- Volume 72, Issue 12, 2023

Bacteria in the genus Arthrobacter have been found in extreme environments, e.g. glaciers, brine and mural paintings. Here, we report the discovery of a novel pink-coloured bacterium, strain QL17T, capable of producing an extracellular water-soluble blue pigment. The bacterium was isolated from the soil of the East Rongbuk Glacier of Mt. Everest, China. 16S rRNA gene sequence analysis showed that strain QL17T was most closely related to the species Arthrobacter bussei KR32 T. However, compared to A.bussei KR32T and the next closest relatives, the new species demonstrates considerable phylogenetic distance at the whole-genome level, with an average nucleotide identity of <85 % and inferred DNA–DNA hybridization of <30 %. Polyphasic taxonomy results support our conclusion that strain QL17T represents a novel species of the genus Arthrobacter . Strain QL17T had the highest tolerance to hydrogen peroxide at 400 mM. Whole-genome sequencing of strain QL17T revealed the presence of numerous cold-adaptation, antioxidation and UV resistance-associated genes, which are related to adaptation to the extreme environment of Mt. Everest. Results of this study characterized a novel psychrotolerant Arthrobacter species, for which the name Arthrobacter antioxidans sp. nov. is proposed. The type strain is QL17T (GDMCC 1.2948T=JCM 35246T).

An actinobacterium strain PLK6-54T was isolated from Lankwai peat swamp forest soil collected from Yala province, Thailand. Strain PLK6-54T exhibited morphological and chemotaxonomic properties described for the genus Streptomyces . It formed a spiral spore chain directly on aerial mycelium. Growth was observed between 20 and 40 °C and at pH 5–8. The maximum NaCl for growth was 2 % (w/v). ll-Diaminopimelic acid, arabinose and ribose were detected in the whole-cell hydrolysate. Diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositolmannoside were detected as the phospholipids. The major menaquinones were MK-10(H2) and MK-9(H6). The major cellular fatty acids were iso-C16 : 0, anteiso-C15 : 0 and iso-C14 : 0. 16S rRNA gene sequence data supported the assignment of strain PLK6-54T to the genus Streptomyces and showed that Streptomyces rubidus NBRC 102073T (99.0 %) was the closest relative. Moreover, the average nucleotide identity-blast (85.5 %) and digital DNA–DNA hybridization (30.7 %) values reported between strain PLK6-54T and its closest neighbour were below the threshold values for delineation of a novel species. Strain PLK6-54T could be distinguished from related validly described Streptomyces species by several phenotypic properties. The combination of genotypic and phenotypic data indicated that strain PLK6-54T is representative of a novel species of the genus Streptomyces . The name Streptomyces acidipaludis sp. nov. is proposed for strain PLK6-54T. The type strain is PLK6-54T (=TBRC 11250T=NBRC 114297T).

The name Micromonospora endophytica has been used for three different organisms. The first organism with this name is the species represented by strain DCWR9-8-2T, a species published in 2015 but whose name was never validated. In 2019 the type species of the genus Jishengella was reclassified into the genus Micromonospora , while maintaining its original epithet, thus establishing the second group of organisms known as M. endophytica , but the first for which the name was validated. Additionally, in 2018 the reclassification of the genus Verrucosispora into the genus Micromonospora was proposed, but a new epithet has not been specified for the species named Verrucosispora endophytica , which remains an orphaned species. Therefore, it is necessary to propose new names that can unequivocally identify these taxa. We have analysed the taxonomic position of the strains, comparing them with the species with valid published names of the genus Micromonospora . We here propose Micromonospora thawaii sp. nov. for the species represented by strain DCWR9-8-2T, and Micromonospora grosourdyae nom. nov. and Micromonospora sonchi comb. nov. for the two orphaned species of Verrucosispora , V. endophytica and Verrucosispora sonchi , respectively. Genomic analysis also showed that M. trujilloniae is a later heterotypic synonym of M. andamanensis .

A Gram-stain-positive, aerobic bacterium, designated GW1C4-4T, was isolated from the seawater sample from the tidal zone of Guanyinshan Coast, Xiamen, Fujian Province, PR China. The strain was reddish-orange, rod-shaped and non-motile. Cells of strain GW1C4-4T were oxidase-negative and catalase-positive. The strain could grow at 10–42 °C (optimum, 32–35 °C), pH 5–9 (optimum, pH 6) and with 0–10 % NaCl (w/v; optimum, 1 %). Phylogenetic analysis based on the 16S rRNA sequences indicated that strain GW1C4-4T belonged to the genus Gordonia , having the highest similarity to Gordonia mangrovi HNM0687T (98.5 %), followed by Gordonia bronchialis DSM 43247T (98.4 %). The G+C DNA content was 66.5 mol %. Average nucleotide identity and digital DNA–DNA hybridization values between strain GW1C4-4T and G. mangrovi HNM0687T were 85.8 and 30.0 %, respectively. The principal fatty acids of strain GW1C4-4T were C16 : 0, C18 : 0 10-methyl (TBSA) and summed feature 3 (C16 : 1  ω7c/C16 : 1  ω6c). MK-9 (H2) was the sole respiratory quinone. The polar lipids included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unidentified lipid. Based on its phylogenetic, phenotypic, chemotaxonomic and genomic characteristics, it is proposed that strain GW1C4-4T represents a novel species within the genus Gordonia , for which the name Gordonia tangerina sp. nov. is proposed. The type strain is GW1C4-4T (=MCCC 1A18727T=KCTC 49729T).

Four Gram-stain-positive, facultatively anaerobic, non-motile, non-spore-forming and rod-shaped bacteria (lx-72T, lx-45, ZJ784T and ZJ955) were isolated from the respiratory tract or faeces of marmot (Marmota himalayana) from the Qinghai–Tibet Plateau in China. Analysis of the 16S rRNA gene sequences showed that all strains belong to the genus Canibacter and are more related to Canibacter oris CCUG 64069T (95.1–97.4 % similarity) than to the genus Leucobacter . Both strain pairs grew well at pH 6–9 and 15–42°C, and ZJ784T/ZJ955 could tolerate slightly higher NaCl (0.5–4.5 %, w/v) than lx-72T/lx-45(0.5–3.5 %). Based on whole-genome sequences, the average nucleotide identity and digital DNA–DNA hybridization values between our four isolates and their closest relative were below the species delineation thresholds of 70 % and 95–96 %. The common major fatty acids (>10 %) of our four strains were anteiso-C15 : 0 and anteiso-C17 : 0. For both new type strains, MK-8(H4) and MK-9(H4) were the major isoprenoid quinones, and diphosphatidylglycerol and phosphatidylglycerol were the main polar lipids. The genomic DNA G+C content of all strains was 53.9 mol%. Based on results from the genomic comparison, phylogenetic analysis, and physiological and biochemical characteristics, the four isolates represent two novel species in the genus Canibacter , for which the names Canibacter zhuwentaonis sp. nov. (type strain lx-72T=KCTC 49658T=GDMCC 1.2569T) and Canibacter zhoujuaniae sp. nov. (type strain ZJ784T=KCTC 49507T=GDMCC 1.1997T) are proposed.

Two novel Gram-stain-positive, non-motile and non-spore-forming bacterial strains, designated J2M5T and J1M15T, were isolated from the gastrointestinal tract of a lake prawn Palaemon paucidens. Strain J2M5T was an obligately aerobic bacterium that formed milky-coloured colonies and showed a rod–coccus cell cycle, while strain J1M15T was a facultatively aerobic bacterium that formed orangish-yellow-coloured colonies and showed rod-shaped cells. Strains J2M5T and J1M15T showed the highest 16S rRNA gene sequence similarity to Nocardioides ganghwensis JC2055T (98.63 %) and Tessaracoccus flavescens SST-39T (98.08 %), respectively. The whole-genome sequence of strain J2M5T was 4.52 Mbp in size and the genomic G+C content directly calculated from the genome sequence of strain J2M5T was 72.5 mol%. The whole-genome sequence of strain J1M15T was 3.20 Mbp in size and the genomic G+C content directly calculated from the genome sequence of strain J1M15T was 69.6mol %. Strains J2M5T and J1M15T showed high OrthoANI similarity to N. ganghwensis JC2055T (83.6 %) and T. flavescens (77.2 %), respectively. We analysed the genome sequences of strains J2M5T and J1M15T in terms of carbohydrate-active enzymes, antibiotic resistance genes and virulence factor genes. Strains J2M5T and J1M15T contained MK-8 (H4) and MK-9 (H4) as the predominant respiratory quinones, respectively. The major polar lipids of both strains were phosphatidylglycerol and diphosphatidylglycerol. Additionally, strain J2M5T possessed phosphatidylcholine, phosphatidylserine and phosphatidylethanolamine. The cellular sugar components of strain J2M5T were ribose, mannose, glucose and galactose, and its cellular amino acid components were l-alanine and l-lysine. The cellular sugar components of strain J1M15T were rhamnose, ribose, mannose and glucose, and its cellular amino acid component was l-alanine. The major cellular fatty acids of strains J2M5T and J1M15T were iso-C16 : 0 and anteiso-C15 : 0, respectively. The multiple taxonomic analyses indicated that strains J2M5T and J1M15T represent novel species of the genus Nocardioides and Tessaracoccus , respectively. We propose the names Nocardioides palaemonis sp. nov. and Tessaracoccus palaemonis sp. nov. for strain J2M5T (=KCTC 49461T=CCUG 74767T) and strain J1M15T (=KCTC 49462T=CCUG 74766T), respectively.

A Gram-negative, non-motile, aerobic bacterium, named 02-257T, was isolated from Antarctic soil. The cells are surrounded by relatively thin capsules and were catalase-positive and oxidase-negative cocci. Growth of strain 02-257T was observed at 4–35 °C (optimum, 28–30 °C), pH 6.0–8.0 (optimum, pH 6.0) and with 0–1.5% NaCl (optimum, 0 %). Strain 02–257 showed the highest 16S rRNA gene sequence similarity to Paraconexibacter algicola Seoho-28T (95.06 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 02-257T is a member of a novel species belonging to the clade formed by members of the genus Paraconexibacter in the family Paraconexibacteraceae . The DNA G+C content was 72.9 mol%. Strain 02-257T contained C16 : 0-iso (23.0 %), C18  :  1 ω9c (13.8 %), C16 : 0 (12.5 %) and C17 : 1 ω9c-iso (10.8 %) as major cellular fatty acids and menaquinone MK-7(H4) was detected as the only isoprenoid quinone. Diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositole mannoside, phosphatidylinositole dimannoside, unidentified phosphoglycolipid, unidentified aminophospholipid, two unidentified phospholipids, three unidentified aminolipids and six unidentified lipids were the major polar lipids. meso-Diaminopimelic acids were the diagnostic diamino acids in the cell-wall peptidoglycan. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain 02-257T is considered to represent a novel species of the genus Paraconexibacter , for which the name Paraconexibacter antarcticus sp. nov. is proposed. The type strain is 02-257T (=CCTCC AB 2021030T=KCTC 49619T).

A Gram-stain-positive, irregular short-rod and non-motile bacterium, designated strain ABSL32-1T, was isolated from a soil sample collected from the Suphan Buri municipal solid waste disposal area. According to the results of a polyphasic taxonomic study, a novel species belonging to the genus Paeniglutamicibacter was described. Strain ABSL32-1T grew optimally at 20–25 °C and at pH 6.0–8.0 in the presence of 1 % (w/v) NaCl. The whole-cell sugars were ribose, mannose and glucose. The peptidoglycan structure contained A4α peptidoglycan (Lys–Glu; A11.54). The polar lipids contained digalactosyldiacylglycerol, diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids and two unidentified lipids. The major menaquinones were MK-9 and MK-10. The major cellular fatty acid was anteiso-C15 : 0 (70.1 %). Based on 16S rRNA gene sequence analysis, strain ABSL32-1T showed the highest similarity to Paeniglutamicibacter sulfureus DSM 20167T (99.5 %), followed by Paeniglutamicibacter antarcticus SPC26T (99.0 %) and Paeniglutamicibacter psychrophenolicus AG31T (98.8 %). The genome of strain ABSL32-1T is 4.4 Mbp with a DNA G+C content of 66.0 mol%. The average nucleotide identity values between strain ABSL32-1T and the type strains P. sulfureus DSM20167T, P. antarcticus SPC26T and P. psychrophenolicus AG31T were 86.6, 74.7 and 83.6 %, respectively. On the basis of phenotypic, chemotaxonomic and genotypic properties, strain ABSL32-1T is proposed to represent a novel species to be named Paeniglutamicibacter quisquiliarum sp. nov. The type strain is ABSL32-1T (=TBRC 14976T=NBRC 115252T).

A novel Gram-stain-positive, endophytic actinobacterium, designated strain HDS5T, was isolated from leaves of Eucommia ulmoides Oliv. collected from Changde City, Hunan Province, PR China. Strain HDS5T produced yellowish oil green substrate mycelia on Gause’s synthetic medium, which also carried yellowish oil green aerial hyphae, fragmenting into rod-shaped elements with smooth surfaces. Strain HDS5T grew at pH 5.0–11.0 (optimum, pH 7), at 20–40 °C (optimum, 28 °C) and in the presence of 0–8.0% NaCl (w/v; optimum, 0–1.0 %). Whole-cell hydrolysates contained meso-diaminopimelic acid as the diagnostic amino acid and no diagnostic sugars. The predominant fatty acids were iso-C16:0 and C18 : 1 ω9c. The menaquinones were MK-10(H2), MK-10(H4) and MK-10(H6). Strain HDS5T showed high 16S rRNA gene sequence similarity to Nocardiopsis prasina DSM 43845T (99.72 %), Nocardiopsis ganjiahuensis DSM 45031T (99.31 %), Nocardiopsis exhalans JCM 11759T (99.17 %), Nocardiopsis alba DSM 43377T (99.11 %), Nocardiopsis metallicus KBS6T (99.11 %), Nocardiopsis valliformis DSM 45023T (99.04 %), Nocardiopsis listeri NBRC 13360T (98.97 %), Nocardiopsis lucentensis DSM 44048T (98.83 %), Nocardiopsis terrae YIM 90022T (98.83 %) and <98.7 % similarities to other type strains. Phylogenetic analysis of 16S rRNA gene sequences and whole-genome sequences showed that strain HDS5T was closely related to N. prasina DSM 43845T. However, the average nucleotide identity based on blast and digital DNA–DNA hybridization values between them were determined to be 90.1 and 40.9 %, respectively, below the threshold of 95–96 and 70 % for the delineation of prokaryotic genomic species, suggesting that strain HDS5T represents a novel Nocardiopsis species. Furthermore, the morphological and physio-biochemical characteristics were sufficient to distinguish strain HDS5T from N. prasina DSM 43845T. Consequently, based on phenotypic and genotypic characteristics, strain HDS5T represents a new Nocardiopsis species, for which the name Nocardiopsis eucommiae sp. nov. is proposed. The type strain is HDS5T (=MCCC 1K06172T=JCM 34707T).

A Gram-stain positive, facultatively anaerobic, motile rod-shaped strain, BY-33T, was isolated from a soil sample obtained from the Kubuqi Desert, PR China. Phylogenetic analysis based on 16S rRNA gene sequence similarity revealed that strain BY-33T was most closely related to the genus Actinotalea , including Actinotalea ferrariae CF5-4T (98.2 % similarity), ‘Actinotalea subterranea’ HO-Ch2T (98.0 %), Actinotalea solisilvae THG-T121T (97.6 %), ‘Actinotalea bogoriensis’ 69B4T (97.5 %), Actinotalea fermentans MT (97.3 %) and ‘Actinotalea carbonis’ T26T (97.0 %). The strain grew at 0‒37 °C (optimum, 28–30 °C) and pH 6.0–11.0 (optimum, pH 9.0–10.0) and with 0‒8.0 % (w/v) NaCl (optimum, 3.0%) on tryptic soy agar. It had catalase activity, but no oxidase activity. The polar lipids of strain BY-33T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannosides. The major respiratory quinone of strain BY-33T was MK-10 (H4). Its major fatty acids were anteiso-C15 : 0, anteiso-C15 : 1 A and C16 : 0. The genomic DNA G+C content of strain BY-33T was 73.0 mol% based on total genome calculations. The average nucleotide identity scores between the genomic sequences of strain BY-33T and the other species of the genus Actinotalea were found to be low (ANIm <85.0 %, ANIb <77.0 % and OrthoANIu <78.0 %). Furthermore, the digital DNA–DNA hybridization and average amino acid identity values between strain BY-33T and the closely related species ranged from 20.5 to 21.0% and from 62.2 to 72.2 %, respectively. Based on the results of phylogenetic, phenotypic, genotypic and chemotaxonomic analyses, it is concluded that strain BY-33T represents a novel species within the genus Actinotalea , for which the name Actinotalea soli sp. nov. is proposed. The type strain is BY-33T (=CGMCC 1.17460T=KCTC 49362T).

A polyphasic approach was used to describe strain RB6PN25T, an actinobacterium isolated from peat swamp forest soil in Rayong Province, Thailand. The strain was a Gram-stain-positive and filamentous bacterium that contained ll -diaminopimelic acid, mannose and ribose in whole-cell hydrolysates. MK-9(H8) was the major menaquinone. The major fatty acids were iso-C16 : 0, anteiso-C15 : 0 and iso-C15 : 0. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, two unidentified glycophospholipids, two unidentified aminolipids and an unidentified phospholipid. The 16S rRNA gene sequences analysis indicated that it was most closely related to Streptomyces rubrisoli DSM 42083T (97.6 %) and Streptomyces palmae TBRC 1999T (97.4 %). Strain RB6PN25T exhibited low average nucleotide identity and digital DNA–DNA hybridization values with S. rubrisoli DSM 42083T (78.6 %, 23.2 %) and S. palmae TBRC 1999T (76.0 %, 22.6 %). The DNA G+C content of strain RB6PN25T was 69.9%. The results of phenotypic, chemotaxonomic, genotypic and phylogenetic analyses reveal that strain RB6PN25T represents a novel species of the genus Streptomyces , for which the name Streptomyces humicola sp. nov. is proposed. The type strain is RB6PN25T (=TBRC 14819T=NBRC 115204T).

A filamentous cell-shaped halophilic archaeon (strain AD-1T) was isolated from Aiding Salt Lake, PR China. Its colonies on HCM7 agar plates were pinkish white, 1–4 mm (diameter), elevated and round. The optimum conditions for growth were observed at 42 °C, 4.3 M NaCl, 0.01 M MgCl2 and pH 7. Strain AD-1T could hydrolyse Tween 60, Tween 80, starch and gelatin. Phylogenetic analysis based on 16S rRNA gene, rpoB′ and the concatenated 484 single-copy orthologous proteins revealed that strain AD-1T formed a clade with Halocatena pleomorpha SPP-AMP-1T. The average nucleotide identity and in silico DNA–DNA hybridization values between strain AD-1T and Halocatena pleomorpha SPP-AMP-1T were both below the species delineation thresholds (95~96 and 70 %, respectively). The major phospholipids of strain AD-1T were phosphatidic acid, phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester, while the major glycolipids were sulphated galactosyl mannosyl glucosyl diether, galactosyl mannosyl glucosyl diether and glucosyl mannosyl glucosyl diether. The phenotypic, phylogenetic and genome-based analyses suggested that strain AD-1T (=CGMCC 1.13724T=JCM 32960T) represents a novel species, for which the name Halocatena salina sp. nov. is proposed.

A Gram-stain-negative, non-motile and rod-shaped bacterium, designated as strain W52T, was isolated from deep seawater of the Mariana Trench and characterized phylogenetically and phenotypically. The strain could grow at 10–47 °C (optimum 32 °C), at pH 5.0–8.0 (optimum 6.0) and with 0–9% NaCl (optimum 3 %, w/v). The results of phylogenetic analysis based on 16S rRNA gene sequences indicated that W52T was related to members of the genus Muricauda and shared the highest identity with Muricauda oceani 501str8T (99.0 %), followed by Muricauda aquimarina JCM 11811T, Muricauda ruestringensis DSM 13258T, Muricauda oceanensis 40DY170T, Muricauda beolgyonensis KCTC 23501T and Muricauda zhangzhouensis 12C25T with 97.0–98.8 % sequence similarity. 16S rRNA gene sequence identities between W52T and other members of the genus Muricauda were below 97.0 %. The major respiratory quinone was MK-6. The polar lipids were phosphatidylethanolamine (PE), one unidentified aminolipid and three unidentified lipids. The strain had iso-C15 : 0, iso-C17 : 0 3-OH and iso-C15 : 1G as the major fatty acids. The G+C content of the genomic DNA was 41.7 %. The combined genotypic and phenotypic data indicated that strain W52T represents a novel species of the genus Muricauda , for which the name Muricauda abyssi sp. nov. is proposed, with the type strain W52T (=MCCC 1K05111T= KCTC 82315T).

Thousands of lakes harbouring different characteristics (pH, salinity, temperature) are located on the Tibetan Plateau, and the mining of microbial resources inhabited in these lakes has great value. Two Gram-stain-negative, aerobic, rod-shaped, non-motile strains (LQ15WT and AIY15WT) were isolated from freshwater lakes on the Tibetan Plateau. Comparisons based on the 16S rRNA gene sequences showed that both strains LQ15WT and AIY15WT share 16S rRNA gene sequence similarities 98.4 % with Aquiflexum aquatile Z0201T, but only about 95.0 % with Aquiflexum balticum DSM 16537T. The 16S rRNA gene sequence similarity between strains LQ15WT and AIY15WT was 98.9 %. The phylogenetic tree reconstructed based on 16S rRNA gene sequences also showed that strains LQ15WT and AIY15WT take A. aquatile Z0201T as their closest neighbour and these three strains form a tight cluster. In the phylogenomic tree, the genus Aquiflexum was splited into two clusters by Mariniradius saccharolyticus . Strains LQ15WT, AIY15WT and A. aquatile Z0201T still formed a close cluster, and A. balticum DSM 16537T and Aquiflexum lacus CUG 91378T formed another cluster. The calculated OrthoANIu, average amino acid identity and digital DNA–DNA hybridization values among strains LQ15WT, AIY15WT, A. aquatile Z0201T, A. balticum DSM 16537T and A. lacus CUG 91378T were less than 91.0, 92.9 and 42.1 %, respectively. The major respiratory quinones of both strains LQ15WT and AIY15WT were MK-7 (32 %) and MK-8 (68 %), and their major fatty acids were iso-C15 : 0, C18 : 1  ω9c, summed feature 3 and summed feature 9. The predominant polar lipids of both strains were phosphatidylethanolamine, unidentified aminophospholipids, unidentified phospholipids and lipids. Strain AIY15WT also contained phosphatidylglycerol and unidentified glycolipid. Considering the distinct phylogenetic relationships and chemotaxonomic characteristics between strains A. aquatile Z0201T and A. balticum DSM 16537T, it is proposed to reclassify A. aquatile into a novel genus Cognataquiflexum gen. nov. as Cognataquiflexum aquatile comb. nov., and strains LQ15WT and AIY15WT should represent two independent novel species of the genus Cognataquiflexum, for which the names Cognataquiflexum nitidum sp. nov. (type strain: LQ15WT=CICC 24711T=JCM 34222T) and Cognataquiflexum rubidum sp. nov. (type strain: AIY15WT=CICC 24708T=JCM 34612T) are proposed.

Strains RB4R14T and RT5R15T, two Gram-stain-negative, aerobic, rod-shaped, non-motile bacteria, were isolated from ice and cryoconite of Renlongba glacier, respectively, on the Tibetan Plateau, PR China. The results of phylogenetic analysis based on 16S rRNA genes indicated that strains RB4R14T and RT5R15T belonged to the genus Mucilaginibacter with the highest similarities to Mucilaginibacter rigui WPCB133T (98.78 %) and Mucilaginibacter xinganensis BJC16-A31T (97.64 %), respectively. The genomic DNA G+C contents of strains RB4R14T and RT5R15T were 42.8 and 43.1 mol%, respectively. The digital DNA–DNA hybridization values between strains RB4R14T, RT5R15T and their close relatives were below 31.9 and 17.4 %, respectively. The average nucleotide identity values between the two novel strains and their close relatives were 79.5–82.0 and 77.9–79.3 % respectively, indicating the novelty of the two isolates at a species level. The two novel strains contained MK-7 as the major menaquinone, and summed feature 3 (comprising C16 : 1  ω7c and/or C16 : 1  ω6c), iso-C15 : 0 and iso-C17 : 0-3OH as the major fatty acids. The major polar lipid of the two novel strains were phosphatidylethanolamine. Based on phenotypic, chemotaxonomic and phylogenetic results, we propose two novel species, Mucilaginibacter aurantiaciroseus sp. nov. (RB4R14T=CGMCC 1.11911T=NBRC 114020T) and Mucilaginibacter flavidus sp. nov. (RT5R15T=CGMCC 1.23117T=NBRC 113930T).

Members of the genus Paenibacillus are well known for their metabolic versatility and great application potential in plant growth promotion. Three novel bacterial strains, designated N4T, JC52T and PR3T, were isolated from rhizosphere soils and characterized by using a polyphasic taxonomic approach. The 16S rRNA gene sequence phylogenetic and phylogenomic analysis revealed that the three strains belonged to the genus Paenibacillus and formed three independent branches distinct from all reference strains. The results of DNA–DNA hybridization (DDH) and average nucleotide identity (ANI) analyses between the three strains and their relatives further demonstrated that the three strains represented different novel genospecies. Strain N4T exhibited the highest similarity, ANI and digital DDH values with Paenibacillus assamensis DSM 18201T (99.0/87.5/33.9 %) and Paenibacillus insulae DS80T (97.2/–/18.2±1.2 %). Values for JC52T with Paenibacillus validus NBRC 15382T were 96.9, 73.3 and 19.6 %, and with Paenibacillus rigui JCM 16352T were 96.1, 72.1 and 19.3 %. Values for PR3T with Paenibacillus ginsengiterrae DCY89T were 98.2, – and 31.8±1.5 %, with Paenibacillus cellulosilyticus ASM318225v1T were 97.8, 83.3 and 26.7 %, and with Paenibacillus kobensis NBRC 15729T were 97.6, 75.7 and 20.4 %. Cells of the three novel bacterial strains were Gram-positive, spore-forming, motile and rod-shaped. The novel species contained anteiso-C15 : 0 and MK-7 as the predominant fatty acid and menaquinone, respectively. The novel strains have numerous similar known clusters of non-ribosomal peptide synthetases, siderophores, lanthipeptide, lassopeptide-like bacillibactin, paeninodin and polyketide-like chejuenolide A/B lankacidin C. Based on the distinct morphological, physiological, chemotaxonomic and phylogenetic differences from their closest phylogenetic neighbours, we propose that strains N4T, JC52T and PR3T represent novel species of the genus Paenibacillus , with the names Paenibacillus agilis sp. nov. (=KACC 19717T=JCM 32775T), Paenibacillus cremeus sp. nov. (=KACC 21221T=NBRC 113867T) and Paenibacillus terricola sp. nov. (=KACC 21455T=NBRC 114385T), respectively.

Two Gram-stain-positive bacterial strains, designated 213-9(3)T and 30-1(2)T, were isolated from traditional Chinese pickle, and were characterized using a polyphasic taxonomic approach. Results of 16S rRNA gene sequence analysis indicated that strain 213-9(3)T was most closely related to Levilactobacillus paucivorans TMW 1.1424T, Levilactobacillus huananensis 151-2BT and Levilactobacillus lindianensis 220-4T, having 99.7–99.9 % 16S rRNA gene sequence similarities; strain 30-1(2)T was most closely related to Lapidilactobacillus achengensis 247-4T, with 99.4 % 16S rRNA gene sequence similarity. Strain 213-9(3)T shared the highest pheS (93.9 %), rpoA (99.3 %) and concatenated pheS and rpoA (97.5 %) sequence similarities to L. paucivorans TMW 1.1424T. Strain 30-1(2)T had the highest pheS (82.4 %), rpoA (95.5 %) and concatenated pheS and rpoA (91.2 %) sequence similarities to L. achengensis 247-4T. The phylogenetic relationships based on concatenated pheS and rpoA sequences and whole genome sequences were identical to those based on 16S rRNA gene sequences. Strain 213-9(3)T exhibited the highest average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values (92.7 and 48.8 %, respectively) to L. paucivorans DSM 22467T. Strain 30-1(2)T had the highest ANI (84.4 %) and dDDH (32.8 %) values with L. achengensis 247-4T. Acid production from d-galactose, d-glucose, d-mannose, N-acetyl-β-glucosaminidase, arbutin, salicin, cellobiose, maltose, gentiobiose, d-tagatose and gluconate, hydrolysis of aesculin, and activity of cystine arylamidase could differentiate strain 213-9(3)T from L. paucivorans DSM 22467T. Acid production from l-arabinose, d-ribose, d-xylose and d-galactose, and activity of alkaline phosphatase, esterase (C4), α-mannosidase and α-fucosidase could differentiate strain 30-1(2)T from L. achengensis 247-4T. Based upon the data obtained in the present study, two novel species, Levilactobacillus humaensis sp. nov. and Lapidilactobacillus luobeiensis sp. nov., are proposed and the type strains are 213-9(3)T (=CCM 9241T=CCTCC AB 2022115T=JCM 35554T) and 30-1(2)T (=CCM 9240T=CCTCC AB 2022114T=JCM 35553T), respectively.