Winogradskyella pelagia sp. nov., isolated from coastal sediment.

An orange-pigmented, Gram-stain-negative, strictly aerobic, non-flagellated and rod-shaped bacterium, designated strain DF17T, was isolated from coastal sediment collected from Jingzi Wharf, Weihai, PR China. The optimal growth conditions were determined to be at 30 °C, pH 7.5, and in 3 % (w/v) NaCl. According to phylogenetic analysis of the 16S rRNA gene sequence, strain DF17T showed the highest sequence similarity of 96.9 % to Winogradskyella aquimaris KCTC 23502T. The DNA G+C content was 35.8 mol%, and the major fatty acids were iso-C15 : 1 G, iso-C15 : 0, and iso-C17 : 0 3-OH. The major polar lipids were two aminoglycolipids, one phosphatidylethanolamine and four unidentified lipids. The predominant respiratory quinone was menaquinone-6 (MK-6). The average nucleotide identity, digital DNA-DNA hybridization, and amino acid identity values between strain DF17T and other Winogradskyella species were below the species delineation thresholds of 69.35-72.95 %, 16.9-19.6 % and 71.25-78.93 %, respectively. On the basis of its phenotypic, genetic and physiological characteristics, strain DF17T is suggested to represent a novel species of the genus Winogradskyella, for which the name Winogradskyella pelagia sp. nov. is proposed. The type strain is DF17T (MCCC 1H00456T=KCTC 82421T).

Vitamin K2 sensitizes the efficacy of venetoclax in acute myeloid leukemia by targeting the NOXA-MCL-1 pathway.

Promising outcomes have been reported in elder patients with acute myeloid leukemia (AML) using combined therapy of venetoclax (VEN) and azacytidine (AZA) in recent years. However, approximately one-third of patients appear to be refractory to this therapy. Vitamin K2 (VK2) shows apoptosis-inducing activity in AML cells, and daily oral VK2 (menaquinone-4, GlakayR) has been approved for patients with osteoporosis in Japan. We observed a high response rate to AZA plus VEN therapy, with no 8-week mortality in the newly diagnosed AML patients consuming daily VK2 in our hospital. The median age of the patients was 75.9 years (range 66-84) with high-risk features. Patients received AZA 75 mg/m2 on D1-7, VEN 400 mg on D1-28, and daily VK2 45 mg. The CR/CRi ratio was 94.7% (18/19), with a CR rate of 79%. Complete cytogenetic CR was achieved in 15 of 19 (79%) patients, and MRD negativity in 2 of 15 (13%) evaluable CR patients. Owing to the extremely high response rate in clinical settings, we further attempted to investigate the underlying mechanisms. The combination of VK2 and VEN synergistically induced apoptosis in all five AML cell lines tested. VK2, but not VEN, induced mitochondrial reactive oxygen species (ROS), leading to the transcriptional upregulation of NOXA, followed by MCL-1 repression. ROS scavengers repressed VK2 induced-NOXA expression and led to the cancellation of pronounced apoptosis and the downregulation of MCL-1 by VK2 plus VEN. Additionally, knockdown and knockout of NOXA resulted in abrogation of the MCL-1 repression as well as enhanced cytotoxicity by the two-drug combination, indicating that VK2 suppresses MCL-1 via ROS-mediated NOXA induction. These data suggest that the dual inhibition of BCL-2 by VEN and MCL-1 by VK2 is responsible for the remarkable clinical outcomes in our patients. Therefore, large-scale clinical trials are required.

Sphingobacterium tenebrionis sp. nov., isolated from intestine of mealworm.

A bacterial strain designated PU5-4T was isolated from the mealworm (the larvae of Tenebrio molitor) intestines. It was identified to be Gram-stain-negative, strictly aerobic, rod-shaped, non-motile, and non-spore-forming. Strain PU5-4T was observed to grow at 10-40 °C, at pH 7.0-10.0, and in the presence of 0-3.0 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain PU5-4T should be assigned to the genus Sphingobacterium. The 16S rRNA gene sequence similarity analysis showed that strain PU5-4T was closely related to the type strains of Sphingobacterium lactis DSM 22361T (98.49 %), Sphingobacterium endophyticum NYYP31T (98.11 %), Sphingobacterium soli NCCP 698T (97.69 %) and Sphingobacterium olei HAL-9T (95.73 %). The predominant isoprenoid quinone is MK-7. The major fatty acids were identified as iso-C15 : 0, iso-C17 : 03-OH and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and summed feature 9 (iso-C17 : 0 ω9c). The polar lipids are phosphatidylethanolamine, one unidentified phospholipid, and six unidentified lipids. The genomic DNA G+C content of strain PU5-4T is 40.24 mol%. The average nucleotide identity of strain PU5-4T exhibited respective values of 73.88, 73.37, 73.36 and 70.84 % comparing to the type strains of S. lactis DSM 22361T, S. soli NCCP 698T, S. endophyticum NYYP31T and S. olei HAL-9T, which are below the cut-off level (95-96 %) for species delineation. Based on the above results, strain PU5-4T represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium temoinsis sp. nov. is proposed. The type strain is PU5-4T (=CGMCC 1.61908T=JCM 36663T).

Pedobacter faecalis sp. nov., isolated from the faeces of eland, Taurotragus oryx.

Strain ELA7T, a novel Gram-negative, non-motile bacterium with a white pigment and rod-shaped morphology, was isolated from the faeces of an eland at Seoul Grand Park, a zoo in the Republic of Korea. The novel bacterial strain grew optimally in R2A medium under the following conditions: 0 % (w/v) NaCl, pH 8.0, and 34 °C. Based on phylogenetic analyses using 16S rRNA gene sequencing, strain ELA7T was found to have the closest relatedness to Pedobacter ginsengisoli Gsoil 104T (97.8 %), P. frigoris RP-3-15T (97.2 %), P. humi THG S15-2T (97.0 %), P. seoulensis THG-G12T (97.0 %), and P. foliorum LMG 31463T (96.9 %). The genome size and genomic DNA G+C content of strain ELA7T were 3.63 Mbp and 46.5 %, respectively. A whole genome-level comparison of strain ELA7T with P. ginsengisoli Gsoil 104T, P. frigoris RP-3-15T, P. africanus DSM 12126T, and P. psychroterrae RP-1-14T revealed average nucleotide identity values of 72.0, 71.8, 71.9, and 71.6 %, respectively. The major fatty acids were summed feature 3 (comprising C16 : 1 ω7c and/or C16 : 1 ω6c) and MK-7 was the predominant respiratory quinone. The major polar lipids of strain ELA7T were phosphatidylethanolamine, sphingolipid, unidentified aminolipid, unidentified phosphoglycolipid, unidentified glycolipid, and eight unidentified lipids. Considering our chemotaxonomic, genotypic, and phenotypic findings, strain ELA7T (=KACC 23137T=JCM 36003T) is identified as representing a novel species within the genus Pedobacter, for which the name Pedobacter faecalis sp. nov. is proposed.

Arthrobacter horti sp. nov., isolated from mountain soil.

Gram-stain-positive, aerobic, rod-shaped strains, YJM1T and YJM12S, were isolated from Maebong Mountain, Dogok-dong, Gangnam-gu, Seoul, Republic of Korea. Strains YJM1T and YJM12S exhibited growth at 5-35 °C (optimum, 20-30 °C) and pH 6-9 (optimum, pH 7) and in 0-4 % (w/v) NaCl. Strains YJM1T and YJM12S showed highest 16S rRNA gene sequence similarity to the following members of the genus Arthrobacter: A. nanjingensis A33T (98.3 %/98.2 % similarity), A. woluwensis NBRC 107840T (98.2 %/98.1 %), A. humicola KV-653T (97.3 %), A. oryzae KV-651T (97.3 %), and A. globiformis NBRC 12137T (97.2 %). The strains grew well on Reasoner's 2A, nutrient, Mueller-Hinton, yeast-dextrose, and glucose-peptone-meat extract agars. The major polar lipids of strain YJM1T were phosphatidylglycerol, diphosphatidylglycerol, and phosphatidylinositol. The primary respiratory quinone of strain YJM1T was MK-9(H2), and the major fatty acids of strains YJM1T and YJM12S were anteiso-C15 : 0, anteiso-C17 : 0, iso-C15 : 0, and iso-C16 : 0. The DNA G+C content, based on the whole genome sequence of strain YJM1T, was 68.3 mol%. Average nucleotide identity values and digital DNA-DNA hybridization values between strain YJM1T and the reference strains ranged from 75.0 to 92.7 % and from 21.0 to 65.3 %, respectively. Strain YJM1T exhibited antimicrobial activity against Bacillus subtilis and Escherichia coli. Considering the chemotaxonomic, phenotypic, genotypic, and phylogenetic results, we propose the strain YJM1T represents a novel species in the genus Arthrobacter and suggest the name Arthrobacter horti sp. nov. (type strain YJM1T=KACC 23300T=JCM 36483T).

Methylobacterium amylolyticum sp. nov. and Methylobacterium ligniniphilum sp. nov., isolated from soil.

Two pink-pigmented bacteria, designated strains NEAU-140T and NEAU-KT, were isolated from field soil collected from Linyi, Shandong Province, PR China. Both isolates were aerobic, Gram-stain-negative, rod-shaped, and facultatively methylotrophic. 16S rRNA gene sequences analysis showed that these two strains belong to the genus Methylobacterium. Strain NEAU-140T exhibited high 16S rRNA gene sequence similarities to Methylobacterium radiotolerans NBRC 15690T (97.43 %) and Methylobacterium phyllostachyos NBRC 105206T (97.36 %). Strain NEAU-KT exhibited high 16S rRNA gene sequence similarities to M. phyllostachyos NBRC 105206T (99.00 %) and Methylobacterium longum DSM 23933T (98.72 %). A phylogenetic tree based on 16S rRNA gene sequences showed that strain NEAU-140T formed a clade with Methylobacterium aerolatum (95.94 %), Methylobacterium persicinum (95.66 %) and Methylobacterium komagatae (96.87 %), and strain NEAU-KT formed a cluster with M. phyllostachyos and M. longum. The predominant fatty acid in both strains was C18 : 1 ω7c. Both strains contained ubiquinone Q-10 as the only respiratory quinone. The polar lipid profiles of both strains contained diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylcholine. Whole-genome phylogeny showed that strains NEAU-140T and NEAU-KT formed a phyletic line with M. aerolatum, M. persicinum, Methylobacterium radiotolerans, Methylobacterium fujisawaense, Methylobacterium oryzae, Methylobacterium tardum, M. longum and M. phyllostachyos. The orthologous average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain NEAU-140T and its closely related strains were lower than 82.62 and 25.90  %, respectively. The ANI and dDDH values between strain NEAU-KT and its closely related strains were lower than 86.29 and 31.7 %, respectively. The genomic DNA G+C contents were 71.63 mol% for strain NEAU-140T and 69.08 mol% for strain NEAU-KT. On the basis of their phenotypic and phylogenetic distinctiveness and the results of dDDH and ANI hybridization, these two isolates represent two novel species within the genus Methylobacterium, for which the names Methylobacterium amylolyticum sp. nov. (type strain NEAU-140T=MCCC 1K08801T=DSM 110568T) and Methylobacterium ligniniphilum sp. nov. (type strain NEAU-KT=MCCC 1K08800T=DSM 110567T) are proposed.

Flavobacterium adhaerens sp. nov. and Flavobacterium maritimum sp. nov., two novel flavobacteria isolated from the Pearl River Estuary.

Two strains, designated as SYSU M80004T and SYSU M80005T, were isolated from water sampled in the Pearl River Estuary, Guangzhou, Guangdong, PR China. The strains were Gram-stain-negative and aerobic. Strain SYSU M80004T could grow at pH 6.0-8.0 (optimum, pH 7.0), 22-30 °C (optimum, 28 °C) and in the presence of 0-1 % NaCl (w/v; optimum 0 %). Strain SYSU M80005T could grow at pH 6.0-8.0 (optimum, pH 7.0), 4-37 °C (optimum, 28 °C) and in the presence of 0-1 % NaCl (w/v; optimum 0%). Both strains contained MK-6 as the predominant menaquinone. C16 : 0 and iso-C15 : 0 were identified as the major fatty acids (>10 %) of strain SYSU M80004T while strain SYSU M80005T contained iso-C15 : 0 and iso-C17 : 0 3-OH as major fatty acids. Phosphatidylethanolamine was present as the major polar lipid in both strains. The average nucleotide identity and digital DNA-DNA hybridization values between these two strains and their closest relatives were 73.5-79.3 % and 19.6-23.2 %, respectively. Phylogenetic analysis based on the 16S rRNA gene and genomic sequences indicated they belonged to the genus Flavobacterium. Therefore, on the basis of phenotypic, physiological, chemotaxonomic and genomic evidence, two novel species, Flavobacterium adhaerens sp. nov. (type strain=SYSU M80004T=CDMCC 1.4522T=KCTC 102268T) and Flavobacterium maritimum sp. nov. (type strain=SYSU M80005T=CGMCC 1.4523T= KCTC 102269T) are proposed.

Planococcus shenhongbingii sp. nov., Planococcus shixiaomingii sp. nov. and Planococcus liqunii sp. nov., isolated from soil of the Qinghai-Tibet Plateau.

Six novel bacterial strains, designated N016T, N017, N022T, N028, N056T, and N064, were isolated from soil sampled on the Qinghai-Tibet Plateau. Cells were aerobic, orange or yellow, globular or rod-shaped, non-motile, non-spore-forming, Gram-stain-positive, catalase-positive and oxidase-negative. All the isolates were salt-tolerant and could grow in the range of 4-42 °C. Results of phylogenomic analyses based on 16S rRNA gene sequences and core genomic genes showed that the three pairs of strains (N016T/N017, N022T/N028, and N056T/N064) were closely related to the members of the genus Planococcus, and clustered with Planococcus ruber, Planococcus glaciei, and Planococcus chinensis. The digital DNA-DNA hybridization and average nucleotide identity values of the six novel strains with other members of the genus Planococcus were within the ranges of 18.7-53 % and 70.58-93.49 %, respectively, all below the respective recommended thresholds of 70.0 % and 95-96 %. The genomic DNA G+C content of the six strains ranged from 43.5 to 46.0 mol%. The major fatty acids of the six strains were anteiso-C15 : 0, iso-C14 : 0, and C16 : 1 ω7c alcohol. The predominant polar lipids of strains N016T, N022T, and N056T were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. Menaquinones 7 and 8 were the respiratory quinones. The results of the above analyses indicated that the six strains represent three novel species of the genus Planococcus, for which the names Planococcus shenhongbingii sp. nov. (type strain N016T=GDMCC 1.4062T=JCM 36224T), Planococcus shixiaomingii sp. nov. (type strain N022T=GDMCC 1.4063T=JCM 36225T), and Planococcus liqunii sp. nov. (type strain N056T=GDMCC 1.4064T=JCM 36226T) are proposed.

Maribellus mangrovi sp. nov., an iron-reducing bacterium isolated from mangrove sediment.

A novel facultatively anaerobic and Gram-stain-negative bacterium, designated FJH33T, was isolated from mangrove sediment sampled in Zhangzhou, PR China. Cells of strain FJH33T were rod-shaped or slightly curved-shaped, with widths of 0.3-0.5 µm and lengths of 1.0-3.0 µm. Optimum growth of strain FJH33T occurred in the presence of 3 % NaCl (w/v), at 33 °C and at pH 7.0. Oxidase activity was negative, while catalase activity was positive. Its iron-reducing ability was determined. Based on 16S rRNA gene sequence similarity, strain FJH33T was most closely related to Maribellus luteus XSD2T (95.1 %), followed by Maribellus sediminis Y2-1-60T (95.0 %) and Maribellus maritimus 5E3T (94.9 %). Genome analysis of strains FJH33T and M. luteus XSD2T revealed low genome relatedness, with an average nucleotide identity value of 73.8% and a digital DNA-DNA hybridization value of 19.0%. Phylogenetic trees built from 16S rRNA genes and genome sequences showed that strain FJH33T represents a relatively independent phylogenetic lineage within the genus Maribellus. The major cellular fatty acids (≥10 %) were iso-C15 : 0 and C18 : 1 ω9c. The sole respiratory quinone was MK-7. The polar lipids consisted of phosphatidylethanolamine, diphosphatidylcholine, diphosphatidyglycerol and one unidentified lipid. The DNA G+C content was 41.4 mol%. Based on the integrated results of phylogenetic, physiological, biochemical and chemotaxonomic characterizations, we propose that strain FJH33T represents a novel species of the genus Maribellus, for which the name Maribellus mangrovi sp. nov. is proposed. The type strain is FJH33T (=KCTC 102210T=MCCC 1H01459T).

Microbacterium algihabitans sp. nov., Microbacterium phycohabitans sp. nov., and Microbacterium galbum sp. nov., isolated from dried beach seaweeds.

Three actinobacterial strains, KSW2-21T, KSW2-29T and KSW4-17T, were isolated from dried seaweeds collected around Gwakji Beach in Jeju, Republic of Korea. Their taxonomic positions were determined based on genomic, physiological and morphological characteristics. The isolates were Gram-positive, aerobic, non-motile, rod-shaped bacteria characterized by the following chemotaxonomic features: ornithine as the cell wall diamino acid, the N-glycolyl type of murein, MK-11 as the predominant menaquinone, polar lipids including diphosphatidylglycerol, phosphatidylglycerol, two unidentified glycolipids and four unidentified phospholipids, with anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0 as the the major fatty acids. The 16S rRNA gene phylogeny showed that the novel strains formed three distinct sublines within the genus Microbacterium. Strain KSW4-17T formed a tight cluster with the type strain of Microbacterium hydrothermale, while strains KSW2-21T and KSW2-29T occupied distinct positions between the type strains of M. hydrothermale and Microbacterium testaceum. Strains KSW4-17T and KSW2-29T showed 99.9 % rRNA gene sequence similarity to M. hydrothermale CGMCC 1.12512T, while strain KSW2-21T revealed 99.4 % 16S rRNA gene sequence similarity to the type strains of M. hydrothermale and M. testaceum. The genome sizes and genomic G+C contents of the three isolates ranged from 3.44 to 3.74 Mbp and from 70.3 to 70.8 mol%, respectively. The phylogenomic tree based on 92 core gene sequences exhibited similar topologies to the 16S rRNA gene phylogeny. The comparison of overall genomic relatedness indices, such as average nucleotide indentity and digital DNA-DNA hybridization, supported that the isolates represent three new species of the genus Microbacterium. Based on the results obtained here, Microbacterium algihabitans sp. nov. (type strain, KSW2-21T=KACC 23322T=DSM 116381T), Microbacterium phycohabitans sp. nov. (type strain KSW2-29T=KACC 22350T=NBRC 115221T) and Microbacterium galbum sp. nov. (type strain, KSW4-17T=KACC 23323T=DSM 116383T) are proposed.

Flavobacterium facile sp. nov., isolated from water system of Atlantic salmon (Salmo salar) fry cultured in Chile.

Strain T-12T, an orange, Gram-stain-negative, non-motile, rod-shaped strain, was isolated in November 2013 from water samples collected from an Atlantic salmon (Salmo salar) fry culturing system at a fish farm in Chile. Phylogenetic analysis based on 16S rRNA sequences (1394 bp) revealed that strain T-12T belonged to the genus Flavobacterium, showing close relationships to Flavobacterium bernardetii F-372T (99.48 %) and Flavobacterium terrigena DS-20T (98.50 %). The genome size of strain T-12T was 3.28 Mb, with a G+C content of 31.1 mol%. Genome comparisons aligned strain T-12T with Flavobacterium bernardetii F-372T (GCA_011305415) and Flavobacterium terrigena DSM 17934T (GCA_900108955). The highest digital DNA-DNA hybridization (dDDH) values were 42.6 % with F. bernardetii F-372T (GCA_011305415) and 33.9 % with F. terrigena DSM 17934T (GCA_900108955). Pairwise average nucleotide identity (ANI) calculations were below the species cutoff, with the best results with F. bernardetii F-372T being: ANIb, 90.33 %; ANIm, 91.85 %; and TETRA, 0.997 %. These dDDH and ANI results confirm that strain T-12T represents a new species. The major fatty acids were iso-C15 : 0 and C15 : 1ω6с. Detected polar lipids included phospholipids (n=2), aminophospholipid (n=1), aminolipid (n=1) and unidentified lipids (n=2). The predominant respiratory quinone was menaquinone MK7 (80 %) followed by MK-6 (20 %). Phenotypic, chemotaxonomic, and genomic data support the classification of strain T-12T (=CECT 30410T=RGM 3222T) as representing a novel species of Flavobacterium, for which the name Flavobacterium facile sp. nov. is proposed.

Chitinophaga pollutisoli sp. nov., isolated from contaminated sediment.

A Gram-stain-negative, yellow-pigmented, and facultatively aerobic bacterium, designated strain GPA1T, was isolated from plastic waste landfill soil in the Republic of Korea. The cells were non-motile short rods exhibiting oxidase-negative and catalase-positive activities. Growth was observed at 15-40 °C (optimum, 30 °C), at pH 6.0-9.0 (optimum, pH 7.0-8.0) and in the presence of 0-2.5 % (w/v) NaCl (optimum, 0 %). Menaquinone-7 was the sole respiratory quinone, and iso-C15 : 0, C16 : 1 ω5c, and iso-C17 : 0 3-OH were the major cellular fatty acids (>10 % of the total fatty acids). Phosphatidylethanolamine was identified as a major polar lipid. Phylogenetic analyses based on 16S rRNA gene sequences and 120 concatenated marker protein sequences revealed that strain GPA1T formed a distinct lineage within the genus Chitinophaga. The genome of strain GPA1T was 6078 kb in size with 53.8 mol% G+C content. Strain GPA1T exhibited the highest similarity to Chitinophaga rhizosphaerae T16R-86T, with a 98.6 % 16S rRNA gene sequence similarity, but their average nucleotide identity and digital DNA-DNA hybridization values were 82.5 and 25.9 %, respectively. Based on its phenotypic, chemotaxonomic, and phylogenetic characteristics, strain GPA1T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga pollutisoli sp. nov. is proposed. The type strain is GPA1T (=KACC 23415T=JCM 36644T).

Promethearchaeum syntrophicum gen. nov., sp. nov., an anaerobic, obligately syntrophic archaeon, the first isolate of the lineage 'Asgard' archaea, and proposal of the new archaeal phylum Promethearchaeota phyl. nov. and kingdom Promethearchaeati regn. nov.

An anaerobic, mesophilic, syntrophic, archaeon strain MK-D1T, was isolated as a pure co-culture with Methanogenium sp. strain MK-MG from deep-sea methane seep sediment. This organism is, to our knowledge, the first cultured representative of 'Asgard' archaea, an archaeal group closely related to eukaryotes. Here, we describe the detailed physiology and phylogeny of MK-D1T and propose Promethearchaeum syntrophicum gen. nov., sp. nov. to accommodate this strain. Cells were non-motile, small cocci, approximately 300-750 nm in diameter and produced membrane vesicles, chains of blebs and membrane-based protrusions. MK-D1T grew at 4-30 °C with optimum growth at 20 °C. The strain grew chemoorganotrophically with amino acids, peptides and yeast extract with obligate dependence on syntrophy with H2-/formate-utilizing organisms. MK-D1T showed the fastest growth and highest maximum cell yield when grown with yeast extract as the substrate: approximately 3 months to full growth, reaching up to 6.7×106 16S rRNA gene copies ml-1. MK-D1T had a circular 4.32 Mb chromosome with a DNA G+C content of 31.1 mol%. The results of phylogenetic analyses of the 16S rRNA gene and conserved marker proteins indicated that the strain is affiliated with 'Asgard' archaea and more specifically DHVC1/DSAG/MBG-B and 'Lokiarchaeota'/'Lokiarchaeia'. On the basis of the results of 16S rRNA gene sequence analysis, the most closely related isolated relatives were Infirmifilum lucidum 3507LTT (76.09 %) and Methanothermobacter tenebrarum RMAST (77.45 %) and the closest relative in enrichment culture was Candidatus 'Lokiarchaeum ossiferum' (95.39 %). The type strain of the type species is MK-D1T (JCM 39240T and JAMSTEC no. 115508). We propose the associated family, order, class, phylum, and kingdom as Promethearchaeaceae fam. nov., Promethearchaeales ord. nov., Promethearchaeia class. nov., Promethearchaeota phyl. nov., and Promethearchaeati regn. nov., respectively. These are in accordance with ICNP Rules 8 and 22 for nomenclature, Rule 30(3)(b) for validation and maintenance of the type strain, and Rule 31a for description as a member of an unambiguous syntrophic association.

Salinibacterium soli sp. nov., isolated from lakeside soil.

A Gram-stain-positive, rod-shaped, non-spore-forming and non-motile bacterium, designated strain WY-16T. Growth was observed at 20-42 °C (optimum, 30 °C), pH 6-9 (optimum, pH 7) and salinity of 0-3 % (w/v; optimum, 1 %). Phylogenetic analysis based on genome sequences indicated that WY-16T was affiliated to the family Microbacteriaceae and most closely related to Salinibacterium xinjiangense and Salinibacterium amurskyense. The average nucleotide identity values between strain WY-16T and S. xinjiangense and S. amurskyense were 74.7 and 72.5 %, respectively. The digital DNA-DNA hybridization values between strain WY-16T and S. xinjiangense and S. amurskyense were 19.6 and 18.6 %, respectively. The predominant fatty acids were anteiso-C15 : 0, iso-C16 : 0 and iso-C16 : 0 10-methyl. The major menaquinones were MK-12, MK-13, MK-14 and MK-15. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified glycolipid and one unidentified phospholipid. The cell-wall peptidoglycan contained 2,4-diaminobutyric acid as the diamino acid and ribose, rhamnose, glucose and galactose were the major cell-wall sugars. Based on phenotypic, genotypic and phylogenetic evidence, strain WY-16T represents a novel species in the genus Salinibacterium, for which the name Salinibacterium soli sp. nov. is proposed. The type strain is WY-16T (=GDMCC 1.4011T=JCM 36421T).

Actinotalea lenta sp. nov., a novel actinomycete isolated from tidal flat sediment.

Two Gram-stain-positive, aerobic, oxidase- and catalase-negative, non-motile, and short rod-shaped actinomycetes, named SYSU T00b441T and SYSU T00b490, were isolated from tidal flat sediment located in Guangdong province, PR China. The 16S rRNA gene sequence similarity, average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between SYSU T00b441T and SYSU T00b490 were 99.3, 99.5 and 97.1 %, respectively. Strains SYSU T00b441T and SYSU T00b490 exhibited the highest 16S rRNA gene sequence similarities to Actinotalea ferrariae CF 5-4T (97.1 %/98.2 %), with ANI values of 74.01/73.88 % and dDDH values of 20.5/20.4 %. In the phylogenomic tree, the two isolates were affiliated with the genus Actinotalea. The genomes of strains SYSU T00b441T and SYSU T00b490 were 3.31 and 3.34 Mb, and both had DNA G+C contents of 72.8 mol%, coding 3077 and 3085 CDSs, three and three rRNA genes, and 53 and 51 tRNAs, respectively. Growth occurred at 15-40 °C (optimum, 28-30 °C), pH 4.0-10.0 (optimum, 7.0) and in the presence of 0-7 % (w/v) NaCl (optimum, 3 %). The major fatty acids (>10  %) of strains SYSU T00b441T and SYSU T00b490 were anteiso-C15 : 0 and C16 : 0. The major respiratory quinone was identified as MK-10(H4). The polar lipids of strains SYSU T00b441T and SYSU T00b490 were diphosphatidyl glycerol, phosphatidylglycerol, phosphoglycolipid, phosphatidyl ethanolamine, two phosphatidylinositol mannosides, two glycolipids and two phospholipids. Based on these data, the two strains (SYSU T00b441T and SYSU T00b490) represent a novel species of the genus Actinotalea, for which the name Actinotalea lenta sp. nov is proposed. The type strain is SYSU T00b441T (=GDMCC 1.3827T=KCTC 49943T).

Aequorivita sediminis sp. nov. and Aequorivita marina sp. nov., isolated from marine sediment.

Two Gram-stain-negative, rod-shaped, non-motile, strictly aerobic strains, forming yellow colonies and designated F6058T and S2608T, were isolated from marine sediment collected in Weihai, PR China. Both strains grow at 4-40 °C (optimum, 30-33 °C), pH 6.0-7.5 (optimum, pH 6.5) and in the presence of 0-7.0 % (w/v) NaCl. The optimum NaCl concentrations for strains F6058T and S2608T were 2.0 % and 2.5 %, respectively. Phylogenetic analysis of the 16S rRNA gene sequences indicated that strains F6058T and S2608T share an evolutionary lineage with members of the genus Aequorivita. The isolates exhibited a 16S rRNA gene sequence similarity of 96.7 % to each other. Strains F6058T exhibited the highest 16S rRNA gene sequence similarity to Aequorivita xiaoshiensis F64183T (98.8 %), and S2608T was most similar to Aequorivita capsosiphonis A71T (96.9 %). Iso-C15:0, anteiso-C15:0 and iso-C17:0 3-OH were the major fatty acids of strains F6058T and S2608T. The sole respiratory quinone of both isolates was menaquinone 6 (MK-6). The polar lipid profiles of the isolates both consisted of phosphatidylethanolamine and phosphoglycolipids; however, strain F6058T exhibited one glycolipid, one aminolipid and two unidentified polar lipids, and strain S2608T also had two glycolipids and one unidentified polar lipid. The DNA G+C contents of strains F6058T and S2608T were 34.6 % and 37.7 mol%, respectively. Based on their phenotypic, chemotaxonomic and genomic characteristics, strains F6058T and S2608T were considered to represent novel species of the genus Aequorivita, for which the names Aequorivita sediminis sp. nov. and Aequorivita marina sp. nov. were proposed. The type strains are F6058T (=KCTC 92653T=MCCC 1H01358T) and S2608T (KCTC 92652T=MCCC 1H01361T).

Klenkia sesuvii sp. nov., isolated from leaves of halophyte Sesuvium portulacastrum.

During a study on the diversity of culturable actinobacteria from coastal halophytes in Thailand, strain LSe6-5T was isolated from leaves of sea purslane (Sesuvium portulacastrum L.), and a polyphasic approach was employed to determine its taxonomic position. The 16S rRNA gene sequences analysis indicated that the strain was most closely related to Klenkia brasiliensis Tu 6233T (99.2 %), Klenkia marina YIM M13156T (99.1 %), and Klenkia terrae PB261T (98.7 %). The genome of strain LSe6-5T was estimated to be 4.33 Mbp in size, with DNA G+C contents of 74.3%. A phylogenomic tree based on whole-genome sequences revealed that strain LSe6-5T formed a clade with Klenkia marina DSM 45722T, indicating their close relationship. However, the average nucleotide identity (ANI)-blast, ANI-MUMmer, and dDDH values between strain LSe6-5T with K. marina DSM 45722T (87.1, 88.9, and 33.0 %) were below the thresholds of 95-96 % ANI and 70 % dDDH for identifying a novel species. Furthermore, strain LSe6-5T showed morphological and chemotaxonomic characteristics of the genus Klenkia. Cells were motile, rod-shaped, and Gram-stain-positive. Optimal growth of strain LSe6-5T occurred at 28 °C, pH 7.0, and 0-3 % NaCl. The whole-cell hydrolysates contained meso-diaminopimelic acid as the diagnostic diamino acid, with galactose, glucose, mannose, and ribose as whole-cell sugars. The predominant menaquinones were MK-9(H4) and MK-9(H0). The polar lipid profile was composed of diphosphatidylglycerol, hydroxyphosphatidylethanolamine, phosphatidylinositol, glycophosphatidylinositol, an unidentified phospholipid, and an unidentified lipid. Major cellular fatty acids were iso-C15 : 0, iso-C16 : 0, and iso-C17 : 0. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, it is supported that strain LSe6-5T represents a novel species of the genus Klenkia, for which the name Klenkia sesuvii sp. nov. is proposed. The type strain is strain LSe6-5T (=TBRC 16417T= NBRC 115929T).

Svornostia abyssi gen. nov., sp. nov. isolated from the world's deepest silver-uranium mine currently devoted to the extraction of radon-saturated water.

A Gram-stain-positive, rod-shaped, aerobic, motile bacterium, J379T, was isolated from radioactive water spring C1, located in a former silver-uranium mine in the Czech Republic. This slow-growing strain exhibited optimal growth at 24-28 °C on solid media with <1 % salt concentration and alkaline pH 8-10. The only respiratory quinone found in strain J379T was MK-7(H4). C18 : 1 ω9c (60.9 %), C18 : 0 (9.4 %), C16 : 0 and alcohol-C18 : 0 (both 6.2 %) were found to be the major fatty acids. The peptidoglycan contained directly cross-linked meso-diaminopimelic acid. Phylogenetic reconstruction based on the 16S rRNA gene sequences and the core-genome analysis revealed that strain J379T forms a separate phylogenetic lineage within the recently amended order Solirubrobacterales. A comparison of the 16S rRNA gene sequences between strain J379T and other members of the order Solirubrobacterales showed <96 % similarity. This analysis revealed that the closest type strains were Parviterribacter kavangonensis D16/0 /H6T (95.2 %), Capillimicrobium parvum 0166_1T (94.9 %) and Conexibacter arvalis KV-962T (94.5 %). Whole-genome analysis showed that the closest type strain was Baekduia soli BR7-21T with an average nucleotide identity of 78 %, average amino acid identity of 63.2 % and percentage of conserved proteins of 48.2 %. The G+C content of the J379T genomic DNA was 71.7 mol%. Based on the phylogenetic and phylogenomic data, as well as its physiological characteristics, strain J379T is proposed to represent a type strain (DSM 113746T=CCM 9300T) of Svornostia abyssi gen. nov. sp. nov. within the family Baekduiaceae.

Sustainable menaquinone-7 production through continuous fermentation in biofilm bioreactors.

Menaquinone-7 (MK-7), a vital vitamin with numerous health benefits, is synthesized and secreted extracellularly by the formation of biofilm, dominantly in Bacillus strains. Our team developed an innovative biofilm reactor utilizing Bacillus subtilis natto cells to foster biofilm growth on plastic composite supports to produce MK-7. Continuous fermentation in biofilm reactors offers a promising strategy for achieving sustainable and efficient production of Menaquinone-7 (MK-7). Unlike conventional batch fermentation, continuous biofilm reactors maintain a steady state of operation, which reduces resource consumption and waste generation, contributing to sustainability. By optimizing fermentation conditions, MK-7 production was significantly enhanced in this study, demonstrating the potential for sustainable industrial-scale production. To determine the optimal operational parameters, various dilution rates were tested. These rates were selected based on their potential to enhance nutrient supply and biofilm stability, thereby improving MK-7 production. By carefully considering the fermentation conditions and systematically varying the dilution rates, MK-7 production was significantly enhanced during continuous fermentation. The MK-7 productivity was found to increase from 0.12 mg/L/h to 0.33 mg/L/h with a dilution rate increment from 0.007 to 0.042 h-1). This range was chosen to explore the impact of various nutrient supply rates on MK-7 production and to identify the optimal conditions for maximizing productivity. However, a further increase in the dilution rate to 0.084 h-1 led to reduced productivity at approximately 0.16 mg/L/h, likely due to insufficient retention time for effective biofilm formation. Consequently, a dilution rate of 0.042 h-1 exhibited the highest productivity of 0.33 mg/L/h, outperforming all investigated dilution rates and demonstrating the critical balance between nutrient supply and retention time in continuous fermentation. These findings validate the feasibility of operating continuous fermentation at a 0.084 h-1 dilution rate, corresponding to a 48 h retention time, to achieve the highest MK-7 productivity compared to conventional batch fermentation. The significant advancements achieved in enhancing Menaquinone-7 (MK-7) productivity through continuous fermentation at optimal dilution rates in the present work indicate promising prospects for even greater efficiency and sustainability in MK-7 production through future developments.

Mangrovimonas cancribranchiae sp. nov., a novel bacterial species associated with the gills of the fiddler crab Cranuca inversa (Brachyura, Ocypodidae) from Red Sea mangroves.

Two bacteria, UG2_1T and UG2_2, were isolated from the gill tissues of the mangrove fiddler crab Cranuca inversa collected on the east coast of the Red Sea (Thuwal, Saudi Arabia). The cells are Gram-negative, rod-shaped, orange-pigmented, motile by gliding with no flagella, strictly aerobic, and grow at 20-37 °C (optimum, 28-35 °C), at pH 5.0-9.0 (optimum, pH 6.0-7.0), and with 1-11 % (w/v) NaCl (optimum, 2-4 %). They were positive for oxidase and catalase activity. Phylogenetic analysis based on 16S rRNA gene sequences indicated that isolates UG2_1T and UG2_2 belong to the genus Mangrovimonas, showing the highest similarity to Mangrovimonas spongiae HN-E26T (99.4 %). Phylogenomic analysis based on the whole genomes, independently using 49 and 120 concatenated genes, showed that strains UG2_1T and UG2_2 formed a monophyletic lineage in a different cluster from other type strain species within the genus Mangrovimonas. The genome sizes were 3.08 and 3.07 Mbp for UG2_1T and UG2_2, respectively, with a G+C content of 33.8 mol% for both strains. Values of average nucleotide identity and digital DNA-DNA hybridization between the strains and closely related species were 91.0 and 43.5 %, respectively. Chemotaxonomic analysis indicated that both strains had iso-C15 : 0 and iso-C15 : 1 G as dominant fatty acids, and the primary respiratory quinone was identified as MK-6. The major polar lipids comprised phosphatidylethanolamine, one unidentified glycolipid, one unidentified phospholipid, two unidentified aminolipids, and four unidentified lipids. Based on phylogenetic, phylogenomic, genome relatedness, phenotypic, and chemotaxonomical data, the two isolates represent a novel species within the genus Mangrovimonas, with the proposed name Mangrovimonas cancribranchiae sp. nov., and the type strain UG2_1T (=KCTC 102158T=DSM 117025T).