Improving plant salt tolerance through Algoriphagus halophytocola sp. nov., isolated from the halophyte Salicornia europaea

Salicornia europaea, commonly known as glasswort, thrives in reclaimed land and coastal areas with high salinity, demonstrating remarkable adaptation to the arid conditions of such environments. Two aerobic, Gram-stain-negative, non-motile, rod-shaped bacterial strains, designated TR-M5T and TR-M9, were isolated from the root of Salicornia europaea plants. These bacteria exhibit plant growth-promoting and salt tolerance-enhancing abilities, which have not been reported in other species of the genus. Both strains produce indole-3-acetic acid (IAA), a plant growth hormone, and synthesize proline, which functions as an osmoprotectant. Additionally, they possess gelatinase and cellulase activities. Cells grow in temperatures from 4 to 42°C (optimum 25°C), pH levels from 6.0 to 9.0 (optimum 7.0), and NaCl concentrations from 0 to 8.0% (optimum 6.0%). The average nucleotide identity and digital DNA-DNA hybridization values of strain TR-M5T with the most closely related type strains for which whole genomes are publicly available were 74.05-77.78% and 18.6-23.1%, respectively. Phylogenetic analysis of their 16S rRNA gene sequences revealed that strains TR-M5T and TR-M9 belong to the genus Algoriphagus. A. locisalis exhibited the highest similarity, sharing a sequence identity of 98.1%. The genomes of TR-M5T and TR-M9 exhibit a G + C content of 43 mol%. This study specifically focuses on the identification and characterization of strain TR-M5T as a novel species within the genus Algoriphagus, which we propose to name Algoriphagus halophytocola sp. nov., highlighting its potential role in enhancing plant growth and salt tolerance in saline environments. The type strain is TR-M5T (KCTC 92720T = GDMCC 1.3797T).

Revealing the comprehensive impact of organic compounds on the partial nitrification-anammox system during incineration leachate treatment: metabolic hierarchy and adaptation

Organics, as widespread pollutants in high-strength ammonia wastewater, typically exert adverse effects on the performance of partial nitrification-anammox (PNA) systems. However, the in-depth knowledge on how microbial consortia respond to these disturbances remains limited. In this study, we unveiled the evolution of complex organic matter flow and its impact on the metabolic hierarchy and adaptation of microbial consortia, employing multi-omics approaches, i.e., 16S amplicon sequencing, metagenomics, and metabolomics. In a two-stage PNA system sequentially treating synthetic wastewater and incineration leachate over 230 days, partial nitrification stayed stable (nitrite accumulation > 97%) while anammox efficiency dropped (nitrogen removal decreased from 86% to 78%). The phenomenon was revealed to be correlated with the evolution of dissolved organic matter (DOM) and xenobiotic organic compounds (XOCs). In the PN stage, ammonia-oxidizing bacteria (AOB) exhibited excellent adaptability through active metabolic regulation after treating leachate. Numerous heterotrophs proliferated to utilize DOM and XOCs, triggering a "boom" state evident in the glycerophospholipid metabolism. However, in the anammox stage, the competition between carbon fixation and central carbon metabolism within autotrophs and heterotrophs became evident. Increased biosynthesis costs inhibited the central metabolism (specific anammox activity decreased by 66%) and the Wood-Ljungdahl pathway of anammox bacteria (AnAOB) in the presence of recalcitrant organics. Additionally, the degradation of organics was limited, exhibiting a "bust" state. This study revealed the metabolic adaption and susceptibility of AOB and AnAOB in response to organics from the leachate, demonstrating the applicability of the two-stage configuration for treating high-strength wastewater containing abundant and diverse organics.

The microbial world in copper sulfide flotation plants (CSFP): Novel insights into bacterial communities and their application as potential pyrite bioreagents

Operations in copper sulfide flotation plants (CSFP) are complex and governed by several variables such as available technologies, reagents, and environmental conditions. However, few investigations are related to studying the microbial communities. These aspects provide a reason to compare the bacterial communities of two CSFP operated with freshwater (FwFlo) and seawater (SwFlo), and study whether indigenous bacteria could be used as pyrite bioreagents. Analyses were determined through next-generation sequencing by Illumina MiSeq System and conducted throughout the entire process: (i) minerals before and after grinding; (ii) final concentrate and concentrate thickener overflow; (iii) final tailings and tailings thickener overflow; and (iv) intake water. Bacterial strains from both plants were tested as potential bioreagents, given their tendency to adhere to pyrite after 5 min. In both CSFP, Proteobacteria (relative abundance from 45.48% to 79.22%), followed by Bacteroidetes (9.37%-44.7%), were the most abundant phyla. Regarding species, Algoriphagus olei (11.35%-43.52%) was present exclusively in FwFlo samples in contact with process water and absent in the mineral before grinding, where Cupriavidus metallidurans (16.05%) and Pseudomonas_uc (11.79%) predominated. In SwFlo samples, Marinobacter flavimaris (3.47%-41.1%), and GU061212-s (10.92%-27.63%), were the most abundant microorganisms. All of them were also detected in intake seawater. The strains with the highest adhesion rate (from 29.84% ± 0.14-100%) were phylogenetically identified as species of the genera Marinobacter, Pseudomonas, Idiomarina, Halomonas, Bacillus, Aerocuccus, and Peribacillus. Our results reveal that bacterial communities are critically dependent on process waters during mining activities, and our data depicted that indigenous bacteria could be used as potential pyrite bioreagents, evidenced by a high adhesion rate. It is thus possible to propose that different indigenous bacterial strains could be considered as new bioreagents to reduce the impact of conventional flotation reagents on health from an environment friendly perspective.

Algoriphagus algorifonticola sp. nov., a marine bacterium isolated from cold spring area of South China Sea

A Gram-stain-negative, aerobic, non-motile, short-rod-shaped bacterium, designated strain hg1T, was isolated from marine sediment within the cold spring area of South China Sea and subjected to a polyphasic taxonomic investigation. Colonies were circular and 1.0–2.0 mm in diameter, coral in colour, convex and smooth after growth on marine agar at 28 °C for 3 days. Strain hg1T was found to grow at 4–40 °C (optimum, 35–37 °C), at pH 6.5–9.0 (optimum, pH 7.5) and with 0–8 % (w/v) NaCl (optimum, 1.5–2 %). Chemotaxonomic analysis showed the sole respiratory quinone was MK-7, and the principal fatty acids are iso-C15 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), and iso-C16 : 0. The major polar lipids are phosphatidylethanolamine, an unidentified phospholipid and five unidentified glycolipids. The DNA G+C content of strain hg1T was 39.6 mol% based on the genome sequence. The comparison of 16S rRNA gene sequence similarities showed that hg1T was closely related to Algoriphagus ornithinivorans DSM 15282T (98.6 % sequence similarity), Algoriphagus zhangzhouensis MCCC 1F01099T (97.9 %) and Algoriphagus vanfongensis DSM 17529T (97.2 %); it exhibited 97.0 % or less sequence similarity to the type strains of other species of the genus Algoriphagus with validly published names. Phylogenetic trees reconstructed with the neighbour-joining, maximum-parsimony and maximum-likelihood methods based on 16S rRNA gene sequences showed that strain hg1T constituted a separate branch with A . ornithinivorans , A. zhangzhouensis , A. vanfongensis in a clade of the genus Algoriphagus . OrthoANI values between strain hg1T and A . ornithinivorans , A. zhangzhouensis and A. vanfongensis were 94.3, 74.1, 73.2 %, respectively, and in silico DNA–DNA hybridization values were 56.2, 18.5 and 18.3 %, respectively. Differential phenotypic properties, together with phylogenetic distinctiveness, demonstrated that strain hg1T is clearly distinct from recognized species of genus Algoriphagus . On the basis of these features, we propose that strain hg1T (=MCCC 1K03570T=KCTC 72111T) represents a novel species of the genus Algoriphagus with the name Algoriphagus algorifonticola sp. nov.

Squash root microbiome transplants and metagenomic inspection for in situ arid adaptations

Arid zones contain a diverse set of microbes capable of survival under dry conditions, some of which can form relationships with plants under drought stress conditions to improve plant health. We studied squash (Cucurbita pepo L.) root microbiome under historically arid and humid sites, both in situ and performing a common garden experiment. Plants were grown in soils from sites with different drought levels, using in situ collected soils as the microbial source. We described and analyzed bacterial diversity by 16S rRNA gene sequencing (N = 48) from the soil, rhizosphere, and endosphere. Proteobacteria were the most abundant phylum present in humid and arid samples, while Actinobacteriota abundance was higher in arid ones. The β-diversity analyses showed split microbiomes between arid and humid microbiomes, and aridity and soil pH levels could explain it. These differences between humid and arid microbiomes were maintained in the common garden experiment, showing that it is possible to transplant in situ diversity to the greenhouse. We detected a total of 1009 bacterial genera; 199 exclusively associated with roots under arid conditions. By 16S and shotgun metagenomics, we identified dry-associated taxa such as Cellvibrio, Ensifer adhaerens, and Streptomyces flavovariabilis. With shotgun metagenomic sequencing of rhizospheres (N = 6), we identified 2969 protein families in the squash core metagenome and found an increased number of exclusively protein families from arid (924) than humid samples (158). We found arid conditions enriched genes involved in protein degradation and folding, oxidative stress, compatible solute synthesis, and ion pumps associated with osmotic regulation. Plant phenotyping allowed us to correlate bacterial communities with plant growth. Our study revealed that it is possible to evaluate microbiome diversity ex-situ and identify critical species and genes involved in plant-microbe interactions in historically arid locations.

Indigenous bacterial community and function in phenanthrene-polluted coastal wetlands: Potential for phenanthrene degradation and relation with soil properties

The Yellow River Delta, adjacent to Shengli Oilfield, has a potential risk of petroleum pollution. In this study, soil samples were collected from phenanthrene (PHE)-polluted (adjacent to abandoned oil well, Zone D) and non-polluted (far away from abandoned oil well, Zone E) coastal wetlands. The influence of PHE pollution on indigenous bacterial community and function, and their relationship with soil characteristics were investigated. The levels of PHE, salinity and NH₄⁺-N were higher in Zone D than in Zone E. PHE-degrading bacteria Achromobacter and Acinetobacter were mainly distributed in Zone E, whereas Halomonas, Marinobacter, and Roseovarius were highly abundant in Zone D. Halomonas and Marinobacter had the potential for denitrification and could achieve PHE degradation through mutual cooperation. PHE pollution could increase the abundance of functional bacteria but reduce the diversity of microbial community. PHE and salinity played key roles in shaping microbial community structure and function. High PHE level inhibited microbial metabolism but stimulated self-protection potential. PHE aerobic degradation associated with the catechol and phthalic acid pathways was found in Zone D, whereas the catechol pathway dominated in Zone E. Interestingly, PHE anaerobic degradation with nitrate reduction also dominated in Zone D, whereas the process coupled with multiple electron acceptors co-existed in Zone E, which was associated with tidal seawater carrying nutrients. This study illustrated the importance of comprehensive consideration of microbial community structure and function under PHE pollution, suggesting indigenous microorganisms as potential microbial consortium for bioremediation in coastal wetlands.

Algoriphagus pacificus sp. nov. and Algoriphagus oliviformis sp. nov., isolated from a mariculture fishpond

Two Gram-stain-negative, catalase-positive, oxidase-negative, rod-shaped, non-flagellated, non-spore-forming and non-motile strains (YJ13C^T and H41^T) were isolated from a mariculture fishpond in PR China. Comparisons based on 16S rRNA gene sequences indicated that YJ13C^T and H41^T shared 16S rRNA gene sequences similarities between 92.6 and 99.2 % with species of the genus Algoriphagus. YJ13C^T only shared 93.8 % 16S rRNA gene sequence similarity with H41^T. The reconstructed phylogenetic and phylogenomic trees indicated that YJ13C^T and H41^T clustered closely with species of the genus Algoriphagus. The calculated pairwise orthologous average nucleotide identity with usearch (OrthoANIu) values between strains YJ13C^T and H41^T and other related strains were all less than 79.5 %. The OrthoANIu value between YJ13C^T and H41^T was only 69.9 %. MK-7 was the predominant respiratory quinone of YJ13C^T and H41^T and their major cellular fatty acids contained iso-C_15 : 0, C_16 : 1 ω7c and C_17 : 1 ω9c. The polar lipids profiles of YJ13C^T and H41^T consisted of phosphatidylethanolamine and several kinds of unidentified lipids. Combining the above descriptions, strains YJ13C^T and H41^T represent two distinct novel species of the genus Algoriphagus, for which the names Algoriphagus pacificus sp. nov. (type strain YJ13C^T=GDMCC 1.2178^T=KCTC 82450^T) and Algoriphagus oliviformis sp. nov. (type strain H41^T=GDMCC 1.2179^T=KCTC 82451^T) are proposed.

The extracellular contractile injection system is enriched in environmental microbes and associates with numerous toxins

The extracellular Contractile Injection System (eCIS) is a toxin-delivery particle that evolved from a bacteriophage tail. Four eCISs have previously been shown to mediate interactions between bacteria and their invertebrate hosts. Here, we identify eCIS loci in 1,249 bacterial and archaeal genomes and reveal an enrichment of these loci in environmental microbes and their apparent absence from mammalian pathogens. We show that 13 eCIS-associated toxin genes from diverse microbes can inhibit the growth of bacteria and/or yeast. We identify immunity genes that protect bacteria from self-intoxication, further supporting an antibacterial role for some eCISs. We also identify previously undescribed eCIS core genes, including a conserved eCIS transcriptional regulator. Finally, we present our data through an extensive eCIS repository, termed eCIStem. Our findings support eCIS as a toxin-delivery system that is widespread among environmental prokaryotes and likely mediates antagonistic interactions with eukaryotes and other prokaryotes.

Algoriphagus aquimaris sp. nov., isolated from seashore sand

Strain F21^T, a marine, aerobic, Gram-negative, rod-shaped bacterium, was isolated from seashore sand sampled in Pohang, Republic of Korea. Cells of strain F21^T were non-motile, catalase-positive, oxidase-positive, non-spore-forming and formed pinkish-red colonies on marine agar. The strain grew optimally at 37°C, pH 7 and in the presence of 2-3 % NaCl (w/v). Analysis of the 16S rRNA gene sequence of strain F21^T revealed that it belonged to the genus Algoriphagus, family Cyclobacteriaceae, with similarity values of 98.1 and 96.8 % to Algoriphagus marincola DSM 16067^T and Algoriphagus ornithinivorans IMSNU 14014^T, respectively. When comparing the genome sequence of F21 ^T with those of the type strains of six species of the genus Algoriphagus, the values obtained were below the thresholds for analyses of average nucleotide identity (71.8-92.7 %) and in silico DNA-DNA hybridization using the Genome-to-Genome Distance Calculator (14.7-75.2 %). The DNA G+C content of strain F21^T was 42.0 mol%. The chemotaxonomic characteristics of F21^T included MK-7 as the predominant isoprenoid quinone, iso-C_15 : 0, iso-C_17 : 0 3-OH and summed feature 3 (C_16 : 1ω6c and/or C_16 : 1ω7c) as major cellular fatty acids, and phosphatidylcholine and phosphatidylethanolamine as major polar lipids. On the basis of phenotypic and chemotaxonomic properties, phylogenetic distinctiveness, and genomic data, we named strain F21^T as Algoriphagus aquimaris sp. nov. and proposed that strain F21^T (=KEMB 2250-007^T= KCTC 72106^T=JCM 33187^T) in the genus Algoriphagus represents a novel species.

Algoriphagus sanaruensis sp. nov., a member of the family Cyclobacteriaceae, isolated from a brackish lake in Hamamatsu, Japan

Strain M8-2^T, which was isolated from brackish lake water (Lake Sanaru) in Japan, was characterized for representation of a novel species in the genus Algoriphagus. Cells of strain M8-2^T were aerobic, Gram-stain-negative and curved-rod-shaped (0.2-0.5 µm wide and 0.7-1.9 µm long). Strain M8-2^T grew optimally at 30 °C, pH 6.5-7.5 and in the presence of 0.5-1.0 % (w/v) NaCl. MK-7 was the sole isoprenoid quinone. The major polar lipids were phosphatidylethanolamine, an unidentified phospholipid and an unidentified polar lipid. The predominant cellular fatty acids were iso-C15 : 0 and anteiso-C15 : 0. Phylogenetic analysis based on its 16S rRNA gene sequence showed that strain M8-2^T belonged to the genus Algoriphagus and was closely related to Algoriphagus aquatilis A8-7^T, Algoriphagus boseongensis BS-R1^T, Algoriphagus aquaeductus T4^T, Algoriphagus olei CC-Hsuan-617^T, Algoriphagusshivajiensis NIO-S3^T and Algoriphagus mannitolivorans DSM 15301^T with sequence similarities of 96.6-97.4 %. Results of average nucleotide identity (<75 %) and digital DNA-DNA hybridization (<19 %) studies showed that M8-2^T was distinct from its phylogenetic relatives. Based on the results of tests for acid production, the predominant cellular fatty acid composition, the DNA G+C content and phylogenetic position, a novel species in the genus Algoriphagus, with the name Algoriphagussanaruensis sp. nov., is proposed for strain M8-2^T (=JCM 31446^T=LMG 29969^T).

Algoriphagus formosus sp. nov., isolated from coastal sediment

A Gram-stain negative, facultative anaerobic, non-motile, strongly orange-pigmented and rod-shaped bacterium, designated XAY3209^T, was isolated from a marine sediment sample collected from the coast of Weihai, China. Strain XAY3209^T was found to grow optimally at 30 °C, at pH 7.0 and in the presence of 2.0% (w/v) NaCl. Its genomic DNA G+C content was 41.9 mol%. On the basis of 16S rRNA gene sequence similarity, the novel isolate belongs to the family Cyclobacteriaceae and is related to the genus Algoriphagus. It shares 98.1% 16S rRNA sequence identity with Algoriphagus marincola, its close phylogenetic relative, but did not show similarities more than 97% with other members of the genus Algoriphagus with validly published names. It contained menaquinone-7 (MK-7) as the sole respiratory quinone, iso-C_15:0, iso-C_17:1 ω9c and Summed feature 3 (C_16:1 ω7c and/or iso-C_15:0 2-OH) as the major fatty acids. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid, one unidentified phospholipid and five unidentified lipids. Results of physiological experiments, biochemical tests and genome average nucleotide identity value (with A. marincola MCCC 1F01203^T) indicate that strain XAY3209^T is genetically and phenotypically distinct from the species of the genus Algoriphagus with validly published names. Strain XAY3209^T therefore represents a novel species, for which the name Algoriphagus formosus sp. nov. is proposed. The type strain is XAY3209^T (= KCTC 52842^T = MCCC 1H00189^T).

Algoriphagus aquaemixtae sp. nov., isolated from water in an estuary environment

A Gram-stain-negative, non-flagellated, non-gliding, aerobic and rod-shaped or ovoid bacterium, designated strain KEM-10T, was isolated from water in an estuary environment in the Yellow Sea, South Korea, and subjected to a polyphasic taxonomic study. Strain KEM-10T grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2.0 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain KEM-10T belonged to the genus Algoriphagus, joining the type strain of Algoriphagus litorisediminis showing 97.4 % sequence similarity. Strain KEM-10T exhibited 16S rRNA gene sequence similarity of 92.2-96.1 % to the type strains of the other Algoriphagus species. Strain KEM-10T contained MK-7 as the predominant menaquinone and iso-C15 : 0 and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) as the major fatty acids. The major polar lipids detected in strain KEM-10T were phosphatidylethanolamine and phosphatidylcholine. The DNA G+C content of strain KEM-10T was 40.6 mol%. The mean DNA-DNA relatedness value between strain KEM-10T and the type strain of A. litorisediminis was 12 %. Differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, revealed that strain KEM-10T is separated from recognized species of the genus Algoriphagus. On the basis of the data presented, strain KEM-10T is considered to represent a novel species of the genus Algoriphagus, for which the name Algoriphagus aquaemixtae sp. nov. is proposed. The type strain is KEM-10T (=KCTC 52839T=NBRC 112780T).

Algoriphagus confluentis sp. nov., isolated from the junction between the ocean and a freshwater lake

A Gram-stain-negative, non-flagellated, non-gliding, aerobic and rod-shaped bacterium, designated HJM-2T, was isolated from the place where the ocean and a freshwater lake meet at Hwajinpo, South Korea, and subjected to a taxonomic study using a polyphasic approach. Strain HJM-2T grew optimally at 30 °C, at pH 7.0-8.0 and in the presence of 1.0-2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain HJM-2T belonged to the genus Algoriphagus, clustering coherently with the type strain of A. taiwanensis. Strain HJM-2T exhibited 16S rRNA gene sequence similarities of 98.6 and 97.2 % to A. taiwanensis CC-RR-82T and A. boseongensis BS-R1T, respectively, and 92.7-96.7 % to the type strains of the other species of the genus Algoriphagus. Strain HJM-2T contained MK-7 as the predominant menaquinone and iso-C15 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and iso-C17 : 0 3-OH as the major fatty acids. The major polar lipids detected in strain HJM-2T were phosphatidylcholine, phosphatidylethanolamine and one unidentified lipid. The DNA G+C content of strain HJM-2T was 45 mol% and mean DNA-DNA relatedness values with the type strains of A. taiwanensis and A. boseongensis were 10-19 %. Differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, revealed that strain HJM-2T is separated from recognized species of the genus Algoriphagus. On the basis of the data presented, strain HJM-2T represents a novel species of the genus Algoriphagus, for which the name Algoriphagus confluentis sp. nov. is proposed. The type strain is HJM-2T ( = KCTC 42704T = NBRC 111222T).

Algoriphagus aestuarii sp. nov., a member of the Cyclobacteriaceae isolated from a tidal-flat sediment of the Yellow Sea in Korea

A Gram-strain-negative, coccoid or oval-shaped, non-motile bacterial strain, designated MDM-1T, was isolated from a tidal-flat sediment on the Korean peninsula. Strain MDM-1T was found to grow optimally at pH 7.0–8.0, at 30 °C and in the presence of 2–3 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain MDM-1T falls within the clade comprising species of the genus Algoriphagus, clustering with the type strains of Algoriphagus halophilus, A. lutimaris, A. chungangensis and A. machipongonensis, with which it exhibited 97.2–98.5 % 16S rRNA gene sequence similarity. Sequence similarities to the type strains of the other recognized species of the genus Algoriphagus were 92.8–97.6 %. Strain MDM-1T was found to contain MK-7 as the predominant menaquinone and iso-C15 : 0 and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) as the major fatty acids. The major polar lipids were identified as phosphatidylcholine, phosphatidylethanolamine and two unidentified lipids. The DNA G+C content of strain MDM-1T was determined to be 42.7 mol% and the mean DNA–DNA relatedness with A. halophilus KCTC 12051T, A. lutimaris S1-3T, A. chungangensis KCTC 23759T, A. machipongonensis DSM 24695T and A. ratkowskyi CIP 107452T was 19.7–5.2 %. Differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain MDM-1T is distinguishable from recognized species of the genus Algoriphagus. On the basis of the data presented, strain MDM-1T is proposed to represent a novel species of the genus Algoriphagus, for which the name Algoriphagus aestuarii sp. nov. is proposed. The type strain is MDM-1T ( = KCTC 42199T = NBRC 110552T).

Negadavirga shengliensis gen. nov., sp. nov., a novel member of the family Cyclobacteriaceae isolated from oil-contaminated saline soil

Four novel Gram-stain-negative, rod-shaped, and non-motile bacterial strains, SLG210-21(T), SLG210-4, SLG210-5 and SLG210-14, were isolated from oil-contaminated saline soil in Shengli Oilfield, China. Growth were observed at 25-42 °C (optimum 37 °C), in the presence of 0-10 % (w/v) NaCl (optimum 0-1 %) and at pH 4.0-10.0 (optimum pH 7.6-8.6). All the strains were positive for catalase and α, β-galactosidase activities and nitrogen reduction, and negative for oxidase activity, glucose fermentation and hydrolysis of agar, starch, gelatin, Tween 40, 60 and 80. The DNA G+C contents of the four strains were 41.3-43.0 mol% and the predominant respiratory quinones were all menaquinone-7. The major fatty acids were iso-C15:0, anteiso-C15:0, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16:1 ω5c and summed feature 9 (iso-C17:1 ω9c and/or 10-methyl C16:0), while the polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, glycolipid, two unidentified phospholipids and two unidentified amino lipids. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the four strains clustered together to form a stable branch in the family Cyclobacteriaceae, and were most closely related to the genera Cyclobacterium and Echinicola with the 16S rRNA gene sequence similarities being 88.6-90.3 and 89.6-91.4 %, respectively. DNA-DNA hybridization between SLG210-21(T) and the other three strains showed the relatedness of 93.8 ± 4.5, 96.2 ± 4.2 and 82.3 ± 4.8 %, respectively. Based on the polyphasic analysis, a novel species in a new genus, Negadavirga Shengliensis gen. nov., sp. nov., is proposed with SLG210-21(T) (=LMG 27737(T) = CGMCC1.12768(T)) [corrected] as the type strain.

Algoriphagus taeanensis sp. nov., isolated from a tidal flat, and emended description of Algoriphagus hitonicola

A Gram-staining-negative, aerobic and rod-shaped bacterial strain, designated HMC4223T, was isolated from a tidal flat in Taean, Republic of Korea. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HMC4223T formed a lineage within the genus Algoriphagus and exhibited highest sequence similarity to Algoriphagus hitonicola 7-UAHT (96.3 %). The major fatty acids of strain HMC4223T were iso-C15 : 0 and summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c). The major respiratory quinone was MK-7. The major polar lipids were phosphatidylethanolamine and five unidentified polar lipids. The DNA G+C content of strain HMC4223T was 48.4 mol%. On the basis of the evidence presented in this study, strain HMC4223T represents a novel species of the genus Algoriphagus , for which the name Algoriphagus taeanensis sp. nov. is proposed, with the type strain HMC4223T ( = KCTC 22709T = NBRC 105728T). An emended description of Algoriphagus hitonicola is also presented.

Algoriphagus zhangzhouensis sp. nov., isolated from mangrove sediment

A Gram-negative, short-rod-shaped and non-motile bacterium, strain 12C11T, was isolated from an oil-degrading consortium, enriched from the Fugong mangrove sediment, Fujian Province of China. Optimum growth was observed at 25 °C, at pH 7.5 and with 4 % (w/v) NaCl. Comparative 16S rRNA gene sequence analysis demonstrated that it shared highest similarity with members of the genus Algoriphagus (97.5–93.4 %), exhibiting 97.5 % sequence similarity to Algoriphagus ornithinivorans IMSNU 14014T, followed by Algoriphagus vanfongensis KMM 6241T (97.2 %); it shared <96.0 % sequence similarity with other members of the genus. Levels of nucleotide sequence similarity between gyrB (DNA gyrase subunit B) genes of strain 12C11T and A. vanfongensis KMM 6241T, A. ornithinivorans IMSNU 14014T, Algoriphagus marincola SW-2T and Algoriphagus hitonicola 7-UAHT were 78.8, 78.6, 75.6 and 77.4 %, respectively. Phylogenetic trees based on these housekeeping genes showed that strain 12C11T and other Algoriphagus strains formed a distinct lineage. The dominant fatty acids were iso-C15 : 0 (32.1 %), C16 : 1ω7c/C16 : 1ω6c (11.6 %), iso-C17 : 1 I/anteiso-C17 : 1 B (10.1 %), iso-C17 : 0 3-OH (9.2 %) and iso-C17 : 1ω9c/C16 : 0 10-methyl (7.1 %), which accounted for 70.0 % of the total fatty acids. DNA–DNA hybridization showed that strain 12C11T shared low DNA–DNA relatedness with A. vanfongensis KMM 6241T and A. ornithinivorans IMSNU 14014T (30.7±0.9 and 30.5±1.8 %, respectively). The G+C content of the chromosomal DNA of strain 12C11T was 38.4 mol%. The major respiratory quinones were MK-7 (96.0 %) and MK-6 (4.0 %). According to its morphology, physiology, fatty acid composition and 16S rRNA gene sequence data, the novel strain most appropriately belongs to the genus Algoriphagus , but can readily be distinguished from known Algoriphagus species. The name Algoriphagus zhangzhouensis sp. nov. is proposed (type strain 12C11T = CGMCC 1.11027T = MCCC 1F01099T = DSM 25035T).

Algoriphagus chungangensis sp. nov., isolated from a tidal flat sediment

A Gram-stain-negative, non-spore-forming, non-motile, strictly aerobic, rod-shaped bacterial strain, designated CAU 1002T, was isolated from a tidal flat sediment and its taxonomic position was investigated using a polyphasic approach. Strain CAU 1002T grew optimally at 30 °C and pH 7.5. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CAU 1002T formed a distinct lineage within the genus Algoriphagus and was most closely related to Algoriphagus lutimaris KCTC 22630T and Algoriphagus halophilus KCTC 12051T (97.75 and 97.74 % 16S rRNA gene sequence similarity, respectively). The strain contained MK-7 as the major isoprenoid quinone and iso-C15 : 0 and C16 : 1ω7c and/or iso-C15 : 0 2-OH (summed feature 3) as the major fatty acids. The cell-wall peptidoglycan of strain CAU 1002T contained meso-diaminopimelic acids. The major whole-cell sugars were glucose, arabinose, sucrose, and ribose. The polar lipid profile was composed of phosphatidylethanolamine, five unidentified aminolipids, one unidentified aminophospholipid, one unidentified phospholipid, one unidentified aminoglycolipid, one unidentified glycolipid and twelve unidentified lipids. The DNA G+C content of strain CAU 1002T was 38.0 mol%. On the basis of phylogenetic inference, phenotypic, chemotaxonomic and genotypic data, strain CAU 1002T should be classified into the genus Algoriphagus as a member of a novel species, for which the name Algoriphagus chungangensis sp. nov. is proposed. The type strain is CAU 1002T ( = KCTC 23759T = CCUG 61890T). The description of the genus Algoriphagus is emended.

Algoriphagus shivajiensis sp. nov., isolated from Cochin back water, India

Novel orange-pigmented, Gram-negative, rod-shaped, non-motile bacteria, designated strains NIO-S3(T) and NIO-S4, were isolated from a water sample collected from Cochin back waters, Thanneermukkom and Arookutty, Kerala, India. Both strains were positive for oxidase and catalase activities, and hydrolyzed gelatin and Tween 40. The predominant fatty acids were iso-C15:0, anteiso-C15:0, iso-C17:0 3OH, C16:1ω7c/C16:1ω6c (summed feature 3) and iso-C17:1ω9c/C16:0 10-methyl (summed feature 9), whereas MK-7 was the major respiratory quinone, and phosphatidylethanolamine, two unidentified phospholipids and one unidentified lipid were the only polar lipids. The DNA G+C content of the two strains was 43.7 and 43.6mol%, respectively. The 16S rRNA gene sequence analysis indicated that they were members of the genus Algoriphagus and closely related to Algoriphagus olei CC-Hsuan-617(T), Algoriphagus aquatilis A8-7(T), Algoriphagus aquaeductus LMG 24398(T) and Algoriphagus mannitolivorans DSM 15301(T), with pairwise sequence similarities of 96.8, 96.6, 96.2 and 96.2%, respectively. DNA-DNA hybridization between strains NIO-S3(T) and NIO-S4 showed a relatedness of 89%. Based on data from the current polyphasic study, the strains are proposed as a novel species of the genus Algoriphagus, for which the name Algoriphagus shivajiensis sp. nov. is proposed. The type strain of A. shivajiensis is NIO-S3(T) (=JCM 17885(T)=MTCC 11066(T)).

Algoriphagus namhaensis sp. nov., isolated from seawater

A Gram-staining-negative, non-motile, non-spore-forming bacterial strain, DPG-3T, was isolated from seawater from the South Sea in Korea, and its taxonomic position was investigated using a polyphasic approach. Strain DPG-3T grew optimally at 30 °C and in the presence of 2 % (w/v) NaCl. In a neighbour-joining phylogenetic tree based on 16S rRNA gene sequences, strain DPG-3T fell within a clade comprising Algoriphagus species and appeared most closely related to Algoriphagus halophilus JC 2051T (96.1 %16S rRNA gene sequence similarity) and Algoriphagus lutimaris S1-3T (96.4 %). The type strains of other Algoriphagus species showed 16S rRNA gene sequence similarities of 92.9–96.0 % with strain DPG-3T. The predominant menaquinone of strain DPG-3T was MK-7. The major fatty acids were iso-C15 : 0 and iso-C15 : 0 2-OH and/or C16 : 1ω7c (summed feature 3). The major polar lipids detected in strain DPG-3T were phosphatidylcholine, phosphatidylethanolamine and an unidentified lipid. The genomic DNA G+C content was 44.8 mol%. On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain DPG-3T is considered to represent a novel species of the genus Algoriphagus, for which the name Algoriphagus namhaensis sp. nov. is proposed. The type strain is DPG-3T ( = KCTC 23419T = CCUG 60523T).

Algoriphagus aquaeductus sp. nov., isolated from a freshwater pipe

A Gram-staining-negative, aerobic to microaerophilic, rod-shaped, red-coloured bacterium, strain T4T, was isolated from a freshwater pipe on Tenerife island. A polyphasic taxonomic study was performed in order to characterize the strain in detail. The isolate is surrounded by a slime capsule, occurs singly, in the form of short chains, or in aggregates, and exhibits catalase and oxidase activities. Growth was observed at 15–42 °C. Optimum growth occurred at pH 8 with mono- and disaccharides, followed by polysaccharides and deoxysaccharides, but the bacterium utilized only a restricted spectrum of alcohols, alditols, amides, amines, carboxylic acids and amino acids. Strain T4T tolerated concentrations of 0–4 % (w/v) NaCl and contained MK-7 as predominant isoprenoid quinone as well as carotenoids, but lacked pigments of the flexirubin type. The predominant fatty acids were iso-C15 : 0 (32.2 %), summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c; 22.5 %), and iso-C17 : 0 3-OH (7.9 %). Major polar lipids were phosphatidylethanolamine, phospholipids, aminophospholipids and other lipids of unknown character. The DNA G+C content was approximately 41.8 mol%. The sequence of the 16S-rRNA gene assigned strain T4T to the CFB group, forming a coherent cluster with species of the genus Algoriphagus with the highest similarity of 98.8 % to Algoriphagus aquatilis A8-7T. DNA–DNA hybridization revealed 37.5 % relatedness to strain A8-7T. Based on morphological, physiological and molecular properties as well as on phylogenetic distinctiveness, strain T4T should be placed into the genus Algoriphagus as a novel species, for which the name Algoriphagus aquaeductus sp. nov. (type strain T4T  = DSM 19759T  = LMG 24398T  = NCIMB 14399T) is proposed.

Algoriphagus machipongonensis sp. nov., co-isolated with a colonial choanoflagellate

A Gram-negative, non-motile, non-spore-forming bacterial strain, PR1(T), was isolated from a mud core sample containing colonial choanoflagellates near Hog Island, Virginia, USA. Strain PR1(T) grew optimally at 30 °C and with 3 % (w/v) NaCl. Strain PR1(T) contained MK-7 as the major menaquinone as well as carotenoids but lacked pigments of the flexirubin-type. The predominant fatty acids were iso-C(15 : 0) (29.4 %), iso-C(17 : 1)ω9c (18.5 %) and summed feature 3 (C(16 : 1)ω6c and/or C(16 : 1)ω7c; 11.3 %). The major polar lipids detected in strain PR1(T) were phosphatidylethanolamine, an unknown phospholipid, an aminophospholipid, an aminolipid and two lipids of unknown character. The DNA G+C content was 38.7 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain PR1(T) fell within the cluster comprising the genus Algoriphagus and was most closely related to Algoriphagus halophilus JC 2051(T) (95.4 % sequence similarity) and Algoriphagus lutimaris S1-3(T) (95.3 % sequence similarity). The 16S rRNA gene sequence similarity between strain PR1(T) and the type strains of other species of the genus Algoriphagus were in the range 91-95 %. Differential phenotypic properties and phylogenetic and genetic distinctiveness of strain PR1(T) demonstrated that this strain was distinct from other members of the genus Algoriphagus, including its closest relative, A. halophilus. Based on phenotypic, chemotaxonomic, phylogenetic and genomic data, strain PR1(T) should be placed in the genus Algoriphagus as a representative of a novel species, for which the name Algoriphagus machipongonensis sp. nov. is proposed. The type strain is PR1(T) (= ATCC BAA-2233(T) = DSM 24695(T)).

Algoriphagus jejuensis sp. nov., isolated from seawater

A Gram-negative, pink-pigmented, non-motile, strictly aerobic rod, designated CNU040T, was isolated from seawater from the coast of Jeju Island in Korea. The temperature, pH and NaCl ranges for growth were 4–30 °C, pH 5.5–10.0 and 0–5.0 % NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CNU040T belonged to a distinct lineage in the genus Algoriphagus and exhibited high sequence similarity with Algoriphagus terrigena DS-44T (98.3 %) and Algoriphagus alkaliphilus AC-74T (96.6 %) and lower sequence similarity (<96.0 %) with all other members of the genus Algoriphagus. DNA–DNA relatedness between strain CNU040T and A. terrigena KCTC 12545T was 44.5 %. The DNA G+C content of the isolate was 48.5 mol% and the major respiratory quinone was menaquinone-7. The major cellular fatty acids were iso-C15 : 0 (28.6 %) and summed feature 3 (consisting of iso-C15 : 0 2-OH and/or C16 : 1ω7c; 24.0 %). The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, one unknown amino lipid, one unknown aminophospholipid and three unknown polar lipids. On the basis of phenotypic, phylogenetic and genotypic data, strain CNU040T represents a novel species within the genus Algoriphagus, for which the name Algoriphagus jejuensis sp. nov. is proposed. The type strain is CNU040T ( = KCTC 22647T  = JCM 16112T).

Algoriphagus faecimaris sp. nov., isolated from coastal sediment

A Gram-negative, non-motile, non-sporulating bacterial strain, designated LYX05(T), was isolated from coastal sediment of Qingdao, China, on the coast of the Yellow Sea. Strain LYX05(T) was aerobic and heterotrophic. The strain grew optimally at 37 °C and pH 7.5 and in the presence of 2% (w/v) NaCl. Colonies were 1-2 mm in diameter, circular, reddish orange and shiny with entire edges on marine agar medium. Cells were rods (0.3-0.5 µm wide and 0.8-1.6 µm long). The dominant fatty acids were iso-C(15:0) (40.82%) and C(16:0) (10.45%). The DNA G+C content was 42.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain LYX05(T) was phylogenetically related to the members of the genus Algoriphagus and the closest relative was Algoriphagus hitonicola 7-UAH(T) (95.8% 16S rRNA gene sequence similarity). On the basis of phenotypic, chemotaxonomic and phylogenetic data, strain LYX05(T) was considered to represent a novel species of the genus Algoriphagus, for which the name Algoriphagus faecimaris sp. nov. is proposed. The type strain is LYX05(T) (=JCM 16561(T) =DSM 23095(T) =LMG 25474(T)).

Fontibacter flavus gen. nov., sp. nov., a member of the family ‘Cyclobacteriaceae’, isolated from a hot spring

The taxonomic position of a bright orange-pigmented bacterial strain, designated CC-GZM-130T, isolated from a water sample of the Guan-zing-ling hot spring, southern Taiwan, was studied. The strain was able to grow on nutrient agar at 25–40 °C and in the presence of 1–3 % (w/v) NaCl. Comparative analyses of the 16S rRNA gene sequence showed that the isolate was grouped in the vicinity of the genus Aquiflexum with the highest sequence similarity of 92.1 % to the type strain of Aquiflexum balticum, followed by sequence similarities of 92.0, 91.6 and 91.5 % to the type strains of Algoriphagus ornithinivorans, Algoriphagus hitonicola and Belliella baltica, respectively. The polyamine pattern showed that the major compound was sym-homospermidine. The quinone system was menaquinone MK-7. The polar lipid profile was composed predominantly of phosphatidylethanolamine, three polar lipids and one aminolipid. Minor amounts of other lipids were also detectable. The main characteristics of the fatty acid profiles of strain CC-GZM-130T, B. baltica and Aquiflexum balticum were similar, with iso-C15 : 0, iso-C17 : 1 ω9c and iso-C17 : 0 3-OH as the major fatty acids, but some qualitative and quantitative differences were observed. The DNA G+C content of the novel strain was 53.2 mol%. The isolate clearly differed genotypically and phenotypically from representatives of the most closely related genera. On the basis of these differences, a novel species in a new genus, Fontibacter flavus gen. nov., sp. nov., is proposed with CC-GZM-130T (=CCUG 57694T=CCM 7650T) as the type strain of the type species.