Hymenobacter jejuensis sp. nov., a UV radiation-tolerant bacterium isolated from Jeju Island

Hymenobacter endophyticus sp. nov., isolated from wheat leaf tissue

A bacterium, designated strain ZK17L-C2T, was isolated from the leaf tissues of wheat (Triticum aestivum) collected in Chengdu, Sichuan Province, PR China. It is aerobic, non-motile, Gram-negative, rod-shaped and red-to-pink in colour. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain ZK17L-C2T belonged to the genus Hymenobacter and was most closely related to Hymenobacter rigui KCTC 12533T (98.68 %) and Hymenobacter metallilatus 9PBR-2T (98.19 %). Digital DNA-DNA hybridization (dDDH) values between strain ZK17L-C2T and these two type strains were 26.6 and 26.5 %, and average nucleotide identity (ANI) values were 84.9 and 84.8 %, respectively; these values are lower than the proposed and generally accepted species boundaries for dDDH and ANI. The genomic DNA G+C content of strain ZK17L-C2T was 59.4 mol%. It can grow at pH 5.5-7.5 and 15-30 °C, which is different from the closely related type strains. The major fatty acids of strain ZK17L-C2T were iso-C15 : 0, C16 : 0 and C18 : 0. Overall, the results from biochemical, chemical taxonomy and phylogenetic analyses indicate that strain ZK17L-C2T (=CGMCC 1.19373T=KCTC 92184 T) represents a new species of the genus Hymenobacter, for which the name Hymenobacter endophyticus sp. nov. is proposed.

Description of Hymenobacter sediminicola sp. nov., isolated from contaminated sediment

A polyphasic taxonomic study was conducted on two Gram-negative, non-sporulating, non-motile bacterial strains, S2-20-2^T and S2-21-1, isolated from a contaminated freshwater sediment in China. Comparative 16S rRNA gene sequence studies revealed a clear affiliation of two strains with Bacteroidetes, which showed the highest pairwise sequence similarities with Hymenobacter duratus BT646^T (99.3%), Hymenobacter psychrotolerans Tibet-IIU11^T (99.3%), Hymenobacter kanuolensis T-3^T (97.6%), Hymenobacter swuensis DY53^T (96.9%), Hymenobacter tenuis POB6^T (96.8%), Hymenobacter seoulensis 16F7G^T (96.7%), and Hymenobacter rigui KCTC 12533^T (96.5%). The phylogenetic analysis based on 16S rRNA gene sequences showed that two strains formed a clear phylogenetic lineage with the genus Hymenobacter. Major fatty acids were identified as iso-C_15:0, anteiso-C_15:0, and summed feature 3 (C_16:1 ω6c and/or C_16:1 ω7c/t) and summed feature 4 (iso-C_17:1 I and/or anteiso-C_17:1 B). Major cellular polar lipids were identified as phosphatidylethanolamine, three unidentified aminolipids, an unidentified aminophosopholipid and an unidentified lipid. The respiratory quinone was detected as MK-7 and the genomic DNA G + C content was determined to be 57.9% (genome) for type strain S2-20-2^T and 57.7 mol% (HPLC) for strain S2-21-1. The observed ANI and dDDH values between strain S2-20-2^T and its closely related strains were 75.7-91.4% and 21.2-43.9%, respectively. Based on physiological, biochemical, genetic and genomic characteristics, we propose that strains S2-20-2^T and S2-21-1 represent a novel species of the genus Hymenobacter, for which the name Hymenobacter sediminicola sp. nov. is proposed. The type strain is S2-20-2^T (= CGMCC 1.18734^T = JCM 35801^T).

Hymenobacter siberiensis sp. nov., isolated from a marine sediment of the East Siberian Sea and Hymenobacter psoromatis sp. nov., isolated from an Antarctic lichen

Gram-stain-negative, strictly aerobic, red-pink-coloured, rod-shaped and non-motile bacterial strains PAMC 29290, PAMC 29294T and PAMC 29296 were isolated from marine surface sediment sampled in the East Siberian Sea and strains PAMC 26553 and PAMC 26554T were obtained from an Antarctic lichen. Strains PAMC 29290, PAMC 29294T and PAMC 29296 were closely related to Hymenobacter artigasi (98.8 % 16S rRNA gene similarity), Hymenobacter antarcticus (97.3 %) and Hymenobacter glaciei (96.9 %), and PAMC 26553 and PAMC 26554T showed high similarity to Hymenobacter ginsengisoli (97.0 %), Hymenobacter rivuli (96.1 %) and Hymenobacter setariae (95.9 %). Genomic relatedness analyses showed that strains PAMC 29290, PAMC 29294T and PAMC 29296 could be distinguished from H. artigasi by average nucleotide identity (ANI; 93.1–93.2 %) and digital DNA–DNA hybridization (dDDH; 50.3–51.0 %) values. Strains PAMC 26553 and PAMC 26554T could be clearly distinguished from H. ginsengisoli with ANI values <79.8 % and dDDH values <23.3 %. The major fatty acids of strains PAMC 29290, PAMC 29294T and PAMC 29296 were C15 : 0 iso (21.0–26.0 %), summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c; 17.4–18.2 %), C15 : 0 anteiso (12.7–19.1 %) and summed feature 4 (C17 : 1 iso I and/or anteiso B; 8.6–16.1 %) and those of strains PAMC 26553 and PAMC 26554T were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c; 20.7–22.2 %), C15 : 0 anteiso (17.5–19.7 %) and summed feature 4 (C17 : 1 iso I and/or anteiso B; 15.5–18.1 %). The major respiratory quinone was MK-7. The genomic DNA G+C contents were 60.6–60.8 mol%. The polar lipids of PAMC 29294T were found to consist of phosphatidylethanolamine, four unidentified aminolipids, an unidentified aminophospholipid and five unidentified lipids; those of PAMC 26554T were phosphatidylethanolamine, three unidentified aminolipids, four unidentified aminophospholipid and two unidentified lipids. The distinct phylogenetic position and some physiological characteristics distinguished the novel strains from closely related type strains in the genus Hymenobacter . Thus, two novel species are proposed, with the names Hymenobacter siberiensis sp. nov. (type strain, PAMC 29294T=KCTC 82466T=JCM 34574T) and Hymenobacter psoromatis sp. nov. (type strain, PAMC 26554T=KCTC 82464T=JCM 34572T), respectively.

Hymenobacter armeniacus sp. nov. and Hymenobacter montanus sp. nov., two radiation-resistant bacteria from soil

Two bacterial strains, designated BT189T and BT664T, were isolated from soil sampled in the Republic of Korea. Phylogenetic analysis based on the 16S rRNA gene sequences showed that strains BT189T and BT664T belonged to the genus Hymenobacter , family Hymenobacteraceae (order Cytophagales ). The 16S rRNA genes of the two strains shared a sequence similarity of 93.7 %. The closely related species of strain BT189T were Hymenobacter rubidus DG7BT (97.1 % 16S rRNA similarity) and Hymenobacter terrae DG7AT (96.7 %). The closest related species to strain BT664T were Hymenobacter sedentarius DG5BT (95.3 %) and Hymenobacter terrenus MIMtkLc17T (95.2 %). The genome sizes of strains BT189T and BT664T were 5 285 287 and 5 475 357 bp, respectively. The genomic DNA G+C contents of strains BT189T and BT664T were 63.2 and 59.3 mol%, respectively. The main fatty acids of strain BT189T were iso-C15 : 0, anteiso-C15 : 0 and summed feature 3 (C16 : 1  ω6c/C16 : 1  ω7c), and those of strain BT664T were iso-C15 : 0, C16 : 1  ω5c and summed feature 3 (C16 : 1  ω6c/C16 : 1  ω7c). The main polar lipid in both strains was phosphatidylethanolamine and the predominant respiratory quinone was MK-7, supporting the affiliation of these strains with the genus Hymenobacter . Based on the results of biochemical, chemotaxonomic and phylogenetic analyses, two novel species, Hymenobacter armeniacus BT189T (=KCTC 72341T=NBRC 114843T) and Hymenobacter montanus BT664T (KACC 21967T=NBRC 114856T), are proposed.

Extremophilic taxa predominate in a microbial community of photovoltaic panels in a tropical region

Photovoltaic panels can be colonized by a highly diverse microbial diversity, despite life-threatening conditions. Although they are distributed worldwide, the microorganisms living on their surfaces have never been profiled in tropical regions using 16S rRNA high-throughput sequencing and PICRUst metagenome prediction of functional content. In this work, we investigated photovoltaic panels from two cities in southeast Brazil, Sorocaba and Itatiba, using these bioinformatics approach. Results showed that, despite significant differences in microbial diversity (p < 0.001), the taxonomic profile was very similar for both photovoltaic panels, dominated mainly by Proteobacteria, Bacteroidota and lower amounts of Cyanobacteria phyla. A predominance of Hymenobacter and Methylobacterium-Methylorubrum was observed at the genus level. We identified a microbial common core composed of Hymenobacter, Deinococcus, Sphingomonas, Methylobacterium-Methylorubrum, Craurococcus-Caldovatus, Massilia, Noviherbaspirillum and 1174-901-12 sharing genera. Predicted metabolisms focused on specific genes associated to radiation and desiccation resistance and pigments, were detected in members of the common core and among the most abundant genera. Our results suggested that taxonomic and functional profiles investigated were consistent with the harsh environment that photovoltaic panels represent. Moreover, the presence of stress genes in the predicted functional content was a preliminary evidence that microbes living there are a possibly source of metabolites with biotechnological interest.

Hymenobacter taeanensis sp. nov., radiation resistant bacterium isolated from coastal sand dune

An aerobic, Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, and light pink-colored bacterial strain, designated TS19^T, was isolated from a sand sample obtained from a coastal sand dune after exposure to 3 kGy of gamma radiation. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that the isolate was a member of the genus Hymenobacter and was most closely related to H. wooponensis WM78^T (98.3% similarity). Strain TS19^T and H. wooponensis showed resistance to gamma radiation with D₁₀ values (i.e., the dose required to reduce the bacterial population by tenfold) of 7.3 kGy and 3.5 kGy, respectively. The genome of strain TS19^T consists of one contig with 4,879,662 bp and has a G + C content of 56.2%. The genome contains 3,955 protein coding sequences, 44 tRNAs, and 12 rRNAs. The predominant fatty acids of strain TS19^T were iso-C_15:0, summed feature 4 (iso-C_17:1 I and/or anteiso-C_17:1 B), summed feature 3 (C_16:1 ω6c and/or C_16:1 ω7c), and C_16:1 ω5c. The major polar lipids were phosphatidylethanolamine, and one unidentified aminophospholipid. The main respiratory quinone was menaquinone-7. Based on the phylogenetic, physiological, and chemotaxonomic characteristics, strain TS19^T represents a novel species, for which the name Hymenobacter taeanensis sp. nov. is proposed. The type strain is TS19^T (= KCTC 72897^T = JCM 34023^T).

Hymenobacter guriensis sp. nov., and Hymenobacter duratus sp. nov., Radiation-Resistant Species Isolated from Soil in South Korea

Two novel Gram-stain-negative, non-motile, aerobic, rod-shaped, circular, convex, red-colored and UV-tolerant strains BT594^T and BT646^T were isolated from soil collected in Guri city (37° 36' 0″ N, 127° 9' 0″ E) and Gwangju city (37° 22' 0″ N, 127° 17' 0″ E), respectively, South Korea. 16S rDNA sequence analysis indicated that strains BT594^T and BT646^T belong to a distinct lineage within the genus Hymenobacter (family Hymenobacteraceae, order Cytophagales, class Cytophagia, phylum Bacteroidetes, kingdom Bacteria). The 16S rDNA gene sequence similarity between the two strains BT594^T and BT646^T was 96.2%. The strain BT594^T was closely related to Hymenobacter psychrotolerans Tibet-IIU11^T (97.0% 16S rDNA gene similarity) and Hymenobacter tibetensis XTM003^T (96.3%). The strain BT646^T was closely related to Hymenobacter psychrotolerans Tibet-IIU11^T (98.6%), Hymenobacter kanuolensis T-3 ^T (96.8%) and Hymenobacter perfusus LMG 26000 ^T (96.7%). The two strains were found to have the same quinone system, with MK-7 as the major respiratory quinone. The major polar lipids of strains BT594^T and BT646^T were phosphatidylethanolamine (PE) and aminophospholipids (APL). The major cellular fatty acids of strain BT594^T were anteiso-C_15:0 (17.9%), iso-C_15:0 (16.1%) and summed feature 3 (C_16:1 ω6c / C_16:1 ω7c) (10.0%). The major cellular fatty acids of strain BT646^T were summed feature 3 (C_16:1 ω6c / C_16:1 ω7c) (18.3%), C_16:0 (17.2%) and summed feature 4 (iso-C_17:1 I / anteiso-C_17:1 B) (14.5%). Based on the polyphasic analysis, strains BT594^T and BT646^T can be suggested as two novel bacterial species within the genus Hymenobacter and the proposed names are Hymenobacter guriensis and Hymenobacter duratus, respectively. The type strain of Hymenobacter guriensis is BT594^T (= KCTC 21863 ^T = NBRC 114853 ^T) and the type strain of Hymenobacter duratus is BT646^T (= KCTC 21915 ^T = NBRC 114854 ^T).

Hymenobacter busanensis sp. nov., radiation-resistant species isolated from soil in South Korea

Two bacterial strains designated as MA3^T and BT182 were isolated from a soil sample in South Korea. Cells of the two strains were Gram-stain-negative, non-motile, rod-shaped and formed red colonies on R2A agar at 25 °C. The 16S rRNA genes of the two strains shared a sequence similarity of 99.8%. Both strains shared the highest 16S rRNA gene similarity of 96.8% with Hymenobacter edaphi NL^T, followed by Hymenobacter paludis KBP-30^T (96.3%), Hymenobacter coalescens WW84^T (96.3%) and Hymenobacter gummosus ANT-18^T (96.3%). Growth was observed at 15-37 °C (optimum 30 °C), pH 6-8 (optimum pH 7) and in the presence up to 1% NaCl. The genome size of strains MA3^T and BT182 is 4.9 Mb and 4.8 Mb, respectively. The genomic G + C content of both strains is 62.0 mol%. The main polar lipid of the strains was phosphatidylethanolamine, the only respiratory quinone detected was menaquinone-7 and the major fatty acids were anteiso-C_15:0, iso-C_15:0, summed feature 4 (iso-C_17:1 I/anteiso-C_17:1 B) and summed feature 3 (C_16:1 ω6c/C_16:1 ω7c), supporting the affiliation of these strains with the genus Hymenobacter. Based on the phylogenetic, genotypic, phenotypic and chemotaxonomic data, strains MA3^T and BT182 represent a novel species of the genus Hymenobacter, for which the name Hymenobacter busanensis is proposed. The type strain is MA3^T (= KCTC 72631^T = NBRC 114193^T).

The wasted chewing gum bacteriome

Here we show the bacteriome of wasted chewing gums from five different countries and the microbial successions on wasted gums during three months of outdoors exposure. In addition, a collection of bacterial strains from wasted gums was set, and the biodegradation capability of different gum ingredients by the isolates was tested. Our results reveal that the oral microbiota present in gums after being chewed, characterised by the presence of species such as Streptococcus spp. or Corynebacterium spp., evolves in a few weeks to an environmental bacteriome characterised by the presence of Acinetobacter spp., Sphingomonas spp. and Pseudomonas spp. Wasted chewing gums collected worldwide contain a typical sub-aerial biofilm bacteriome, characterised by species such as Sphingomonas spp., Kocuria spp., Deinococcus spp. and Blastococcus spp. Our findings have implications for a wide range of disciplines, including forensics, contagious disease control, or bioremediation of wasted chewing gum residues.

Pontibacter pudoricolor sp. nov., and Pontibacter russatus sp. nov. radiation-resistant bacteria isolated from soil

Gram-stain-negative, aerobic, non-flagellated, red-colored strains BT214^T and BT326^T were isolated from soil collected in Uijeongbu city, Korea. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strains BT214^T and BT326^T formed a distinct lineage within the family Hymenobacteraceae (order Chitinophagales, class Chitinophagia) and were most closely related to members of the genus Pontibacter, Pontibacter populi HLY7-15^T (96.9% 16S rRNA gene sequence similarity) and Pontibacter amylolyticus 9-2^T (96.1%), respectively. Optimal growth of two strains occurred at 25 °C, pH 7.0 and in the absence of NaCl. The predominant cellular fatty acids were summed feature 4 (iso-C_17:1 I/anteiso-C_17:1 B) and iso-C_15:0. The major respiratory quinone of two strains was MK-7. The major polar lipid of two strains was phosphatidylethanolamine. Biochemical, chemotaxonomic and phylogenetic analyses indicated that strains BT214^T and BT326^T represent novel bacterial species within the genus Pontibacter, for which the names Pontibacter pudoricolor and Pontibacter russatus are proposed. The type strains of Pontibacter pudoricolor and Pontibacter russatus are BT214^T and BT326^T, respectively.