Polyphasic Analysis Research Articles

New members of the family Eggerthellaceae isolated from Marmota himalayana: Xiamenia xianingshaonis gen. nov., sp. nov., from intestinal contents, and Berryella wangjianweii sp. nov., from trachea.

Four strictly anaerobic, Gram-stain-positive, urease-, oxidase- and catalase-negative, rod-shaped strains (zg-886T/zg-887 and zg-1050T/zg-1084) were isolated from Marmota himalayana. Comparison analysis of 16S rRNA genes showed that the two strain pairs belong to the family Eggerthellaceae : zg-1050T and zg-1084 were most closely related to Berryella intestinalis 68-1-3T (97.2 %), while zg-886T/zg-887 had the highest similarity to Slackia piriformis YIT 12062T (91.6 %), followed by Paraeggerthella hongkongensis DSM 16106T (91.4 %) and Gordonibacter urolithinfaciens DSM 27213T (91.4 %). Phylogenetic analyses based on 16S rRNA genes and genomes showed that the two strain pairs represent two different lineages within the family Eggerthellaceae . The genomic G+C contents of strains zg-886T and zg-1050T were 63.0 and 66.3 mol%, respectively. The values of digital DNA–DNA hybridization, average nucleotide identity, average amino acid identity and the percentage of conserved proteins between the two new type strains and members of the family Eggerthellaceae were lower than the respective thresholds for delineation of a species or genus. In contrast to the absence of any known quinones in strain zg-1050T, strain zg-886T contained MK-6 (42.5 %), MMK-6 (25.0 %) and DMMK-6 (32.5 %). The four strains grew optimally at pH 7.0, 37 ºC and 0.5 % NaCl (w/v). According to these polyphasic analyses, two new members within the family Eggerthellaceae are proposed, Xiamenia xianingshaonis gen. nov., sp. nov. (zg-886T=JCM 34097T=GDMCC 1.1710T) and Berryella wangjianweii sp. nov. (zg-1050T=GDMCC 1.2426T=JCM 34748T).

Aquibacillus saliphilus sp. nov., a moderately halophilic bacterium isolated from a grey saltern.

A novel moderately halophilic bacterium, designated strain KHM2T, was isolated from the sediment of a grey solar saltern located on Sinui Island, Shinan, Republic of Korea. Cells were rod-shaped, endospore-forming, Gram-stain-positive, motile and facultative anaerobic. Strain KHM2T performed anaerobic respiration using nitrates and did not produce glucose acids, indicating the absence of fermentation. Strain KHM2T grew at 10-45 °C (optimum, 37 °C), pH 6.0-10.0 (optimum, pH 8.0) and with 1.0-20.0 % (w/v) NaCl (optimum, 10.0%). Based on 16S rRNA gene sequence similarity and chemotaxonomic properties, strain KHM2T was assigned to the genus Aquibacillus, with high 16S rRNA gene sequence similarity to Aquibacillus halophilus B6BT (98.2%) and less than 96.8 % similarity to the other recognized members of the genus Aquibacillus. The polar lipid profile consisted of diphosphatidylglycerol (DPG), phosphatidylglycerol (PG) and one unidentified phospholipid (PL). Major fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0. The average nucleotide identity and digital DNA-DNA hybridization values of strain KHM2T with A. halophilus B6BT were 77.6 and 22.0 %, respectively. Based on the results of polyphasic analysis, strain KHM2T is proposed to represent a bacterial species within the genus Aquibacillus with the name Aquibacillus saliphilus sp. nov. The type strain is KHM2T (=KACC 19068T=NBRC 112577T).

Microvirga terrestris sp. nov., and Microvirga arvi sp. nov., isolated from soil in South Korea.

Two novel Gram-stain-negative, aerobic, rod shaped bacterial strains BT290T and BT689T were isolated from soil collected in South Korea. Colony morphologies of both strains were circular and convex while the colors of BT290T and BT689T were light-pink and white, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that BT290T and BT689T belong to a distinct lineage within the genus Microvirga (family Methylobacteriaceae, order Rhizobiales, class Alphaproteobacteria, phylum Proteobacteria, kingdom Bacteria). The 16S rR NA gene sequence similarity between two strains was 97.9%. Both strains had the similar quinone system, with ubiquinone 10 (Q-10) as the major respiratory quinone. The major polar lipids of strains BT290T and BT689T were phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), phosphatidylcholine (PC), and phosphatidylglycerol (PG). The major cellular fatty acids of strain BT290T were C18:1 ω7c (58.2%) and C16:0 (17.7%), while those of strain BT689T were C18:1 ω7c (61.8%) and C16:0 (10.8%). On the bases of polyphasic analysis (phylogenetic, chemotaxonomic, and biochemical), strains BT290T and BT689T can be suggested as novel bacterial species within the genus Microvirga and the proposed names are Microvirga terrestris and Microvirga arvi, respectively. The type strain of Microvirga terrestris is BT290T (= KCTC 72367T = NBRC 114844T) and the type strain of Microvirga arvi is BT689T (= KACC 22016T = NBRC 114858T), respectively.

Orrella daihaiensis sp. nov., a bacterium isolated from Daihai Lake in Inner Mongolia.

A novel aerobic, Gram-staining-negative, non-motile, short-rod-shaped strain, designated f23T, was obtained from Daihai Lake, Inner Mongolia, Republic of China. 16S rRNA gene sequences analysis showed that f23T belongs to the genus Orrella and is most closely related to Orrella marina H-Z20T with 98.35% sequence similarity. The strain was oxidase positive, catalase positive and had well growth at pH 6.5-8.5, at temperature 28-40°C and at 0-4.5% (w/v) NaCl. Colonies incubated at 37°C on marine 2216 agar for 3days were white, smooth, transparent, circular and less than 1.0mm in diameter. The total genome size of f23T was 2,803,849bp with a G + C content of 52.79%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain f23T and O. marina H-Z20T were 69.62% and 20.5%, which both below the species delineation threshold. Chemotaxonomic analysis showed that C16:0, cyclo-C17:0, C18:0, Sum Feature 3 (C16:1ω7c and/or C16:1ω6c) and Sum Feature 8 (C18:1ω6c and C18:1ω7c) as the major fatty acids, ubiquinone-8 as the major isoprenoid quinone, phosphatidylethanolamine as the major cellular polar lipids. Based on the polyphasic analysis, f23T represents a novel species within the genus Orrella, for which the name Orrella daihaiensis sp. nov. is proposed. The type strain is f23T (= CGMCC 1.18761T = KCTC 82425T).

Hymenobacter translucens sp. nov. and Hymenobacter pini sp. nov. isolated from soil.

Two novel bacterial strains BT175T and BT728T were isolated from soil collected in the Republic of Korea. Both strains were Gram stain negative, rod shaped, and had circular, convex, and pink-colored colonies. The 16S rRNA gene sequence similarity between the strains BT175T and BT728T was 93.6%, indicating that they represent a distinct species. 16S rRNA sequence analysis indicated that strains BT175T and BT728T belong to a distinct lineage within the genus Hymenobacter (family Hymenobacteraceae, order Cytophagales, class Cytophagia, phylum Bacteroidetes). Strain BT175T was closely related to Hymenobacter persicinus 1-3-3-3T (97.2%, 16S rRNA gene similarity), Hymenobacter knuensis 16F7C-2T (96.6%), and Hymenobacter daejeonensis PB105T (96.1%). Strain BT728T was closely related to Hymenobacter rigui KCTC 12533T (98.4%), Hymenobacter metallilatus 9PBR-2T (97.6%), and Hymenobacter perfusus LMG26000T (97.4%). Strain BT175T and BT728T were found to have the MK-7 as the major respiratory quinone. The DNA G + C content of strain BT175T was 61.6mol% and BT728T was 59.6mol%, respectively. Characterization based on polyphasic analysis indicated that strains BT175T and BT728T represent novel species of the genus Hymenobacter and the names Hymenobacter translucens sp. nov. and Hymenobacter pini sp. nov. are proposed. The type strain of Hymenobacter translucens is BT175T (= KCTC 72330T = NBRC 115441T) and Hymenobacter pini is BT728T (= KACC 22629T = NBRC 115444T).

Thauera sedimentorum sp. nov., Isolated from Coastal Sediment.

A Gram-negative, strictly aerobic, rod-shaped, non-spore-forming bacterium, designated CAU 1555T, was isolated from a sediment sample collected on Jeju Island, Republic of Korea. Growth of the isolate was observed at 20-37°C (optimum at 30°C) and pH 5.5-10.0 (optimum at 8.0). Phylogenetic analysis based on the result of 16S rRNA gene sequences revealed that strain CAU 1555T belonged to the genus Thauera and was closely related to Thauera hydrothermalis GD-2T (98.4% sequence similarity), Thauera lacus D20T (96.6%), and Thauera linaloolentis 47LolT (95.5%). Strain CAU 1555T possessed phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid, and one aminophospholipid as the major polar lipids; Q-8 as the predominant respiratory quinone; and C16:0, summed feature 3 (comprising C16:1ω6c and/or C16:1ω7c), and summed feature 8 (comprising C18:1 ω7c/ C18:1 ω6c) as the major fatty acids. The average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridization (dDDH) values between the new isolate and T. hydrothermalis GD-2T were 84.5%, 86.4%, and 28.0%, respectively. Whole-genome sequencing of strain CAU 1555T revealed 3,955,289bp with a DNA G + C content of 68.0mol%. Based on the results of its polyphasic properties and genomic analysis, the isolate represents a novel species within the genus Thauera, for which the name Thauera sedimentorum sp. nov. is proposed, with CAU 1555T (= KCTC 72546T = MCCC 1K04065T) as the type strain.

Marinifilum caeruleilacunae sp. nov., isolated from Yongle Blue Hole in the South China Sea.

A Gram-stain-negative, non-motile, facultatively anaerobic and non-flagellated marine bacterium, designated JC070T was isolated from the Yongle Blue Hole in the South China Sea. The temperature, pH and NaCl ranges for growth of strain JC070T were 4-37 °C (optimum, 16 °C), pH 6.0-9.0 (optimum, pH 7.0) and 1.0 -6.0% (w/v; optimum, 3.0%). The predominant isoprenoid quinone of strain JC070T was identified as menaquinone-7. The dominant fatty acids (>10%) were iso-C15:0 (59.6%) and iso-C17:0 3-OH (17.2%). The major polar lipids were aminophospholipid, aminolipid, two unknown phospholipids and two unidentified lipids. The genomic DNA G+C content was determined to be 37.0 mol%. Based on the results of polyphasic analysis, a new species, named Marinifilum caeruleilacunae sp. nov., within the genus Marinifilum was proposed. The type strain is JC070T (= JCM 39045T=MCCC 1K03774T).

Polyphasic Analysis Reveals Potential Petroleum Hydrocarbon Degradation and Biosurfactant Production by Rare Biosphere Thermophilic Bacteria From Deception Island, an Active Antarctic Volcano.

Extreme temperature gradients in polar volcanoes are capable of selecting different types of extremophiles. Deception Island is a marine stratovolcano located in maritime Antarctica. The volcano has pronounced temperature gradients over very short distances, from as high as 100°C in the fumaroles to subzero next to the glaciers. These characteristics make Deception a promising source of a variety of bioproducts for use in different biotechnological areas. In this study, we isolated thermophilic bacteria from sediments in fumaroles at two geothermal sites on Deception Island with temperatures between 50 and 100°C, to evaluate the potential capacity of these bacteria to degrade petroleum hydrocarbons and produce biosurfactants under thermophilic conditions. We isolated 126 thermophilic bacterial strains and identified them molecularly as members of genera Geobacillus, Anoxybacillus, and Brevibacillus (all in phylum Firmicutes). Seventy-six strains grew in a culture medium supplemented with crude oil as the only carbon source, and 30 of them showed particularly good results for oil degradation. Of 50 strains tested for biosurfactant production, 13 showed good results, with an emulsification index of 50% or higher of a petroleum hydrocarbon source (crude oil and diesel), emulsification stability at 100°C, and positive results in drop-collapse, oil spreading, and hemolytic activity tests. Four of these isolates showed great capability of degrade crude oil: FB2_38 (Geobacillus), FB3_54 (Geobacillus), FB4_88 (Anoxybacillus), and WB1_122 (Geobacillus). Genomic analysis of the oil-degrading and biosurfactant-producer strain FB4_88 identified it as Anoxybacillus flavithermus, with a high genetic and functional diversity potential for biotechnological applications. These initial culturomic and genomic data suggest that thermophilic bacteria from this Antarctic volcano have potential applications in the petroleum industry, for bioremediation in extreme environments and for microbial enhanced oil recovery (MEOR) in reservoirs. In addition, recovery of small-subunit rRNA from metagenomes of Deception Island showed that Firmicutes is not among the dominant phyla, indicating that these low-abundance microorganisms may be important for hydrocarbon degradation and biosurfactant production in the Deception Island volcanic sediments.

Pseudemcibacter aquimaris gen. nov., sp. nov., isolated from an aquaculture farm.

A rod-shaped, Gram-stain-negative, aerobic and non-motile bacterium, designated strain Y4T, was isolated from an aquaculture farm in Xiamen, PR China. Strain Y4T had 94.8, 93.3 and 91.8 % 16S rRNA gene sequence similarity to Paremcibacter congregatus ZYLT, Emcibacter nanhaiensis HTCJW17T and Luteithermobacter gelatinilyticus MEBiC09520T, respectively. The genomic DNA G+C content of strain Y4T was 42.7 mol%. The average amino acid identity and percentage of conserved proteins values between strain Y4T and type strains of the family Emcibacteraceae were 57.9-58.6 % and 44.5-47.6 %, respectively. Optimal growth was observed at 28 °C, at pH 7.0 and with 2 % (w/v) NaCl. The novel strain Y4T required Ca2+, K+ and Mg2+ ions in addition to NaCl for growth. The dominant fatty acids of strain Y4T were summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c) and C14 : 0 2-OH. The polar lipid profile contained phosphatidylethanolamine, phosphatidyglycerol, three unidentified aminolipids, four unidentified aminophospholipids and two unidentified lipids. Cells contained exclusively ubiquinone Q-10. On the basis of the polyphasic analysis, strain Y4T (=MCCC 1K06278T=KCTC 82926T) is considered to represent a novel species in a novel genus of the family Emcibacteraceae, for which the name Pseudemcibacter aquimaris gen. nov., sp. nov. is proposed.

Colletotrichum truncatum causing anthracnose disease of Iris lactea in Beijing, China

AbstractIris lactea is a wide ground cover plant of importance throughout courtyards, trees and roads. From May to September in 2020 and 2021, I. lactea planted in Beijing showed white to yellow spots with black conidiomata and could lead blight expanded down from the tip of leaves. In this study, ninety‐six diseased leaves were collected from nineteen regions in Beijing, and a total of fifty‐nine Colletotrichum isolates were obtained from the leaf spots. All isolates were identified as Colletotrichum truncatum by polyphasic analyses, combing morphology and phylogeny of combined the internal transcribed spacer of rDNA region (ITS), actin (act), chalcone synthetase (chs), the genes of glyceraldehyde‐3‐phosphate dehydrogenase (gapdh) and β‐tubulin (tub2). Koch's postulates were confirmed by a pathogenicity test using conidial suspensions (1 × 106 conidia/ml) on fresh leaves of the host, re‐isolation and identification. Until now, this is the first confirmed report of a new anthracnose disease of I. lactea caused by C. truncatum in China.

Oceanospirillum sediminis sp. nov., Isolated From Coastal Sediment in the Yellow Sea.

A novel Gram-negative, motile, aerobic, spiral-shaped bacterium designated D5T, was isolated from a coastal sediment collected in the Yellow Sea. Optimal growth occurred at 30°C, pH 7.0-8.0 and in the presence of 1-3% (w/v) NaCl. Strain D5T contained ubiquinone 8 (Q-8) as the predominant respiratory quinone. The major fatty acids (> 10%) were C16:0, C16:1 ω7c/C16:1 ω6c and C18:1w7c/C18:1w6c. The main polar lipids were phosphatidylglycerol and phosphatidylethanolamine. The draft genome is 5.6Mb in length, and DNA G + C content is 47.2mol%. 16S rRNA gene sequences showed that strain D5T is most closely related to Oceanospirillum beijerinckii NBRC 15445T (97.8%, sequence similarity). However, the digital DNA-DNA hybridization (dDDH) value and average nucleotide identity (ANI) between strain D5T and O. beijerinckii is only 27.8% and 77.1%. Phylogenetic trees based on 16S rRNA gene sequences and whole genomes all indicated that strain D5T formed a separate branch in the genus Oceanospirillum. Combined results of the polyphasic analyses suggested that strain D5T represents a novel species in the genus Oceanospirillum, for which the nameOceanospirillum sediminissp. nov. is proposed. The type strain is D5T (= MCCC 1K06061T = KCTC 62987T).

Reclassification of Enterobacter sp. FY-07 as Kosakonia oryzendophytica FY-07 and Its Potential to Promote Plant Growth

Precise classification of bacteria facilitates prediction of their ecological niche. The genus Enterobacter includes pathogens of plants and animals but also beneficial bacteria that may require reclassification. Here, we propose reclassification of Enterobacter FY-07 (FY-07), a strain that has many plant-growth-promoting traits and produces bacterial cellulose (BC), to the Kosakonia genera. To re-examine the taxonomic position of FY-07, a polyphasic approach including 16S rRNA gene sequence analysis, ATP synthase β subunit (atpD) gene sequence analysis, DNA gyrase (gyrB) gene sequence analysis, initiation translation factor 2 (infB) gene sequence analysis, RNA polymerase β subunit (rpoB) gene sequence analysis, determination of DNA G + C content, average nucleotide identity based on BLAST, in silico DNA–DNA hybridization and analysis of phenotypic features was applied. This polyphasic analysis suggested that Enterobacter sp. FY-07 should be reclassified as Kosakonia oryzendophytica FY-07. In addition, the potential of FY-07 to promote plant growth was also investigated by detecting related traits and the colonization of FY-07 in rice roots.

Photobacterium halophilum sp. nov. and a Salt-Loving Bacterium Isolated from Marine Sediment

A Gram-stain-negative, rod-shaped, and facultatively anaerobic bacterium named strain GJ3T was isolated from coastal sediment of Jeju Island, South Korea. Catalase and oxidase activity were detected in the cell of strain GJ3T, as well as white pigmented colony and motility with polar flagellum. The cell grew optimally at 30 °C, pH 7.0, in the presence of 4% (w/v) sodium chloride. Phylogenetic analysis using the 16S rRNA gene sequence indicated that strain GJ3T was classified to the genus Photobacterium, with high sequence similarity to Photobacterium galatheae S2753T (98.30%), Photobacterium halotolerans MACL01T (97.90%), and Photobacterium panuliri LBS5T (96.55%). Strain GJ3T possessed only ubiquinone-8 (Q-8) as a respiratory quinone and summed feature 8 as the major fatty acid (38.18%). Additionally, the dominant polar lipids phosphatidylglycerol and phosphatidylethanolamine were identified. The complete genome size and G + C content of strain GJ3T was estimated to be 3,603,274 bp in length and 50.70%, respectively. Polyphasic approach and genomic analyses (e.g., ANI and digital DDH) revealed that strain GJ3T (=KCTC 72816T = KMM 6822T) represented a novel species within the genus Photobacterium, and the name Photobacterium halophilum sp. nov., is proposed for this novel bacterium.

Mucisphaera calidilacus gen. nov., sp. nov., a novel planctomycete of the class Phycisphaerae isolated in the shallow sea hydrothermal system of the Lipari Islands

For extending the current collection of axenic cultures of planctomycetes, we describe in this study the isolation and characterisation of strain Pan265T obtained from a red biofilm in the hydrothermal vent system close to the Lipari Islands in the Tyrrhenian Sea, north of Sicily, Italy. The strain forms light pink colonies on solid medium and grows as a viscous colloid in liquid culture, likely as the result of formation of a dense extracellular matrix observed during electron microscopy. Cells of the novel isolate are spherical, motile and divide by binary fission. Strain Pan265T is mesophilic (temperature optimum 30–33 °C), neutrophilic (pH optimum 7.0–8.0), aerobic and heterotrophic. The strain has a genome size of 3.49 Mb and a DNA G + C content of 63.9%. Phylogenetically, the strain belongs to the family Phycisphaeraceae, order Phycisphaerales, class Phycisphaerae. Our polyphasic analysis supports the delineation of strain Pan265T from the known genera in this family. Therefore, we conclude to assign strain Pan265T to a novel species within a novel genus, for which we propose the name Mucisphaera calidilacus gen. nov., sp. nov. The novel species is the type species of the novel genus and is represented by strain Pan265T (= DSM 100697T = CECT 30425T) as type strain.

Psychrobacter halodurans sp. nov. and Psychrobacter coccoides sp. nov., two new slightly halophilic bacteria isolated from marine sediment.

In this study, two bacterial strains designated F2608T and F1192T, isolated from marine sediment sampled in Weihai, PR China, were characterized using a polyphasic approach. Strains were aerobic, Gram-stain-negative and motile. According to the results of phylogenetic analyses based on their 16S rRNA genes, these two strains should be classified under the genus Psychrobacter and they both show <98.5% sequence similarity to their closest relative, Psychrobacter celer JCM 12601T. Moreover, strain F2608T showed 97.5% sequence similarity to strain F1192T. Strain F2608T grew at 4-37 °C (optimum, 30-33 °C) and at pH 6.0-9.0 (optimum, pH 6.5-7.0) in the presence of 0-12% (w/v) NaCl (optimum, 4.0-5.0%). Strain F1192T grew at 4-37 °C (optimum, 30 °C) and at pH 5.5-9.0 (optimum, pH 7.0-7.5) in the presence of 0.5-12% (w/v) NaCl (optimum, 3.0-4.0%). The genomic DNA G+C contents of strain F2608T and strain F1192T were 47.4 and 44.9 %, respectively. Genomic characteristics including average nucleotide identity and digital DNA-DNA hybridization values clearly separated strain F2608T from strain F1192T. The sole isoprenoid quinone in these two strains was ubiquinone 8 and the major cellular fatty acids (>10.0%) were C18:1 ω9c and C17:1 ω8c. The major polar lipids of these two strains were phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Based on the results of polyphasic analysis, the two strains represent two novel species of the genus Psychrobacter, for which the names Psychrobacter halodurans sp. nov. and Psychrobacter coccoides sp. nov. are proposed. The type strains are F2608T (=MCCC 1K05774T=KCTC 82766T) and F1192T (=MCCC 1K05775T=KCTC 82765T), respectively.

Neobacillus paridis sp. nov., an endophyte of Paris polyphylla Smith var. yunnanensis.

A novel endophytic strain, designated YIM B02564T, was isolated from the root of Paris polyphylla Smith var. yunnanensis obtained from Yunnan Province, southwest China. By using a polyphasic approach, cells of the strain were characterized as facultative anaerobic, Gram-positive and rod-shaped. The growth conditions of the strain were found to occur at 20-55°C (optimum, 30°C), pH 6.0-9.0 (optimum, pH 7.0). Strain YIM B02564T can tolerate 2% NaCl concentration. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YIM B02564T belonged to the genus Neobacillus and the 16S rRNA gene sequence similarity values of strain YIM B02564T to the type strains of members of this genus ranged from 95.6 to 97.8%. The DNA G+C content of strain YIM B02564T calculated from the whole genome sequence was 41.6mol%. Values of the ANI and the dDDH between strain YIM B02564T and its closely related Neobacillus species were below 77.9% and 21.5%. Strain YIM B02564T contained MK-7 as the major menaquinone, iso-C15:0 and anteiso-C15:0 as the major fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminophospholipid and four unidentified lipids. It contained meso-diaminopimelic acid in the cell-wall peptidoglycan. On the basis of polyphasic analysis, strain YIM B02564T could be differentiated genotypically and phenotypically from recognized species of the genus Neobacillus. The isolate therefore represents a novel species, for which the name Neobacillus paridis is proposed. The type strain is YIM B02564T (= JCM 34668T = CGMCC 1.18655T).

Evaluating the aerobic xylene-degrading potential of the intrinsic microbial community of a legacy BTEX-contaminated aquifer by enrichment culturing coupled with multi-omics analysis: uncovering the role of Hydrogenophaga strains in xylene degradation

To develop effective bioremediation strategies, it is always important to explore autochthonous microbial community diversity using substrate-specific enrichment. The primary objective of this present study was to reveal the diversity of aerobic xylene-degrading bacteria at a legacy BTEX-contaminated site where xylene is the predominant contaminant, as well as to identify potential indigenous strains that could effectively degrade xylenes, in order to better understand the underlying facts about xylene degradation using a multi-omics approach. Henceforward, parallel aerobic microcosms were set up using different xylene isomers as the sole carbon source to investigate evolved bacterial communities using both culture-dependent and independent methods. Research outcome showed that the autochthonous community of this legacy BTEX-contaminated site has the capability to remove all of the xylene isomers from the environment aerobically employing different bacterial groups for different xylene isomers. Interestingly, polyphasic analysis of the enrichments disclose that the community composition of the o-xylene-degrading enrichment community was utterly distinct from that of the m- and p-xylene-degrading enrichments. Although in each of the enrichments Pseudomonas and Acidovorax were the dominant genera, in the case of o-xylene-degrading enrichment Rhodococcus was the main player. Among the isolates, two Hydogenophaga strains, belonging to the same genomic species, were obtained from p-xylene-degrading enrichment, substantially able to degrade aromatic hydrocarbons including xylene isomers aerobically. Comparative whole-genome analysis of the strains revealed different genomic adaptations to aromatic hydrocarbon degradation, providing an explanation on their different xylene isomer-degrading abilities.

Hymenobacter telluris sp. nov., isolated from soil in South Korea.

Two novel bacterial strains, designated as BT186T and BT505, were isolated from a soil sample collected in South Korea and characterized. Both strains were Gram-stain-negative, rod-shaped, aerobic, circular, convex, and had red-colored colonies. The level of 16S rRNA gene sequence similarity between the strains BT186T and BT505 was 100%, indicating that they represent an identical species. 16S rRNA sequence analysis indicated that strains BT186T and BT505 belong to a distinct lineage within the genus Hymenobacter (family Hymenobacteraceae, order Cytophagales, class Cytophagia, phylum Bacteroidetes, Kingdom Bacteria). Both strains were closely related to Hymenobacter norwichensis DSM 15439T (98.3% 16S rRNA gene similarity), Hymenobacter aquaticus JCM 31653T (96.8%), and Hymenobacter perfusus LMG26000T (96.5%). Strain BT186T was found to have the MK-7 as the major respiratory quinone. The major polar lipid of strain BT186T was identified to be phosphatidylethanolamine (PE). The major cellular fatty acid profiles of strain BT186T were C16:1 ω5c (24.3%), iso-C15:0 (20.3%) and summed feature 3 (C16:1 ω6c/C16:1 ω7c) (19.9%). Characterization based on polyphasic analysis indicated that strains BT186T and BT505 represent novel species of the genus Hymenobacter and the name Hymenobacter telluris sp. nov. is proposed. The type strain of Hymenobacter telluris is BT186T (= KCTC 72338T = NBRC 114968T).

Mongoliitalea daihaiensis sp. nov., isolated from Daihai Lake in Inner Mongolia.

A novel Gram-negative strain, designated X100-76T, was isolated from Daihai Lake in Inner Mongolia, Republic of China. The strain was non-motile, non-spore-forming, long-rod-shaped, oxidase positive and catalase positive. Colonies incubated at 33°C on 2216 marine agar medium for 3days were circular, smooth, transparent, convex with clear edges, orange-red in colour and approximately 1.0mm in diameter. Growth occurred at pH 6.5-12 (optimum pH 7.5), in 0-5.0% (w/v) NaCl (optimum 1.5%, w/v) and at 4-40°C (optimum 28-33°C). Phylogenetic analysis based on 16S rRNA gene sequences showed that X100-76T belongs to the genus Mongoliitalea and is most closely related to Mongoliitalea lutea MIM18T with 98.3% sequence similarity. The total genome size of X100-76T was 4,816,617bp with a G + C content of 39.6%. The digital DNA-DNA hybridization and average nucleotide identity values between strain X100-76T and M. lutea MIM18T were both below the recommended cut-off values. Chemotaxonomic analysis revealed iso-C15:0, Sum Feature 4 (anteiso-C17:1 B and/or iso-C17:1 I), C15:1ω6c, Sum Feature 9 (C16:0 10-methyl and/or iso-C17:1ω9c), C16:0 and iso-C15:1 G as the major fatty acids, menaquinone MK-7 as the major isoprenoid quinone, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and phosphatidylinositol as the major cellular polar lipids. The results of polyphasic analysis demonstrated that X100-76T represents a novel species within the genus Mongoliitalea, for which the name Mongoliitalea daihaiensis sp. nov. is proposed. The type strain is X100-76T (= CGMCC 1.18762T = KCTC 82458T).

Brevibacillus marinus sp. nov., a thermophilic bacterium isolated from deep sea sediment in the South China Sea.

A novel thermophilic bacterium, designated SCSIO 07484T, was isolated from marine sediment sampled in the South China Sea. Growth occurred at 30-60 °C, pH 6.0-8.0 and in the presence of 0-3 % (w/v) NaCl. Cells of strain SCSIO 07484T were rod-shaped and flagellum-forming. No soluble pigment was observed. The phylogenetic analysis of the 16S rRNA gene sequences indicated that SCSIO 07484T belonged to the family Paenibacillaceae and clustered with members of the genus Brevibacillus in the phylogenetic trees with less than 96.2 % similarities. The cell wall contained meso-diaminopimelic acid. Whole-cell hydrolysates contained arabinose, glucose and ribose. The predominant menaquinone was MK-7. Major fatty acids were iso-C16 : 0, iso-C15 : 0, C16 : 0 and iso-C14 : 0. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylmonomethylethanolamine were its diagnostic polar lipids. The whole genome size of strain SCSIO 07484T was 4 079 826 bp with a DNA G+C content of 56.2 mol%, including one circular chromosome of 3 978392 bp and one plasmid of 101434 bp. Based on the polyphasic analysis of strain SCSIO 07484T, it is considered to represent a novel species of the genus Brevibacillus, for which the name Brevibacillus marinus sp. nov. is proposed with the type strain SCSIO 07484T (=DSM 106769T=CGMCC 1.15814T).