and Comamonas piscis CN1T (98.0%). Whole genome size of PR12T was 5,111,300 bp and DNA G + C content was 63.5%. The major cellular fatty acids (> 10%) were C16:0, C17:0 cyclo, summed features 3 (C16:1ω6c and/or C16:1ω7c) and summed features 8 (C18:1ω6c and/or C18:1ω7c). The major respiratory quinone was Q-8 and the major polar lipids contained diphosphatidylglycerol (DPG), phosphatidylglycerol (PG) and phosphatidylethanolamine (PE). Based on the digital DNA-DNA hybridization, phylogenetic analysis, average nucleotide identity, average aminoacid identity as well as biochemical characteristics, strain PR12T was clearly distinguishable from all recognized type strains of the genus Comamonas and represents a novel species, for which the name Comamonas squillarum sp. nov. is proposed. The type strain is PR12T (= MCCC 1K08379T = JCM 35896T).

Genomic insights into Marinospirillum alkalitolerans sp. nov., a novel PHB producing bacterium from an Indian impact crater, and an emended description of family Oceanospirillaceae

Two Gram-stain-negative bacterial strains (MEB164T and MEB148), were isolated from haloalkaline waters of Lonar, crater lake, India. The strains were helical, non-spore-forming and motile with polar tufts of flagella. Optimal growth occurred at 37 ℃, at pH 10 and with 3% (w/v) NaCl. 16S rRNA gene sequences of strains (MEB164T and MEB148) demonstrated the highest similarity with Marinospirillum alkaliphilum DSM 21637T (97.8%) followed by Marinospirillum celere DSM 18438T (96%). The genome size of strain MEB164T was determined to be 2.8 Mb with genomic DNA G + C contents of 53.1 mol %. ANI and dDDH values between strain MEB164T and the most closely related type strain M. alkaliphilum DSM 21637T were (72.3% and 21.4 ± 2.3%) while (AAI and POCP) values were (66.8 and 70.8%), respectively. Strain MEB164T exhibited potential for polyhydroxybutyrate (PHB) production, supported by key genes involved in PHB metabolism. Genome analysis further revealed presence of various pH tolerance genes, highlighting its adaptation to Lonar Lake. The predominant cellular fatty acids were summed feature 8 (C18:1 ω7c/C18:1 ω6c), C16:0 and summed feature 3 (C16:1 ω7c/C16:1 ω6c). The major respiratory quinone was ubiquinone-8. The prevalent polar lipids were diaminophosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified amino phospholipids, three unidentified phospholipids and one unidentified lipid. Polyphasic analysis suggests that the two strains constitute a novel species within the genus Marinospirillum (family Oceanospirillaceae), proposed as Marinospirillum alkalitolerans sp. nov. The type strain is MEB164T (= JCM 35957T = MCC 5207T = NCIMB 15458T) and MEB148 (= JCM 35956 = MCC 5212 = NCIMB 15459) is an additional strain.

Ammonifying and phosphorus-solubilizing function of Aliikangiella maris sp. nov. isolated from Phaeocystis globosa bloom and algal-bacterial interactions

Phaeocystis globosa blooms are of escalating global concern due to their substantial ecological impacts on marine ecosystems. Emerging evidence indicates that algae-bacterial interactions play pivotal roles in shaping the ecology and evolution of harmful algal blooms, although much of this interplay remains unexplored. We successfully isolated and propagated two novel bacterial strains from Phaeocystis globosa bloom. Two novel Gram-negative, non-spore-forming, motile, rod-shaped, and yellow-pigmented bacteria were designated strains GXAS 306T and GXAS 311. According to phenotypic, chemotaxonomic, phylogenomic, and comparative genomic analyses data, strains GXAS 306T and GXAS 311 were considered to represent a novel species of the genus Aliikangiella. Genomic analysis revealed that strain GXAS 306T had many potential functions favorable for interacting with algae, and further experimental evidence confirmed the ammonifying and phosphorus-solubilizing function. Co-culture experiments showed that strain GXAS 306T significantly improved algal growth parameters of two typical P. globosa strains (Pg293 and PgV01), particularly under nitrogen or phosphorus deficiency. Specifically, cell densities were observed to increase by 19.6-86.0%, accompanied by substantial enhancements in photosynthetic performance with increases of 8.0-30.6% in F v /F m and 10.9-27.9% in r ETRmax. Overall, these results shed light on intricate relationships between P. globosa and its associated bacterial partners, which may influence the growth characteristics of algae.

Chitinophaga defluvii sp. nov., a Cyhalofop-Butyl-Degrading Bacterium Isolated from Municipal Sludge

A yellow-colored, Gram-stain-negative, non-motile, and rod-shaped bacterium, designated strain H8T, was isolated from municipal sludge in Huaibei, China. Strain H8T was able to grow at 15-37 °C (optimum at 30 °C), pH 6.0-8.0 (optimum at pH 7.0), and 0-2.5% (w/v) NaCl concentration (optimum at 0%). This strain was taxonomically characterized by a polyphasic approach. Based on the 16S rRNA gene sequence analysis, strain H8T represented to the genus Chitinophaga and shared highest sequence similarities with C. arvensicola DSM 3695T (97.5%), C. niastensis JS16-4T (97.3%), C. hostae 2R12T (97.1%), and C. ginsengisegetis Gsoil 040T (96.8%). The 16S rRNA gene similarities with other members of the genus Chitinophaga are less than 96.3%. The only respiratory quinone was a menaquinone with seven isoprene units (MK-7); the major polar lipid was phosphatidylethanolamine; and the predominant fatty acids were iso-C15:0 and C16:1 ω5c. The genome size of strain H8T was 7.6 Mb, with 44.3% G + C content. The DNA-DNA relatedness and the average nucleotide identity values among strain H8T and other relatives were all less than 19.7% and 72.6%, respectively, which fall below the threshold value of 70% and 95% for the strain to be considered as novel. The morphological, physiological, chemotaxonomic, and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbors. Thus, strain H8T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga defluvii sp. nov. is proposed. The type strain is H8T (= CCTCC AB 2023228T = KCTC 102174T).

Metabolites Discovery from Streptomyces xanthus: Exploring the Potential of Desert Microorganisms

The Taklamakan Desert is an extreme environment supporting a unique and diverse microbial community with significant potential for exploration. Strain TRM70308T, isolated from desert soil, shares 98.43% 16S rRNA gene sequence similarity with Streptomyces alkaliterrae OF1T. Polyphasic taxonomy confirmed TRM70308T as a novel species, named Streptomyces xanthus. Genomic analysis revealed that only one of the strain's 25 biosynthetic gene clusters (BGCs) formed a cluster of gene families (CGFs) within the MIBiG database, emphasizing its genomics uniqueness. LC-MS/MS and Feature-Based Molecular Networking (FBMN) identified 33 metabolites across various categories, including alkaloids, saponins, benzoic acids, and benzofurans, most of which remain uncharacterized. Further chemical investigation led to the isolation of one novel compound, aconicarpyrazine C, and four known compounds: thiolutin, dibutyl phthalate, bis(2-ethylhexyl) phthalate, and N-acetyltryptamine. Thiolutin exhibited strong activity against five local fungal pathogens that cause plant diseases, with a production yield of 270 mg/L. These results establish a foundation for pilot-scale thiolutin production and its potential development as an antifungal agent for agricultural applications. Our findings highlight deserts as a valuable source of novel actinomycetes and bioactive natural products with immense potential for future research and development.

Thalassobellus suaedae gen. nov., sp. nov., a marine bacterium of the family Flavobacteriaceae isolated from a halophyte Suaeda japonica

Two Gram-stain-negative, facultative anaerobic, rod-shaped and non-gliding bacteria, designated as HL-DH10T and HL-DH14, were isolated from the halophyte Suaeda japonica in a mudflat, Republic of Korea. Based on the results of 16S rRNA gene pairwise analysis, the two isolates were the members of the family Flavobacteriaceae, and Aestuariibaculum suncheonense SC17T was the most closely related to strains HL-DH10T and HL-DH14 with 96.3% and 95.4% sequence similarity, respectively. The average nt identity and digital DNA-DNA hybridization values between strains HL-DH10T and HL-DH14 and other related species were all less than 79.2% and 21.9%, respectively. The genomic DNA G+C contents of strains HL-DH10T and HL-DH14 were 32.0% and 31.5%, respectively. Cells of these strains showed optimal growth at 25 °C, pH 6.5-7.0 and 2.5-4.0% (w/v) sea salts. The major respiratory quinone was menaquinone-6. The major cellular fatty acids were iso-C15:0 (14.0-16.0%), iso-C15:1 G (10.0-12.0%), iso-C17:0 3-OH (12.4-13.9%), iso-C15:0 3-OH (11.8-14.9%) and anteiso-C15:0 (9.4-10.6%). The polar lipids consisted of phosphatidylethanolamine, an unidentified aminophospholipid, two to three unidentified aminolipids and three unidentified lipids. The comprehensive phylogenetic, genomic, phenotypic and chemotaxonomic results indicate that strains HL-DH10T and HL-DH14 are considered to represent a novel genus of Flavobacteriaceae. Hence, we propose the novel genus Thalassobellus suaedae gen. nov., sp. nov. The type strain is HL-DH10T (=KCCM 90512T=JCM 36598T).

Isolation and characterization of Novosphingobium aquae sp. nov. and Novosphingobium anseongense sp. nov., isolated from freshwater

Two novel Gram-stain-negative, aerobic, heterotrophic, non-motile bacterial strains, designated as AS3R-12T and PS1R-30T, were isolated from freshwater in South Korea. To determine their taxonomic positions, the strains were thoroughly characterized. Genomic analyses, based on 16S rRNA gene and draft genome sequence data, revealed that the two novel isolates, AS3R-12T and PS1R-30T, belonged to the genus Novosphingobium. AS3R-12T showed the highest 16S rRNA gene similarity (97.7%) with Novosphingobium flavum UCT-28T. In addition, PS1R-30T showed 97.9% 16S rRNA gene similarity with Novosphingobium lentum NBRC 107847T. The draft genome of strains AS3R-12T and PS1R-30T consisted of 4 149 275 and 4 969 838 bps, with DNA G+C content of 63.1 and 66.1 mol%, respectively. The average nucleotide identity between two strains and other related species was below 76.2%, and the digital DNA-DNA hybridization values with closely related species were below 20.8%, both lower than the species delineation threshold. Strains AS3R-12T and PS1R-30T contained the ubiquinone Q-10 as the major quinone and displayed a polyamine pattern with spermidine as the predominant polyamine. Additionally, their major fatty acids were characterized by C16:1  ω7c/C16:1  ω6c (summed feature 3) and C18:1  ω7c/C18:1  ω6c (summed feature 8). The major polar lipids of AS3R-12T and PS1R-30T were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), sphingoglycolipid (SGL) and phosphatidylcholine (PC). Moreover, physiological and biochemical results allowed the phenotypic and genotypic differentiation of strains AS3R-12T and PS1R-30T from their closest and other species of the genus Novosphingobium with validly published names. Therefore, AS3R-12T and PS1R-30T represented novel species of the genus Novosphingobium, for which the names Novosphingobium aquae sp. nov. (type strain AS3R-12T=KACC 23096T=LMG 32950T) and Novosphingobium anseongense sp. nov. (type strain PS1R-30T=KACC 23097T=LMG 32951T) are proposed.

Tersicoccus mangrovi sp. nov., a novel actinobacterium from mangrove sediment in Semarang city, Indonesia

A Gram-stain-positive, aerobic and non-motile actinobacterium, designated strain MR15.9T, was isolated from sediment collected from a mangrove ecosystem in Semarang city, Indonesia. Strain MR15.9T grew at 4-37 °C (optimum 30 °C), pH 6.0-11.0 (optimum 7.0-8.0), with 0-10% (w/v) NaCl (optimum 0-3%). The genome of strain MR15.9T was 3.67 Mbp with 71.7 mol% G+C content. Phylogenetic analysis based on 16S rRNA gene sequence and genome sequence directed that strain MR15.9T formed a well-supported clade with Tersicoccus solisilvae CGMCC 1.15480T and Tersicoccus phoenicis 1P05MAT and shared the highest similarity to T. solisilvae CGMCC 1.15480T (98.9% sequence similarity) and T. phoenicis 1P05MAT (98.6% sequence similarity). However, the comparative genome analysis between strain MR15.9T and T. solisilvae CGMCC 1.15480T gave average nt identity value of 85.2% and digital DNA-DNA hybridization value of 29.0%, which were below the statistical threshold for the delineation of the species. Chemotaxonomic data showed that the major fatty acids were anteiso-C15:0, anteiso-C17:0 and iso-C16:0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unidentified glycolipids and two unidentified phospholipids. MK-8(H2) and MK-9(H2) were noted as the predominant respiratory quinones in this strain. The results of polyphasic characterization indicated that strain MR15.9T represents a novel species of the genus Tersicoccus. The name Tersicoccus mangrovi sp. nov. is proposed, with the type strain MR15.9T (=MCCC 1K08875T=KCTC 59105T).

Tamlana flava sp. nov., isolated from mangrove sediment and genome-based taxonomic analysis of the genus Tamlana

A novel yellow-coloured bacterial strain MA10T was isolated from mangrove sediment and subjected to polyphasic taxonomic identification. Strain MA10T was Gram-negative, rod-shaped, catalase-positive and oxidase-positive. Carotenoid pigment was present, and flexirubin-type pigment was absent. The 16S rRNA gene of strain MA10T had the highest sequence similarity with Tamlana crocina HST1-43T of 94.5%. The genome size was 3.77 Mbp with a genomic G+C content of 36.3%. The phylogenetic analysis of the 16S rRNA gene sequence and whole-genome sequence showed that strain MA10T belonged to the genus Tamlana of the family Flavobacteriaceae and tightly clustered with T. crocina HST1-43T. The digital DNA-DNA hybridization value and average nucleotide identity value between strain MA10T and T. crocina HST1-43T were 20.4 and 76.7%, respectively. The major menaquinone was MK-6. The major fatty acids (>10 %) were iso-C15:0 (41.6%) and iso-C15:1 G (16.8%). The polar lipids consisted of phosphatidylethanolamine, two unidentified aminolipids and three unidentified lipids. Based on the present polyphasic taxonomic study, strain MA10T was considered to represent a novel species of the genus Tamlana, for which the name Tamlana flava sp. nov. was proposed. The type strain was MA10T (=MCCC 1K09289T=KCTC 102321T). Additionally, the phylogeny of the 16S rRNA gene and whole-genome sequences found that the hitherto described nine species of the genus Tamlana and Algibacter onchidii presented polyphyletic clades, which could be divided into five different genera. The average amino acid identity value of 80% was chosen as the boundary of the five genera. Thus, except for the genus Tamlana, four novel genera named Allotamlana gen. nov., Cognatitamlana gen. nov., Neotamlana gen. nov. and Pseudotamlana gen. nov. were proposed. This study provided valuable taxonomic analysis of the genus Tamlana.

Paenibacillus mesotrionivorans sp. nov., a Mesotrione-Degrading Strain Isolated from Soil

A Gram-stain-positive, facultatively anaerobic, motile with peritrichous flagella, and rod-shaped bacterium, designated as P15T, was isolated from an agricultural soil sample collected in Jiangxi Province, PR China. Strain P15T completely degraded 100 mg/L of mesotrione, a herbicide, within 48 h of incubation. Strain P15T grew at 15-42 °C (optimum 30 °C), pH 6.0-9.0 (optimum 7.0), and 0-4.0% (w/v) NaCl (optimum 1.0%). Strain P15T exhibited less than 93.3% 16S rRNA gene sequence similarity with type strains of genus Paenibacillus. In the phylogenetic tree based on 16S rRNA gene sequences, strain P15T was clustered in genus Paenibacillus and formed a subclade with P. cavernae C4-5T, P. contaminans CKOBP-6T, and P. doosanensis CAU 1005T. The major cellular fatty acids (≥ 5% of the total) were anteiso-C15:0, iso-C16:0, C14:0, C16:0, and iso-C14:0. The predominant respiratory quinone was MK-7. The major polar lipids were diphosphatidylglycerol, phosphatidylglycero, phosphatidylethanolamine, one unidentified glycolipid, one unidentified aminophosphoglycolipid, two unidentified aminophospholipids, two unidentified phospholipid, and two unidentified lipids. The diagnostic diamino acid of the peptidoglycan was meso-diaminopimelic acid. The DNA G + C content was 53.9 mol%. Based on the phylogenetic, phenotypic, and chemotaxonomic characteristics, strain P15T represents a novel species within genus Paenibacillus, for which the name Paenibacillus mesotrionivorans sp. nov is proposed, with strain P15T (= MCCC 1K09191T = KCTC 43705T) as the type strain.

Discovery of two novel Flavobacterium species with potential for complex polysaccharide degradation

Polysaccharides are recognized for their extensive biological functions, holding significant promise for applications in both medicine and food industries. However, their utilization is frequently constrained by challenges such as high molecular weights and indistinct sugar chain structures. Recently, two novel bacterial strains, N6T and J3T, were isolated from the Nakdong River in Korea. These strains, which belong to the phylum Bacteroidota, are Gram-stain-negative, non-motile, aerobic, rod-shaped bacteria and have shown polysaccharide-degrading capabilities. Through comprehensive analyses, including 16S rRNA gene sequencing, whole-genome sequencing, and detailed morphological, physiological, and chemotaxonomic characterizations, these strains have been identified as new species within the genus Flavobacterium. KEGG pathway analysis further confirmed their robust capabilities for carbohydrate utilization. Additional investigations using the dbCAN and dbCAN-PUL databases identified the presence of carbohydrate-hydrolyzing enzymes (CAZymes) and polysaccharide utilization loci (PULs) within these strains, suggesting their potential to degrade various polysaccharides. Subsequent in vitro growth experiments demonstrated that strains N6T and J3T can degrade chitin, β-glucan, κ-carrageenan, and cellulose. Given their diverse polysaccharide degradation abilities, these strains are formally proposed to be named Flavobacterium polysaccharolyticum sp. nov. and Flavobacterium aureirubrum sp. nov. The type strains are designated as N6T (= KCTC 102173T = GDMCC 1.4609T) and J3T (= KCTC 102172T = GDMCC 1.4608T), respectively.

Comparative Genomics Reveals Evidence of the Genome Reduction and Metabolic Potentials of Aliineobacillus hadale Isolated from Challenger Deep Sediment of the Mariana Trench

Hadal zones account for the deepest 45% of oceanic depth range and play an important role in ocean biogeochemical cycles. As the least-explored aquatic habitat on earth, further investigation is still required to fully elucidate the microbial taxonomy, ecological significance, metabolic diversity, and adaptation in hadal environments. In this study, a novel strain Lsc_1132T was isolated from sediment of the Mariana Trench at 10,954 m in depth. Strain Lsc_1132T contains heterogenous 16S rRNA genes, exhibiting the highest sequence similarities to the type strains of Neobacillus drentensis LMG 21831T, Neobacillus dielmonensis, Neobacillus drentensis NBRC 102427T, Neobacillus rhizosphaerae, and Neobacillus soli NBRC 102451T, with a range of 98.60-99.10% identity. The highest average nucleotide identity (ANI), the highest digital DNA-DNA hybridization (DDH) values, and the average amino acid identity (AAI) with Neobacillus sp. PS3-40 reached 73.5%, 21.4%, and 75.54%, respectively. The major cellular fatty acids of strain Lsc_1132T included iso-C15:0, Summed Feature 3 (C16:1ω6c and/or C16:1ω7c), iso-C17:0, anteiso-C15:0, and iso-C17:1ω5c. The respiratory quinone of strains Lsc_1132T was MK-7. The G + C content of the genomic DNA was 40.9%. Based on the GTDB taxonomy and phenotypic data, strain Lsc_1132T could represent a novel species of a novel genus, proposed as Aliineobacillus hadale gen. nov. sp. nov. (type strain Lsc_1132T = MCCC 1K09620T). Metabolically, strain Lsc_1132T demonstrates a robust carbohydrate metabolism with many strain-specific sugar transporters. It also has a remarkable capacity for metabolizing amino acids and carboxylic acids. Genomic analysis reveals a streamlined genome in the organism, characterized by a significant loss of orthologous genes, including those involved in cytochrome c synthesis, aromatic compound degradation, and polyhydroxybutyrate (PHB) synthesis, which suggests its adaptation to low oxygen levels and oligotrophic conditions through alternative metabolic pathways. In addition, the reduced number of paralogous genes in strain Lsc_1132T, together with its high protein-coding gene density, may further contribute to streamlining its genome and enhancing its genomic efficiency. This research expands our knowledge of hadal microorganisms and their metabolic strategies for surviving in extreme deep-sea environments.

Neobacillus driksii sp. nov. isolated from a Mars 2020 spacecraft assembly facility and genomic potential for lasso peptide production in Neobacillus

During microbial surveillance of the Mars 2020 spacecraft assembly facility, two novel bacterial strains, potentially capable of producing lasso peptides, were identified. Characterization using a polyphasic taxonomic approach, whole-genome sequencing and phylogenomic analyses revealed a close genetic relationship among two strains from Mars 2020 cleanroom floors (179-C4-2-HS, 179-J1A1-HS), one strain from the Agave plant (AT2.8), and another strain from wheat-associated soil (V4I25). All four strains exhibited high 16S rRNA gene sequence similarity (>99.2%) and low average nucleotide identity (ANI) with Neobacillus niacini NBRC 15566T, delineating new phylogenetic branches within the genus. Detailed molecular analyses, including gyrB (90.2%), ANI (86.4%), average amino acid identity (87.8%) phylogenies, digital DNA-DNA hybridization (32.6%), and percentage of conserved proteins (77.7%) indicated significant divergence from N. niacini NBRC 15566T. Consequently, these strains have been designated Neobacillus driksii sp. nov., with the type strain 179-C4-2-HST (DSM 115941T = NRRL B-65665T). N. driksii grew at 4°C to 45°C, pH range of 6.0 to 9.5, and 0.5% to 5% NaCl. The major cellular fatty acids are iso-C15:0 and anteiso-C15:0. The dominant polar lipids include diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and an unidentified aminolipid. Metagenomic analysis within NASA cleanrooms revealed that N. driksii is scarce (17 out of 236 samples). Genes encoding the biosynthesis pathway for lasso peptides were identified in all N. driksii strains and are not commonly found in other Neobacillus species, except in 7 out of 26 recognized species. This study highlights the unique metabolic capabilities of N. driksii, underscoring their potential in antimicrobial research and biotechnology.

IMPORTANCE

The microbial surveillance of the Mars 2020 assembly cleanroom led to the isolation of novel N. driksii with potential applications in cleanroom environments, such as hospitals, pharmaceuticals, semiconductors, and aeronautical industries. N. driksii genomes were found to possess genes responsible for producing lasso peptides, which are crucial for antimicrobial defense, communication, and enzyme inhibition. Isolation of N. driksii from cleanrooms, Agave plants, and dryland wheat soils, suggested niche-specific ecology and resilience under various environmentally challenging conditions. The discovery of potent antimicrobial agents from novel N. driksii underscores the importance of genome mining and the isolation of rare microorganisms. Bioactive gene clusters potentially producing nicotianamine-like siderophores were found in N. driksii genomes. These siderophores can be used for bioremediation to remove heavy metals from contaminated environments, promote plant growth by aiding iron uptake in agriculture, and treat iron overload conditions in medical applications.

Phylogenetic analysis, metabolic profiling, and environmental adaptation of strain LCG007: a novel Rhodobacteraceae isolated from the East China Sea intertidal zone

Strain LCG007, isolated from Lu Chao Harbor's intertidal water, phylogenetically represents a novel genus within the family Rhodobacteraceae. Metabolically, it possesses a wide array of amino acid metabolic genes that enable it to thrive on both amino acids or peptides. Also, it could hydrolyze peptides containing D-amino acids, highlighting its potential role in the cycling of refractory organic matter. Moreover, strain LCG007 could utilize various carbohydrates, including mannopine and D-apiose-compounds primarily derived from terrestrial plants-demonstrating its capacity to degrade terrestrial organic matter. It could assimilate ammonia, nitrate and nitrite, and utilizes organic nitrogen sources such as polyamines, along with diverse organic and inorganic phosphorus and sulfur sources. Importantly, unlike very limited Sulfitobacter species that possess photosynthetic genes, the genomes of strain LCG007-affiliated genus and all Roseobacter species harbor photosynthetic gene clusters. This conservation was further supported by the significant impact of light on the growth and cell aggregation of strain LCG007, suggesting that acquirement of photosynthetic genes could play a crucial role in the speciation of their common ancestor. In terms of environmental adaptability, the genes that encode for DNA photolyase, heat and cold shock proteins, and enzymes responsible for scavenging reactive oxygen species, along with those involved in the uptake and biosynthesis of osmoprotectants such as betaine, γ-aminobutyric acid (GABA), and trehalose collectively enable strain LCG007 to survive in the dynamic and complex intertidal zone environment. Besides, the capacity in biofilm formation is crucial for its survival under conditions of oligotrophy or high salinity. This study enhances our comprehension of the microbial taxonomy within the Roseobacter clade affiliated cluster, their survival strategies in intertidal ecosystems, and underscores the significance of their role in nutrient cycling. It also highlights the crucial importance of photosynthetic metabolism for the speciation of marine bacteria and their ecological resilience.

Limnobacter olei sp. nov., a Novel Diesel-Degrading Bacterium Isolated from Oil-Contaminated Soil

A bacterial strain P1T, capable of degrading diesel and converting thiosulfate to sulfate was isolated from an oil-contaminated soil sample. The cells were Gram-stain-negative, slightly curved rods and motile with a single polar flagellum. Growth of the strain was observed at 4-45 °C (optimum at 28 °C), at pH 4.0-12.0 (optimum at pH 10.0) and with 0-15.0% (w/v) NaCl (optimum at 2.0%). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain P1T was closely related to the members of the genus Limnobacter, with the highest sequence similarity to Limnobacter thiooxidans DSM 13612 T (99.8%), followed by Limnobacter alexandrii LZ-4 T (99.4%), Limnobacter parvus YS8-69 T (98.8%), Limnobacter litoralis KP1-19 T (97.6%), and Limnobacter humi UCM-39 T (97.5%). The draft genome sequence of strain P1T was 3.40 Mb long, with a DNA G + C content of 52.4%. The average nucleotide identity and digital DNA-DNA hybridization values between strain P1T and the closely related type strains were in the range of 71.8-85.1% and 18.1-28.7%, respectively. The predominant cellular fatty acids of strain P1T included C16: 0, summed feature 3 (C16: 1 ɷ7c and/or C16: 1 ɷ6c), summed feature 8 (C18: 1 ɷ7c and/or C18: 1 ɷ6c), and summed feature 7 (C19: 1 ɷ6c and/or C19: 1 ɷ7c and/or C19: 1 cyclo). In addition, the main polar lipid was composed of diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylglycerol. Q-8 was the sole respiratory quinone. Based on the polyphasic characterization, strain P1T (= KCTC 72814 T = CCTCC AB 2019403 T) represents a novel species of the genus Limnobacter, for which the name Limnobacter olei sp. nov. is proposed.

Luteimonas salinilitoris sp. nov., isolated from the shore soil of saline lake in Tibet of China

Five aerobic, Gram-stain-negative bacterial strains, designated as C3-2-a3T, B3-2-R+30, C3-2-a4, C3-2-M3 and C3-2-M8, were isolated from the coastal soil of LungmuCo Lake in the Tibet Autonomous Region, PR China. Phylogenetic analyses based on 16S rRNA genes and genomes indicated that these isolates belonged to the genus Luteimonas and showed a high similarity to Luteimonas suaedae LNNU 24178T (99.01%), Luteimonas endophytica RD2P54T (98.80%) and Luteimonas salinisoli SJ-92T (97.67%). The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain C3-2-a3T and related reference strains Luteimonas suaedae LNNU 24178T, Luteimonas endophytica RD2P54T and Luteimonas salinisoli SJ-92T were 91.89, 83.11 and 83.86% and 46.90, 26.90 and 28.20%, respectively. All values were below the thresholds for delineating species, supporting their classification as novel species of the genus Luteimonas. The genomic DNA G+C content of strains C3-2-a3T was 68.39%. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and two unidentified phospholipids. The predominant respiratory quinone was ubiquinone-8 (Q-8), aligning with the characteristics of members of the genus Luteimonas. The major fatty acids (>10.0%) of strain C3-2-a3T were identified as iso-C11 :  0, iso-C15 :  0, iso-C16 : 0 and iso-C17 : 1  ω9c. Based on the results of phenotypic, physiological, chemotaxonomic and genotypic characterizations, we propose that the isolates represent a novel species of genus Luteimonas, for which the name Luteimonas salinilitoris sp. nov is proposed. The type strain is C3-2-a3T (=CGMCC 1.14507T=KCTC 8642T).

Lentilactobacillus terminaliae sp. nov., isolated from tree bark (Terminalia ivorensis Chev.) and its antioxidant activity

A Gram-stain-positive, facultatively anaerobic, rod-shaped strain, designated SPB1-3T, was isolated from tree bark. This strain exhibited heterofermentative production of dl-lactic acid from glucose. Optimal growth was observed at 25-40 °C, pH 4.0-7.0, and in the presence of 3% (w/v) NaCl. The cell wall peptidoglycan contained lysine and aspartic acid. The predominant fatty acids identified were C16:0 and the Summed feature 7 (C19 :1  ω7c/C19:1  ω6c and/or C19:1  ω6c/ω7c/19cy). The polar lipid profile included phosphatidylglycerol, diphosphatidylglycerol and phosphatidylinositol, along with two unidentified phospholipids, two unidentified amino lipids and two unidentified lipids. Phylogenetic analysis based on 16S rRNA gene sequences positioned strain SPB1-3T within the genus Lentilactobacillus, showing a close relation to Lentilactobacillus kosonis NBRC 111893T (99.86%) and Lentilactobacillus curieae CCTCC M 2011381T (98.65%). The whole genome of strain SPB1-3T comprised 1 932 998 base pairs with 1955 coding genes and a DNA G+C content of 37.8%. Digital DNA-DNA hybridization between strain SPB1-3T and closely related type strains ranged from 19.50 to 27.20%. The average nucleotide identity ranged from 84.21 to 85.56%, and the average amino acid identity ranged from 57.25 to 85.99%, both falling below the established thresholds for species delineation. Strain SPB1-3T was clearly distinguishable from related Lentilactobacillus species based on its phenotypic and chemotaxonomic characteristics, 16S rRNA gene sequence similarity and whole genome analysis. Additionally, the strain exhibited radical scavenging activity at 66.92% and demonstrated 82.32% inhibition in the tyrosinase inhibitory assay. These findings support the classification of strain SPB1-3T as a novel species within the genus Lentilactobacillus, for which the name Lentilactobacillus terminaliae sp. nov. is proposed. The type strain is SPB1-3T (=JCM 35081T=TISTR 10005T).

Ascidiimonas meishanensis sp. nov. and Leptobacterium meishanense sp. nov., two bacteria isolated from marine sediment in the East China Sea

Two Gram-stain-negative, curved-rod-shaped, non-motile and aerobic bacteria W6T and I13T were isolated from marine sediment samples collected from Meishan Island located in the East China Sea. Catalase and oxidase activities and hydrolysis of Tween 40, 60 and 80 were positive for both strains, while nitrate reduction, indole production, methyl red reaction and H2S production were negative. Phylogenetic analyses based on 16S rRNA and genome sequences revealed that strains W6T and I13T formed distinct phylogenetic lineages within the genera Ascidiimonas and Leptobacterium, respectively. Strain W6T showed the closest relatedness to Ascidiimonas aurantiaca N5DA8-2CT with 93.9% 16S rRNA gene sequence similarity, 70.7% average nucleotide identity (ANI), 71.0% average amino acid identity (AAI) and 16.4% digital DNA-DNA hybridization (dDDH) values, while strain I13T was most closely related to Leptobacterium flavescens YM3-301T with 92.1% 16S rRNA gene sequence similarity, 70.5% ANI, 72.1% AAI and 17.2% dDDH values. The two novel strains shared 92.0% 16S rRNA gene sequence similarity to each other and were identified as two distinct species based on 70.7% ANI, 70.4% AAI and 17.1% dDDH values calculated using whole-genome sequences. The genomes of strains W6T and I13T were 4.59 Mbp with a G+C content of 34.5 mol% and 2.38 Mbp with a G+C content of 36.2 mol%, respectively. The only respiratory quinone was menaquinone-6, the major polar lipid was phosphatidylethanolamine and the major cellular fatty acids were iso-C15 : 0, iso-C15 : 1 G and iso-C17 : 0 3-OH. Based on phenotypic, chemotaxonomic and genotypic data, strains W6T and I13T are considered to represent two novel species in the genera Ascidiimonas and Leptobacterium, respectively, in the family Flavobacteriaceae, for which the names Ascidiimonas meishanensis sp. nov. and Leptobacterium meishanense sp. nov. are proposed. The type strains are W6T (=KCTC 102201T=MCCC 1K08928T) and I13T (=KCTC 102202T=MCCC 1K08929T), respectively.

Parafrigoribacterium soli sp. nov. and Parafrigoribacterium humi sp. nov., two novel siderophore-synthesizing species isolated from black soil

Two siderophore-synthesizing species SYSU BS000078T and SYSU BS000231T were isolated from the black soil collected from fields located in Heilongjiang province, China. The results of phylogenetic analysis based on the 16S rRNA gene sequences indicated that these two strains showed the highest sequence similarity to Parafrigoribacterium mesophilum KCTC 19311T (98.61 % and 98.68 %, respectively). The average nucleotide identity (ANI) values between the two strains and other members of the genus Parafrigoribacterium were lower than 95 %, recommended for distinguishing novel prokaryotic species. Cells of strains SYSU BS000078T and SYSU BS000231T were aerobic, motile, Gram-stain-positive and non-spore-forming rods. The colonies of these two strains exhibited a cream pigment, with tidy edges and smooth surfaces. Growth was observed within the temperature range of 4-37 °C (optimal growth at 28 °C) and pH range of 6.0-8.0 (optimal growth at pH 7.0). The predominant polar lipids detected in these two strains included diphosphatidylglycerol and phosphatidylglycerol. The predominant respiratory quinones was MK-9. The major cellular fatty acids (>10 %) were iso-C16:0, anteiso-C15:0, and anteiso-C17:0. The genome size and G + C content of strain SYSU BS000078T were determined to be 2.89 Mbp and 66.5 %, respectively. Meanwhile, SYSU BS000231T exhibited a genome size of 2.81 Mbp, accompanied by a G + C content of 65.8 %. Based on the phenotypic, physiological, genotypic, and phylogenetic data, these two strains represent two novel species of the genus Parafrigoribacterium, which are proposed as Parafrigoribacterium soli sp. nov. SYSU BS000078T (=GDMCC 1.4599T = KCTC 59245T), and Parafrigoribacterium humi sp. nov. SYSU BS000231T (=GDMCC 1.3816T = KCTC 59001T).

Streptomyces yaizuensis sp. nov., a berninamycin C-producing actinomycete isolated from sponge

While screening for antibiotics in a marine sample, we discovered a berninamycin C-producing actinomycete, designated YSPA8T, isolated from a sponge. A polyphasic approach was used to determine the taxonomic position of the strain. Strain YSPA8T formed sympodially branched aerial mycelia that ultimately segment into chains of spores. Comparative and phylogenetic analyses of the 16S rRNA gene sequence showed that strain YSPA8T were closely related to Streptomyces clavuligerus ATCC 27064T (99.66%), Streptomyces amakusaensis NRRL B-3351T (98.69%), Streptomyces inusitatus NBRC 13601T (98.48%), and 'Streptomyces jumonjinensis' JCM 4947 (98.41%). The phylogenetic tree using the 16S rRNA gene sequences, and both phylogenomic trees suggested that the closest relative of strain YSPA8T was S. clavuligerus ATCC 27064T. The average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values between strain YSPA8T and S. clavuligerus ATCC 27064T were 84.1%, 28.9%, and 82.5%, respectively, which were below the thresholds of 95%, 70%, and 95% for a prokaryotic conspecific assignment. The G + C of the strain YSPA8T was 72.6%. Whole-cell hydrolysates of strain YSPA8T contained LL-diaminopimelic acid. The predominant menaquinones were MK-9(H6) (49%) and MK-9(H8) (48%), and the major fatty acids were C16:0 (26.8%), C16:1 ω7c/ω6c (17.2%), iso-C16:0 (16.0%), and iso-C15:0 (12.5%). The major phospholipids were diphosphatidylglycerol, phosphatidylethanolamine, and other unidentified phospholipids. Based on the phenotypic, phylogenetic, genomic, and chemotaxonomic data, strain YSPA8T represents a novel species of the genus Streptomyces, and the proposed name for this species is Streptomyces yaizuensis sp. nov. The type strain is YSPA8T (=NBRC 115866T = TBRC 17196T).

Methylobacterium litchii sp. nov., Methylobacterium guangdongense sp. nov. and Methylorubrum subtropicum sp. nov., isolated from the phyllosphere of litchi

Three aerobic, pink-pigmented, Gram-negative, motile and rod-shaped bacterial strains, designated SD21T, SI9T and SB2T, were isolated from the phyllosphere of healthy litchis collected from three main producing sites of Guangdong Province, PR China. The 16S rRNA gene analysis showed that strains SD21T and SI9T belonged to the genus Methylobacterium (Mtb.) with the highest similarity to Mtb. komagatae DSM 19563T (98.7%) and Mtb. phyllosphaerae CBMB27T (99.8%), respectively, while strain SB2T belonged to the genus Methylorubrum (Mtr.) and showed the highest similarity to Mtr. suomiense DSM 14458T (98.6%). Phylogenomic analysis based on 92 core genes clearly showed that the most closely related type strains of SD21T, SI9T and SB2T were Mtb. komagatae DSM 19563T, Mtb. phyllostachyos ICMP 17619T and Mtr. salsuginis CGMCC 1.6474T, respectively. The ANI and dDDH values between the three isolates and their most closely related type strains were 85.6‒90.1% and 29.5‒40.4%, respectively, much below the threshold values for species delimitation. The isolates showed clear differences from their closely related type strains in terms of growth conditions, enzyme activities, substrates assimilation and contents of the major fatty acids. They all took summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c) as the major fatty acid, ubiquinone 10 as the predominant respiratory quinone and phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine as the major polar lipids. The phenotypic, phylogenetic and chemotaxonomic analyses with genome comparison strongly support that the isolates represent three distinct novel species within the genera of Methylobacterium and Methylorubrum, for which the names Methylobacterium litchii sp. nov., Methylobacterium guangdongense sp. nov. and Methylorubrum subtropicum sp. nov. are proposed, with SD21T (=GDMCC 1.4327T=KCTC 8300T), SI9T (=GDMCC 1.4329T=KCTC 8298T) and SB2T (=GDMCC 1.4328T=KCTC 8299T) as the type strains, respectively.

Sphingomonas arvum sp. nov.: A promising microbial chassis for high-yield and sustainable zeaxanthin biomanufacturing

The yield of natural products from plants is currently insufficient and cannot be considered a sustainable and secure source of supply, especially given the challenges posed by global climate change. Therefore, a biofoundry that can quickly and accurately produce desired materials from microorganisms based on synthetic biology is urgently needed. Moreover, it is important to find new microbial and genetic chassis to meet the rapidly growing global market for high-value-added zeaxanthin. In this study, we aimed to identify the zeaxanthin biosynthetic gene cluster, crtZ-crtB-crtI-crtY, and confirm zeaxanthin production (11,330 μg g-1 dry biomass weight) through genome mining and liquid chromatography/mass spectrometry profiling using the novel zeaxanthin-producing bacteria Sphingomonas sp. strain BN140010T isolated from the subsurface soil of arable land. We report the highest yield among zeaxanthin-producing Sphingomonas strains to date. Moreover, we determined the taxonomic position of BN140010T using a polyphasic approach based on phylogenetic, physiological and chemotaxonomic characteristics, and we proposed Sphingomonas arvum strain BN140010T as a novel strain. Our results provide a zeaxanthin-producing chassis and diverse genetic tools for microbiological zeaxanthin production. Therefore, this research advances our progress towards the goal of lowering the unit cost of zeaxanthin production, making it more accessible for industrial applications.

Dyella aluminiiresistens sp. nov., a Al3+-tolerant bacterium with the ability to inhibit Fusarium oxysporum f. sp. melonis isolated from rhizosphere soil of muskmelon

A bacterial strain, designated as A6T, was isolated from the rhizosphere soil of a healthy muskmelon in Wenchang, Hainan Province, China. The cells of strain A6T were Gram-negative, aerobic, short rod and motile with a single polar flagellum. Strain A6T could tolerate up to 55.0 mM Al3+ and inhibited the growth of Fusarium oxysporum f. sp. melonis, which is the pathogen of muskmelon Fusarium wilt. Growth occurred at 15-37 ℃ (optimum at 30 ℃), pH 4.5-8.0 (optimum pH 6.5) and with 0-3.0 % NaCl (w/v; optimum, 0.5%). Strain A6T shared the highest 16S rRNA gene sequence similarities with Dyella lutea SaT (98.0%), followed by Dyella thiooxydans ATSB10T (98.0%), Frateuria edaphi 5GH9-34T (97.9%), Dyella nitratireducens DHG59T (97.7%), Frateuria defendens DHoT (97.7%) and Frateuria soli 5GH9-11T (97.7%). Phylogenetic trees based on 16S rRNA gene and genomic sequences indicated that strain A6T belonged to the genus Dyella and formed a subclade with Dyella lutea SaT and Dyella thiooxydans ATSB10T. The average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA-DNA hybridization (dDDH) values between A6T and its closely related type strains were 78.8-80.8 %, 70.0-71.7 % and 20.5-22.1 %, respectively. The sole respiratory quinone was ubiquinone-8 (Q-8). The polar lipid profile consisted of diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), two unidentified aminophospholipids (APL1-2) and three unidentified phospholipids (PL1-3). The major cellular fatty acids (≥5 %) were iso-C17 : 0, C16 : 0, summed feature 9 (iso-C17 : 1  ω9c and/or C16 : 0 10-methyl), iso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0. The genome size of strain A6T was 3.7 Mb with a DNA G+C content of 65.1%. Based on the phenotypic, phylogenetic, genotypic and chemotaxonomic features, strain A6T represents a novel species in the genus Dyella, for which Dyella aluminiiresistens A6T sp. nov. is proposed. The type strain is A6T (= GDMCC 1.4640T = KCTC 92542T).

Roseomonas cutis sp. nov., isolated from human epidermis

Five pink-pigmented bacterial strains, isolated from human skin and classified within the genus Roseomonas, were examined. Among them, four were identified as Roseomonas mucosa, while strain OT10T was deemed to be a potential novel species. Strain OT10T exhibited characteristics, such as Gram-stain-negative, oxidase positive, motile, strictly aerobic and rod shaped. The cells had multiple flagella at one end, arranged in a lophotrichous pattern. The predominant cellular fatty acids in OT10T were C18:1 ω7c/C18:1 ω6c and C18:1 2OH; ubiquinone (Q)-10 was identified as the sole quinone. Major polar lipids included phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylcholine and two aminolipids. The G+C content of the genome was determined to be 72.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequence similarities revealed that strain OT10T is closely related to Roseomonas gilardii subsp. gilardii ATCC 49956T (97.7%), Roseomonas gilardii subsp. rosea ATCC BAA-691T (97.7%) and R. mucosa ATCC BAA-692T (97.5%). For the comparative genomic analyses, whole-genome sequencing was also conducted for strain OT10T. Considering the chemotaxonomic, genotypic and phenotypic features, as well as the low average nucleotide identity and digital DNA-DNA hybridization values compared to its closest phylogenomic neighbours, OT10T is proposed to be a novel species named Roseomonas cutis sp. nov., with OT10T designated as the type strain (=KCTC 92087T =JCM 34968T).

Pseudomonas spirodelae, sp. nov., a bacterium isolated from the roots of the aquatic plant Spirodela polyrhiza

A polyphasic taxonomic study was carried out on strain T5W1T, isolated from the roots of the aquatic plant Spirodela polyrhiza. This isolate is Gram-negative, rod-shaped, motile, aerobic and non-pigmented. Nearly complete 16S rRNA gene sequence homology related the strain to Pseudomonas, with 98.4% similarity to P. guineae, P. peli and P. leptonychotis. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) with the closest phylogenetic neighbour of T5W1T showed differences at the species level, further confirmed by differences in several physiological characteristics. The main fatty acids are summed feature 3 (C16 : 1   ω7c and/or C16 : 1   ω6c), C18 : 1   ω7c, and C16 : 0. The DNA G+C content is 59.3 mol%. Q-9 is the primary ubiquinone found, and phosphatidylethanolamine is the dominant polar lipid, with lesser amounts of phosphatidylglycerol, diphosphatidylglycerol and phosphatidylserine. Based on the results obtained, this bacterium is assigned to the genus Pseudomonas as a new species with the name Pseudomonas spirodelae sp. nov., type strain T5W1T (=NRRL B-65714T =DSM 118085T).

Comamonas halotolerans sp. nov., isolated from the faecal sample of a zoo animal, Naemorhedus caudatus

Strain NoAHT (=KACC 23135T=JCM 35999T), a novel Gram-negative, motile bacterium with a rod-shaped morphology, was isolated from the zoo animal faecal samples, specifically the long-tailed goral species Naemorhedus caudatus. The novel bacterial strain grew optimally in a nutrient broth medium under the following conditions: 1-2% (w/v) NaCl, pH 7-8 and 30 °C. The strain NoAHT exhibited high tolerance to NaCl, with the ability to tolerate up to 7% (w/v) NaCl. Based on phylogenetic analyses using 16S rRNA gene sequencing, strain NoAHT was found to have the closest relatedness to Comamonas jiangduensis YW1T (98.5%), Comamonas aquatica ATCC 11330T (97.9%), Comamonas resistens KCTC 82561T (97.9%), Comamonas fluminis CJ34T (97.7%) and Comamonas suwonensis EJ-4T (97.6%). The genome size and genomic DNA G+C content of strain NoAHT were 4.05 Mbp and 55.9 mol%, respectively. A whole-genome-level comparison of strain NoAHT with C. jiangduensis YWT, Comamonas kerstersii LMG 3475T, C. aquatica NBRC 14918T, Comamonas terrigena NBRC 12685T and C. fluminis CJ34T revealed the following orthologous average nucleotide identity values: 80.1, 79.0, 78.6, 76.3 and 75.2%, respectively. The major polar lipids of strain NoAHT were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. Considering our findings in chemotaxonomic, genotypic and phenotypic characteristics, strain NoAHT is identified as a novel species within the genus Comamonas, for which the name Comamonas halotolerans sp. nov. is proposed.

Pseudoalteromonas qingdaonensis sp. nov., isolated from the intestines of Ilyoplax deschampsi

A Gram-stain-negative, aerobic, motile, catalase-positive, oxidase-positive, short rod-shaped marine bacterium, designated as YIC-827T, was isolated from Qingdao, Shandong Province, China. The results showed that cells of strain YIC-827T could grow optimally at 25-35 °C, pH 6.5-7.5 and 2-7% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence showed that the strain YIC-827T was a member of the genus Pseudoalteromonas. The closest relative to this strain was Pseudoalteromonas ruthenica KMM 300T, with a similarity of 98.39%. The digital DNA-DNA hybridization value between the new isolate and phylogenetically related species is 19.6%. Strain YIC-827T could decompose sodium alginate, casein and esters (Tween 20, Tween 40, Tween 60 and Tween 80), but could not hydrolyse starch, cellulose and DNA. The fatty acid profile of a strain consists of a large number of C16:0, C18:1 ω7c and C16:1 ω7c/C16:1 ω6c. The G+C content of the DNA of this strain was determined to be 48.93%. Based on phenotypic characteristics, phylogenetic analysis and DNA-DNA correlation data, the strain YIC-827 T represents a novel species of the genus Pseudoalteromonas with the name Pseudoalteromonas qingdaonensis sp. nov. The type strain of P. qingdaonensis sp. is strain YIC-827T (=MCCC 1K08807T=CGMCC 1.62085T=KCTC 8212T).

Paludibacillus litoralis gen. nov., sp. nov.: a novel species of a novel genus in the family Paracoccaceae, isolated from the sediment of a tidal flat located in Zhoushan, China

A Gram-stain-negative, aerobic and rod-shaped bacterium, designated as HZG-20T, was isolated from a tidal flat in Zhoushan, Zhejiang Province, China. The 16S rRNA sequence similarities between strain HZG-20T and Pikeienuella piscinae RR4-56T, Coraliihabitans acroporae NNCM2T, Parvibaculum indicum P31T and Zhengella mangrovi X9-2-2T were 98.9, 91.7, 91.0 and 91.0%, respectively. Colonies of strain HZG-20T were 1.4 mm in diameter, milky white, round, smooth and convex after cultivating on marine agar at 30 °C for 48 h. Cells were catalase and oxidase-negative. Growth occurred at 15-37 ℃ (optimum, 28 ℃), pH 5.0-9.0 (optimum, pH 6.0-8.0) and with 0-8% (w/v) NaCl (optimum, 1-3%). It contained Menaquinone-8 (H2) as the sole respiratory quinone, and C16:0 (11.8-13.6%), C18:1  ω9c (6.8-13.3%) and C15:0 anteiso (10.9-27.7%) as the major cellular fatty acids. The main polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid, one unidentified aminolipid, one unidentified phosphoglycolipid, two unidentified glycolipids (GL1-GL2) and three unidentified lipids (L1-L3). The genome of strain HZG-20T was 3 835 886 bp in length, comprised 3746 protein-coding genes, with DNA G+C content of 67.1 mol%. The phylogenetic and phylogenomic trees indicated that strain HZG-20T formed an independent and stable clade with P. piscinae RR4-56T. However, the average nucleotide identity, digit DNA-DNA hybridization and average amino acid identity values between strain HZG-20T and P. piscinae RR4-56T, C. acroporae NNCM2T, P. indicum P31T and Z. mangrovi X9-2-2T were 81.6, 71.1, 68.7 and 69.5%; 23.0, 18.5, 17.9 and 17.5%; and 78.2, 56.8, 56.5 and 61.9%, respectively, together with distinct chemotaxonomic features, indicating strain HZG-20T should not be assigned to known genera. As a result, a novel species of a novel genus within the family Paracoccaceae, designated as Paludibacillus litoralis gen. nov., sp. nov., was proposed. The type strain is HZG-20T (MCCC 1K08468T=KCTC 82692T).

Comprehensive genomic and phenotypic characterization of thermophilic bacterium Sinimarinibacterium thermocellulolyticum sp. nov. HSW-8T, a cellulase-producing bacterium isolated from hot spring water in South Korea

A thermophilic cellulase-producing bacterium, strain HSW-8T, isolated from hot spring waters in South Korea, was subjected to a taxonomic analysis. Cells of strain HSW-8T were gram-stain-negative, facultatively anaerobic, rod-shaped, with optimum growth at 45 °C, pH 7.0, in the presence of 0% (w/v) NaCl. Strain HSW-8T showed the highest 16S rRNA gene sequence similarity to Sinimarinibacterium flocculans NH6-24T (97.52%), followed by Fontimonas thermophila DSM 23609T (96.97%), Solimonas flava CW-KD 4T (95.24%), and Solimonas variicoloris DSM 15731T (95.18%). Based on 16S rRNA phylogeny, strain HSW-8T is phylogenetically closely related to Fontimonas thermophila DSM 23609T and Sinimarinibacterium flocculans DSM 104150T and could be distinguished from the type species based on their phenotypic properties. The genome length of strain HSW-8T was 3.32 Mbp with a 67.33% G + C content. The average nucleotide identity and digital DNA-DNA hybridization values between strain HSW-8T and its closely related type strains were 75.4-83.2 and 20.2-26.2%, respectively. Summed feature 8 (C18:1ω7c and/or C18:1ω6c), C16:0, and iso-C16:0 identified the major fatty acids (> 10%). Phosphatidylglycerol and phosphatidylethanolamine were demonstrated as the major polar lipids while the respiratory quinone is ubiquinone-8. Strain HSW-8T exhibited multiple adaptations for survival at high temperatures, including diverse potential motility mechanisms and toxin-antitoxin systems, as evidenced by both phenotypic characteristics and genomic analysis. Based on genotypic and phenotypic features, strain HSW-8T (= KCTC 92765T = GDMCC 1.4313T) represents a novel Sinimarinibacterium species, in which the name Sinimarinibacterium thermocellulolyticum sp. nov. is proposed.

Arvimicrobium flavum gen. nov., sp. nov., A Novel Genus in the Family Phyllobacteriaceae Isolated From Forest Soil

During the study of microbial diversity of forest soil in the Republic of Korea, a yellow pigment-producing, Gram-stain-negative, rod-shaped, motile bacterium was isolated and designated as strain 1W2T. This strain grew at temperature of 10-37 °C, at pH of 5.0-9.0, and at NaCl concentration of 0-3.0% (w/v). The 16S rRNA gene sequencing and genome sequencing revealed that strain 1W2T is a member of the family Phyllobacteriaceae but exhibits low similarity with known genera, suggesting that this strain is a new genus within the family. This strain showed the closest similarity to the genera Mesorhizobium (96.6-96.9%), Aminobacter (96.4 -96.6%), Aquamicrobium (96.5-96.7%), and Pseudaminobacter (96.6-96.7%). The nearest relative of 1W2T was Mesorhizobium shangrilense CCBAU 65327 T with the 16S rRNA gene sequence similarity of 96.9%. The genome size was 5,545,526 bp with DNA G + C content of 64.7%. The values of overall genomic relatedness indices between strain 1W2T and the reference members were 20.4-21.3% for digital DNA-DNA hybridization, 74.0-76.6% for average nucleotide identity, and 68.1-61.2% for amino acids identity. Chemotaxonomic profiling revealed that Q-10 was the sole ubiquinone; summed feature 8 (C18:1ω7c and/or C18:1ω6c), iso-C13:0, and C19:0 cyclo ω8c were the predominant fatty acids; and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylcholine, and phosphatidylethanolamine were the major polar lipids. Based on these data, strain 1W2T represents a novel species of a new genus in the family Phyllobacteriaceae. Accordingly, we proposed the name Arvimicrobium flavum gen. nov., sp. nov., with the type strain 1W2T (= KCTC 92441 T = NBRC 116019 T).

Taxonomic and genomic characterization of a siderophore-producing bacterium, Rhodoligotrophos ferricapiens sp. nov isolated from lettuce cultivation soil

A Gram-stain-negative, aerobic, non-spore-forming, non-motile, coccus-shaped, and red-pigmented bacterial strain designated as CJ14T was isolated from lettuce cultivation soil in Yong-In, South Korea. Strain CJ14T grew optimally on Luria-Bertani agar at 37 ℃ and pH 7.0 in the absence of NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CJ14T belonged to the genus Rhodoligotrophos in the family Rhodoligotrophaceae and was closely related to Rhodoligotrophos defluvii lm1T (98.4% similarity). The genome size of strain CJ14T was 4.8 Mbp consisting of a single contig, and the DNA G + C content of strain CJ14T was 61.8%. The genomic comparison of strain CJ14T to R. defluvii lm1T showed an average nucleotide identity value of 77.9%, and the digital DNA-DNA hybridization value was 22.4%. Genomic analyses revealed that strain CJ14T possessed a gene cluster for ochrobactin biosynthesis, highly homologous to the siderophore gene cluster from Nitratireductor thuwali Nit1536T. Strain CJ14T contained ubiquinone (Q-10) as the predominant respiratory quinone. The major cellular fatty acids of strain CJ14T were C16:0, C19:0 cyclo ω8c and summed feature 8. The polar lipid profile was composed of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, diphosphatidylglycerol, one unidentified aminolipid, one unidentified glycolipid and five unidentified lipids. Based on polyphasic taxonomy study, strain CJ14T could be classified as a novel species of the genus Rhodoligotrophos, for which the name Rhodoligotrophos ferricapiens sp. nov. is proposed. The type strain is CJ14T (= KACC 23063T = JCM 36057T).

Nitrogen-Fixing Paenibacillus haidiansis and Paenibacillus sanfengchensis: Two Novel Species from Plant Rhizospheres

Two strains, M1 and H32 with nitrogen-fixing ability, were isolated from the rhizospheres of different plants. Genome sequence analysis showed that a nif (nitrogen fixation) gene cluster composed of nine genes (nifB nifH nifD nifK nifE nifN nifX hesA nifV) was conserved in the two strains. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strains M1 and H32 are members of the genus Paenibacillus. Strains M1 and H32 had 97% similarity in the 16S rRNA gene sequences. Strain M1 had the highest similarity (97.25%) with Paenibacillus vini LAM 0504T in the 16S rRNA gene sequences. Strain H32 had the highest similarity (97.48%) with Paenibacillus faecis TCIP 101062T in the 16S rRNA gene sequences. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain M1 and its closest member P. vini were 78.17% and 22.3%, respectively. ANI and dDDH values between strain H32 and its closest member P. faecis were 88.94% and 66.02%, respectively. The predominant fatty acid of both strains is anteiso-C15:0. The major polar lipids of both strains are DPG (diphosphatidylglycerol) and PG (phosphatidylglycerol). The predominant isoprenoid quinone of both strains is MK-7. With all the phylogenetic and phenotypic divergency, two novel species Paenibacillus haidiansis sp. nov and Paenibacillus sanfengchensis sp. nov are proposed with the type strain M1T [=GDMCC (Guangdong Culture Collection Centre of Microbiology) 1.4871 = JCM (Japan Collection of Microorganisms) 37487] and with type strain H32T (=GDMCC 1.4872 = JCM37488).

Aurantiacibacter poecillastricola sp. nov., Isolated from the Marine Sponge, Poecillastra wondoensis, and Reclassification of Erythrobacter alti as Aurantiacibacter alti comb. nov

A Gram-stain-negative, facultative anaerobic rods, designated as strain 219JJ12-13T, was isolated from a marine sponge, Poecillastra wondoensis, in Jeju-do, Republic of Korea. The cells displayed catalase and oxidase activity and were non-motile. Strain 219JJ12-13T grew at 10-37°C (optimum, 25-30°C), pH 6.0-8.5 (optimum, pH 7.0-7.5), and in the presence of 0.5-6.0% (w/v) NaCl (optimum, 4.0-5.0%). The polar lipids comprised disphosphatidylglycerol, phosphatidylglycerol, phosphatidylcoline, phosphatidylethanolamine, sphingoglycolipid, two aminophosphoglycolipid, unidentified phospholipid, and two unidentified lipids. The isoprenoid quinone was identified as Q-10, and predominant cellular fatty acids were C17:1 ω6c, summed feature 3 (C16:1 ω7c/C16:1 ω6c), and summed feature 8 (C16:1 ω7c/C18:1 ω6c). The G+C content of the genomic DNA was 63.3%. The 16S rRNA gene and genome sequences-based phylogenetic analyses showed that strain 219JJ12-13T formed a distinct phyletic clade within the genus Aurantiacibacter. Genome relatedness values, including average nucleotide identity and digital DNA-DNA hybridization among strain 219JJ12-13T and closely related type strains, were 74.0-80.2% and 18.2-22.8%, respectively, both markedly below the thresholds for species delineation. Based on polyphasic taxonomic approach, strain 219JJ12-13T represents a novel species of the genus Aurantiacibacter, and the name Aurantiacibacter poecillastricola sp. nov. is proposed. The type strain is 219JJ12-13T (= KACC 23236T = LMG 33060T). The reclassification of Erythrobacter alti to the genus Aurantiacibacter as Aurantiacibacter alti comb. nov. is also proposed (= KCCM 90261T = NBRC 111903T).

Thalassotalea aquiviva sp. nov., and Thalassotalea maritima sp. nov., Isolated from Seawater of the Coast in South Korea

Two novel bacterial strains, 273M-4T and Sam97T, were isolated from seawater in the Yellow Sea, Muan-gun, South Korea, and identified as members of the genus Thalassotalea. Both strains were Gram-stain-negative, aerobic, rod-shaped, non-motile, non-flagellated, and oxidase- and catalase-positive. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains 273M-4T and Sam97T were most closely related to Thalassotalea ponticola KCTC 42155T, with sequence similarities of 97.5% and 98.3%, respectively. Optimal growth for strain 273M-4T occurred at 25-30 °C, pH 7.0, and 2% NaCl, while strain Sam97T grew optimally at 30 °C, pH 8.0, and 2% NaCl. Genome sizes of strains 273M-4T and Sam97T were 3.37 and 3.31 Mb, with DNA G + C contents of 41.0 mol% and 42.9 mol%, respectively. The orthologous average nucleotide identity (OrthoANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 71.6% and 24.4%, respectively, indicating that they are distinct species. Further genomic analyses of these two strains revealed OrthoANI values of < 73.5% and dDDH values of < 26.7% within the genus Thalassotalea, suggesting their distinctiveness from other Thalassotalea species. The predominate fatty acids of strains 273M-4T and Sam97T were summed feature 3 (consisting of C16:1 ω7c/C16:1 ω6c) and C16:0. All strains contained phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids and ubiquinone-8 (Q-8) as the primary respiratory quinone. Based on phenotypic, phylogenetic, genotypic, and chemotaxonomic data, strains 273M-4T (= KCTC 8644T = LMG 33695T) and Sam97T (= KCTC 8645T = LMG 33694T) represent novel species of the genus Thalassotalea, named Thalassotalea aquiviva sp. nov. and Thalassotalea maritima sp. nov..

Sphingomonas longa sp. nov., Sphingomonas mollis sp. nov. and Sphingomonas aurea sp. nov.: three novel Sphingomonas species isolated from soil

Three Gram-negative, aerobic and non-motile bacterial strains, BT552T, BT553T and KR1UV-12T, were isolated from soil samples in Gwangju-si and Gangneung-si, the Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequence showed that strains BT552T, BT553T and KR1UV-12T clustered to a distinct clade within the family Sphingomonadaceae (order Sphingomonadales, class Alphaproteobacteria). The strains exhibited the highest genetic similarity with representatives of the genus Sphingomonas; moreover, strains BT552T and BT553T tightly clustered with Sphingomonas melonis DAPP-PG 224T (98.2 and 98.1 %) and Sphingomonas aquatilis JSS-7T (98.1 and 98.0 %), while strain KR1UV-12T clustered with S. melonis DAPP-PG 224T (97.9%) and Sphingomonas rubra BH3T (97.8%), respectively. The major cellular fatty acids of all three strains were summed feature 8 (C18:1 ω7c/C18:1 ω6c), comprising 44.7, 46.4 and 48.5%. Additionally, their respiratory quinone is Q-10, and polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phospholipids, sphingolipid and phosphatidylcholine. They all grow well at an optimum temperature of 25 °C, at pH 7. The draft genomes of strains BT552T, BT553T and KR1UV-12T measures 4 035 561 bp, 3 941 714 bp and 3 418 792 bp, respectively, comprising 3 804 3648 and 3236 coding sequences and 50, 48 and 45 RNA genes. The average nucleotide identity analysis and digital DNA-DNA hybridization values between BT552T, BT553T and KR1UV-12T and closely related Sphingomonas species range from 72.7 to 80.2% and 19.4 to 24.3%, respectively. Based on phenotypic, genotypic and chemotaxonomic data, these three strains BT552T, BT553T and KR1UV-12T represent three novel bacterial species within the genus Sphingomonas for which the names Sphingomonas longa sp. nov. (type strain BT552T= KCTC 82094T =NBRC 114993T), Sphingomonas mollis sp. nov. (type strain BT553T =KCTC 82095T =NBRC 114994T) and Sphingomonas aurea sp. nov. (type strain KR1UV-12T = KCTC 92959T = TBRC 18506T) are proposed.

Dictyobacter halimunensis sp. nov., a new member of the phylum Chloroflexota, from forest soil in a geothermal area

Three Gram-stain-positive aerobic bacteria, characterized by branched mycelia with putative sporangia, were isolated from forest soil inside a decayed bamboo stem from a geothermal area in West Java, Indonesia. The strain S3.2.2.5T grew at 15-37 °C (optimum 30 °C), at pH 5.0-7.0 (optimum 7.0) and in the presence of 0-1% NaCl (optimum 0%). Strain S3.2.2.5T was able to hydrolyse cellulose, xylan, starch and skim milk. The cell-wall sugars were composed of xylose and mannose, and the peptidoglycan hydrolysates contained d-glutamic acid, glycine, d-alanine, l-alanine, β-alanine and l-ornithine. The major fatty acids (>10%) were anteiso-C17:0, iso-C17:0, C16:1 2-OH and iso-C16:1. The major polar lipids were phosphatidylinositol, phosphatidylglycerol, diphosphatidylglycerol, unidentified glycolipids and unidentified phospholipids. The major menaquinone was MK-9 (H2). The results of the analysis of the phylogenetic tree based on the 16S rRNA gene indicated that these three isolates belong to the genus Dictyobacter and they were most closely related to the type strain of species Dictyobacter aurantiacus S-27T (97.41-98.00%). The strain S3.2.2.5T exhibited a genome size of 9.41 Mbp, which was significantly larger than the known Dictyobacter species. The G+C content was 54.3 mol%. The average nucleotide identity (90.77%) and the digital DNA-DNA hybridization values (42.6%) between strain S3.2.2.5T and D. aurantiacus S-27T were below the threshold value for species delineation. Based on the phenotypic, chemotaxonomic and molecular characteristics of strain S3.2.2.5T, a novel species of the genus Dictyobacter, for which the name Dictyobacter halimunensis sp. nov., is proposed. The type strain is S3.2.2.5T (= UICC B-128T = CGMCC 1.61913T = KCTC 43728T).

Actinomadura monticuli sp. nov., isolated from Darangshi Oreum (a volcanic cone), and the reclassification of Actinomadura glauciflava Lu et al. 2003 as a later heterotypic synonym of Actinomadura luteofluorescens (Shinobu 1962) Preobrazhenskaya et al. 1975 (Approved Lists 1980)

Two mycelium-forming actinobacterial strains, designated as DLS-47 and DLS-62T, were isolated from volcanic ash collected from the surface of a rock on the peak of Darangshi Oreum (a volcanic cone) in Jeju, Republic of Korea, and their taxonomic positions were investigated by a polyphasic approach. Both of the isolates showed growth at 20-42 °C, pH 6.0-9.0 and 0-1% (w/v) NaCl. Furthermore, DLS-47 was found to grow at 45 °C, while strain DLS-62T grew at pH 10.0 and 3% (w/v) NaCl. The 16S rRNA gene-based phylogeny showed that both of the isolates belonged to the genus Actinomadura; strain DLS-47 was most closely related to Actinomadura chokoriensis DSM 45346T (100% sequence identity), while strain DLS-62T formed a tight cluster with Actinomadura bangladeshensis DSM 45347T (99.5% sequence similarity). Morphological and chemotaxonomic characteristics supported the affiliation of the two isolates to the genus Actinomadura. Phylogenomic analysis based on 92 core gene sequences showed that both of the isolates were most closely related to A. chokoriensis DSM 45346T. Strain DLS-47 shared 100% of orthologous average nucleotide identity and digital DNA-DNA hybridization values with A. chokoriensis DSM 45346T, while strain DLS-62T showed orthologous average nucleotide identity ≤89.8% and digital DNA-DNA hybridization values ≤39.4% with strain DLS-47 and members of the genus Actinomadura. The results of phenotypic assays and comparison of overall genomic relatedness indices support the conclusion that strain DLS-47 (= KACC 23347=DSM 116423) is a strain of A. chokoriensis, while strain DLS-62T (= KACC 23345T = DSM 116424T) represents a new species of the genus Actinomadura, for which the name Actinomadura monticuli sp. nov. is proposed. Also, Actinomadura glauciflava Lu et al. 2003 is reclassified as a later heterotypic synonym of Actinomadura luteofluorescens (Shinobu 1962) Preobrazhenskaya et al. 1975 (Approved Lists 1980) based on analysis of overall genomic relatedness indices and phenotypic similarity.

Geodermatophilus maliterrae sp. nov., a member of the Geodermatophilaceae isolated from badland surfaces in the Red Desert, Wyoming, USA

A novel Gram-stain-positive, black-pigmented bacterium, designated as WL48A T, was isolated from the surface of badland sedimentary rock in the Red Desert of Wyoming and characterized using a polyphasic taxonomic approach. Good growth occurred at 28-32 °C, pH 7-9, and NaCl less than 1% (w/v). Colonies, growing well on International Streptomyces Project media (ISP) 3 and ISP 7, were black and adhering to the agar. Phylogenetic analyses based on 16S rRNA gene and draft genome sequences showed that strain WL48AT belongs to the family Geodermatophilaceae, forming a distinct sub-branch with Geodermatophilus bullaregiensis DSM 46841T. The organism showed 16S rRNA gene sequence similarity of 98.8% with G. bullaregiensis DSM 46841T. Digital DNA-DNA hybridization value between the genome sequences of strain WL48A T and G. bullaregiensis DSM 46841T was 51.8%, below the threshold of 70% for prokaryotic species delineation. The chemotaxonomic investigation revealed the presence of galactose, glucose, mannose, xylose and ribose as well as meso-DAP in the peptidoglycan layer. The polar lipid profiles contained phosphatidylcholine (PC), phosphatidylinositol (PI), diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE) phosphoglycolipid, phospholipids and an unidentified lipid. The menaquinone profile consisted of MK-9(H4) (98.2%) and MK-9(H2) (10.8%). The major fatty acid profile (>15%) comprised iso-C15 : 0 and iso-C16 : 0. Based on phenotypic, genetic and genomic data, strain WL48AT (=DSM 116197T = NCIMB 15483T=NCCB 100957T =ATCC TSD-376T) merits to be considered as a novel species for which the name Geodermatophilus maliterrae sp. nov. is proposed.

Amycolatopsis heterodermiae sp. nov. and Actinacidiphila polyblastidii sp. nov., two new actinobacteria isolated from foliose lichens

Two novel actinomycete strains, designated as V23-08T and V4-01T, were isolated from a foliose lichen collected in Doi Inthanon National Park, Chiang Mai Province, Thailand. Strain V23-08T showed the highest similarity (98.40%) to Amycolatopsis tolypomycina DSM 44544T. Similarly, strain V4-01T showed the highest 16S rRNA gene similarity relatedness (98.89%) to Actinacidiphila acidipaludis PLK6-54T. Chemotaxonomic analysis revealed distinct characteristics for each strain. The isomers of diaminopimelic acid were identified as meso-DAP in strain V23-08T and ll -DAP in strain V4-01T. The predominant menaquinones were MK-9(H2) for strain V23-08T and MK-9(H6) and MK-9(H8) for strain V4-01T. Strain V23-08T contained mannose, glucose, galactose and arabinose as whole-cell sugars, with iso-C16:0 as the major fatty acid. The polar lipid profile included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, unidentified aminophospholipids, unidentified phospholipids and unidentified lipids. In contrast, strain V4-01T exhibited glucose and galactose as whole-cell sugars, with iso-C16:0, anteiso-C16:0 and C16:0 as major fatty acids, and a polar lipid composition of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannoside. The taxonomic data, supported by digital DNA–DNA hybridization and average nucleotide identity analyses, confirm that strains V23-08T and V4-01T represent novel species within the genera Amycolatopsis and Actinacidiphila, respectively. Based on these findings, the names Amycolatopsis heterodermiae sp. nov. (strain V23-08T: TBRC 16208T and NBRC 115837T) and Actinacidiphila polyblastidii sp. nov. (strain V4-01T: TBRC 16209T and NBRC 115865T) are proposed.

Description and genomic characterization of Mangrovibrevibacter kandeliae gen. nov. sp. nov., a novel carotenoid-producing endophytic bacterium isolated from branch of mangrove plants

Two Gram-stain-negative, aerobic, motile and short-rod-shaped bacterial strains, designated CSK15Z-1 T and MSK8Z-1, were isolated from branch of Kandelia candel and Rhizophora stylosa, respectively, collected from Shankou Mangrove Nature Reserve in Guangxi, China, and had the ability to produce carotenoid. The 16S rRNA gene sequence similarity, average nucleotide identity (ANI) values, amino acid identity (AAI) values, and the digital DNA-DNA hybridization (dDDH) values between the two strains indicated that they should be affiliated with the same species. The AAI values between the two strains and other related species in the family Aurantimonadaceae ranged between 61.0 and 66.6%. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the two strains belong to the family Aurantimonadaceae and were most closely related to Aurantimonas endophytica EGI 6500337 T and Aureimonas glaciistagni PAMC 27157 T. Phylogenomic analysis based on genome sequences showed that the two strains formed a single and stable branch within the family Aurantimonadaceae. The major respiratory quinone was Q-10. The predominant fatty acids were C18:1ω7c, C19:0 cycle ω8c and C16:0. The polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, an unidentified aminolipid and an unidentified lipid. In accordance with the AAI values, phylogenomic and phylogenetic analysis, phenotypic and chemotaxonomic characteristics, and genomic characterization, strains CSK15Z-1 T and MSK8Z-1 should be considered as a novel genus and species in the family Aurantimonadaceae, for which the name Mangrovibrevibacter kandeliae gen. nov. sp. nov. is proposed. The type strain is CSK15Z-1 T (= MCCC 1K07183T = JCM 34923 T).

Jannaschia ovalis sp. nov., a marine bacterium isolated from a tidal flat sediment in the Republic of Korea

A Gram-stain-negative, non-motile, aerobic, pale-yellow coloured and oval-shaped bacterium designated GRR-S6-38T was isolated from a tidal flat sediment that collected from Garorim Bay of the Yellow Sea, Republic of Korea. Strain GRR-S6-38T grew at 15-40 °C (optimum, 30 °C) at pH 6-9 (optimum, pH 7) and at 2-6% (w/v) NaCl (optimum, 2% NaCl). Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain GRR-S6-38T was closely related to those of J. seosinensis CL-SP26T (98.1%), J. helgolandensis DSM 14858T (97.4%), J. rubra CECT 5088T (97.4%), J. faecimaris DSM 100420T (97.4%), J. marina SHC163T (97.3%), J. donghaensis CECT 7802T (97.2%) and J. pohangensis DSM 19073T (97.1%). The average nucleotide identity and digital DNA-DNA hybridization value between GRR-S6-38T and related type strains were 71.47-78.59% and 17.80-21.40%. Strain GRR-S6-38T was characterized as having Q-10 as the predominant respiratory quinone and the major principle fatty acids (> 10%) were SF 8 (C18:1 ω7c/C18:1 ω6c, 39.3%), C19:0 ω8c cyclo (13.2%) and C18:1 ω7c 11-methyl (10.6%). The polar lipids consisted of diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, an unidentified lipid, two unidentified aminolipids and two unidentified phospholipids. The assembled genome of strain GRR-S6-38T has a total length of 3.32 Mbp, and a G + C content is 69.98%. Based on the polyphasic taxonomic evidence presented in this study, GRR-S6-38T is regarded to represent a novel species within the genus Jannaschia, for which name Jannaschia ovalis sp. nov. is proposed. The type strain is GRR-S6-38T (= KCTC 82518 = KACC 22240 = JCM 36187).

Isoalcanivorax beigongshangi sp. nov., isolated from the fermented grains of Chinese baijiu

A bacterial strain, REN37T, was isolated from fermented grains of Baijiu samples collected from Sichuan, PR China. The cells of strain REN37T was Gram-negative and aerobic. The cellular morphology exhibited rod-shaped cells without flagellum, displaying non-motility. The optimal growth condition was at 32-37 °C, pH 6.0-7.0, and with a NaCl concentration of 1-2% (w/v). Based on the analysis of 16S rRNA gene sequence, strain REN37T was identified to belong to the genus of Isoalcanivorax. Its closest species was Isoalcanivorax pacificus W11-5 T (96.1%). The polar lipids were identified to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, unidentified glycolipid, two unidentified phospholipids. The predominant menaquinone was MK-12. The predominant fatty acids were C15:0 anteiso (49.4%), C16:0 iso (18.1%), C17:0 anteiso (16.5%) and C15:0 iso (9.5%). The digital DNA-DNA hybridization (dDDH), average nucleotide identity (OrthoANI) and average amino acid identify (AAI) values between strain REN37T and its most similar species were 19.2%, 74.0% and 78.0%, respectively. The DNA G + C content of the strain REN37T was 63.0 mol%. Three alkane 1-monooxygenase (alkB1) genes (1152 bp, 1149 bp, 1179 bp) were identified in the genome, indicating that strain REN37T may be associated with efficient oil-degradation capabilities. Based on the results, REN37T represents a novel specie, and the name Isoalcanivorax beigongshangi sp. nov. was proposed. The type strain is REN37T (= GDMCC 1.3120 T = JCM 35319 T).

Roseateles microcysteis sp. nov., Isolated from Co-cultivation of Microcystis aeruginosa and Myriophyllum spicatum

A novel rod-shaped, Gram-stain-negative bacterial strain MS17T was obtained from a co-culture of Microcystis aeruginosa and Myriophyllum spicatum. The examination of the 16S ribosomal RNA gene sequence showed a significant degree of similarity between strain MS17T and Paucibacter sediminis S2-9T (98.4%), Roseateles violae PFR6T (98.1%), 'Roseateles cellulosilyticus' P8T (98.0%), Roseateles aquae APW11T (97.9%), Roseateles oligotrophus CHU3T (97.7%), Roseateles saccharophilus DSM 654T (97.6%), Kinneretia aquatilis CR182T (97.7%), Pelomonas aquatica CCUG 52575T (97.6%), and Roseateles toxinivorans 2C20T (97.0%). Between strain MS17T and the type strains of closely related species, digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values were below 21.9% and 78.48%. The respiratory quinone was ubiquinone Q-8. The main fatty acids (> 10.0%) were C15:1 ω6c, C16:0, C17:0, and summed feature 3 (C16:1 ω7c and/or C16:1 ω6c). The polar lipids comprised phosphatidylethanolamine, unidentified phospholipid, phosphatidylglycerol, unidentified aminophospholipid, unidentified aminolipid, and three unidentified lipids. The genomic G + C content was 65.9%. According to phenotypic characteristics, phylogenetic relationships, and chemotaxonomic data, strain MS17T has been categorized as a newly discovered species belonging to the Roseateles genus, and the name Roseateles microcysteis sp. nov. is suggested. It exhibits distinct biochemical properties that differentiate it from closely related species. The type strain is MS17T (=KCTC 8001T = LMG 33142T).

Nocardioides xinjiangensis sp. nov., a novel species isolated from desert soil

Two novel strains, SYSU D00514T and SYSU D00778, were isolated from desert soil in the Gurbantunggut Desert, Xinjiang Uygur Autonomous Regions, PR China. SYSU D00514T and SYSU D00778 were aerobic, Gram-stain-positive, rod-shaped, catalase-positive and oxidase-negative. SYSU D00514T grew at temperatures ranging from 4 to 37 °C (optimum, 28-30 °C), at pH 6.0-8.0 (optimum, 7.0), and tolerated NaCl concentrations from 0 to 7.5% (optimum, 0.5% w/v). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains SYSU D00514T and SYSU D00778 were closely related to the members of the genus Nocardioides. Two isolates were most closely related to Nocardioides alpinus Cr7-14 T (98.05% and 98.19%). The G + C content of the genomic DNA of strains SYSU D00514T and SYSU D00778 were both 72.8%. Strain SYSU D00514T and the type strains of the genus Nocardioides in the analysis had average nucleotide identity values of 76.8-85.8% as well as digital DNA-DNA hybridization values between 19.5% and 28.0%. The predominant cellular fatty acids of strain SYSU D00514T were C17:1 ω8c, C18:1 ω9c and iso-C16:0. For strain SYSU D00514T, the major polar lipids encompassed diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, an unidentified aminophospholipid and two unidentified aminolipids. The main respiratory quinone of strain SYSU D00514T was MK-8 (H4). Based on the results of polyphasic taxonomic experiments, we propose that strains SYSU D00514T and SYSU D00778 represent a novel species of the genus Nocardioides, with the name Nocardioides xinjiangensis. The type strain is SYSU D00514T (= CGMCC 1.18622 T = MCCC 1K05001T = KCTC 49488 T).

Halobacillus rhizosphaerae sp. nov., a moderately halophilic bacterium with protease activities isolated from the rhizosphere soil of the mangrove Acanthus ebracteatus

A Gram-positive, moderately halophilic, rod-shaped and facultatively anaerobic strain T66T, was isolated from the rhizosphere soil of mangrove Acanthus ebracteatus in Guangxi, China. Strain T66T was observed to grow at 15-40 ℃ (optimum 30 ℃), pH 5-8 (optimum 6-7) and with 2-20% (w/v) NaCl (optimum 6%). The phylogenetic tree of the 16S rRNA gene sequences depicted a cluster of strain T66T to be closely related to Halobacillus litoralis SL-4 T (98.72%), Halobacillus dabanensis D-8 T (98.70%) and Halobacillus campisalis ASL-17 T (98.66%). The phylogenetic analysis based on the 16S rRNA gene sequence showed that strain T66T belonged to the genus Halobacillus and formed a separate branch. The digital DNA-DNA hybridisation and average nucleotide identify values between strain T66T and its related species were 17.80-19.80% and 70.78-73.22%, respectively, which were lower than the threshold recommended for species delineation. The genomic DNA G + C content was 40.9%. The predominant isoprenoid quinone was MK-7, the cell-wall peptidoglycan contained meso-diaminopimelic acid, and the major fatty acids that accounted for more than 10.0% were anteiso-C15:0 (68.4%) and anteiso-C17:0 (13.4%). Phosphatidylglycerol, diphosphatidylglycerol, three unidentified phospholipids and an unidentified glycolipid were found in the polar lipid extraction. Strain T66T could hydrolyse casein and contains several genes (e. g. vanY, vpr, pbpG and elpC) involved in protease. Therefore, strain T66T is salt-tolerant and produces protease, and it may have development and utilisation value in flavouring agents and food curing. Based on phenotypic, chemotaxonomic data and genotypic characteristics, strain T66T represents a novel species of the genus Halobacillus, for which the name Halobacillus rhizosphaerae sp. nov. is proposed. The type strain is T66T (= JCM 36534 T = MCCC 1K08701T).