Algibacter lectus gen. nov., sp. nov., a novel member of the family Flavobacteriaceae isolated from green algae

Cultivable epiphytic bacteria of the Chlorophyta Ulva sp.: diversity, antibacterial, and biofilm-modulating activities

AIMS

Macroalgae harbor a rich epiphytic microbiota that plays a crucial role in algal morphogenesis and defense mechanisms. This study aims to isolate epiphytic cultivable microbiota from Ulva sp. surfaces. Various culture media were employed to evaluate a wide range of cultivable microbiota. Our objective was to assess the antibacterial and biofilm-modulating activities of supernatants from isolated bacteria.

METHODS AND RESULTS

Sixty-nine bacterial isolates from Ulva sp. were identified based on 16S rRNA gene sequencing. Their antibacterial activity and biofilm modulation potential were screened against three target marine bacteria: 45%, mostly affiliated with Gammaproteobacteria and mainly grown on diluted R2A medium (R2Ad), showed strong antibacterial activity, while 18% had a significant impact on biofilm modulation. Molecular network analysis was carried out on four bioactive bacterial supernatants, revealing new molecules potentially responsible for their activities.

CONCLUSION

R2Ad offered the greatest diversity and proportion of active isolates. The molecular network approach holds promise for both identifying bacterial isolates based on their molecular production and characterizing antibacterial and biofilm-modulating activities.

An invasive herbivorous fish (Siganus rivulatus) influences both benthic and planktonic microbes through defecation and nutrient excretion

Direct and indirect impacts by invasive animals on plants and other animals through predation and competition have been evidenced in many ecosystems. For instance, the rabbitfish Siganus rivulatus, originating from the Red Sea, is now the most abundant species in costal habitats of South-Eastern Mediterranean Sea where it overgrazes algae. However, little is known about its impacts on microbes through release of metabolic wastes and feces. We used a mesocosm experiment to test the effect of S. rivulatus on planktonic and benthic microbial communities. Excretion of dissolved nutrients by fish resulted in higher concentrations of dissolved inorganic nitrogen (NH₄, NO₂/NO₃). This increase in availability of N was associated with higher N content in macroalgae, higher biomass of phytoplankton, higher abundance of bacterioplankton and shift in the structure of planktonic bacterial communities. The feces released mostly under the shelters where the fish rest at night, led to significant increases in diversity of sediment bacterial communities and shifts in their structure. The impact of S. rivulatus on planktonic microbes was related to the indirect bottom-up effect induced by excreted dissolved nutrients while its effect on benthic microbes was due to the direct release of both organic matter and microbes present in feces. Overall, this first evidence of the impacts of invasive species on planktonic and benthic microbes highlights that ongoing changes in fish biodiversity could have ecosystem-wide consequences.

Isolation, Diversity and Characterization of Ulvan-Degrading Bacteria Isolated from Marine Environments

In this study, we aimed to isolate bacteria capable of degrading the polysaccharide ulvan from the green algae Ulva sp. (Chlorophyta, Ulvales, Ulvaceae) in marine environments. We isolated 13 ulvan-degrading bacteria and observed high diversity at the genus level. Further, the genera Paraglaciecola, Vibrio, Echinicola, and Algibacter, which can degrade ulvan, were successfully isolated for the first time from marine environments. Among the 13 isolates, only one isolate (Echinicola sp.) showed the ability not only to produce externally expressed ulvan lyase, but also to be periplasmic or on the cell surface. From the results of the full-genome analysis, lyase was presumed to be a member of the PL25 (BNR4) family of ulvan lyases, and the bacterium also contained the sequence for glycoside hydrolase (GH43, GH78 and GH88), which is characteristic of other ulvan-degrading bacteria. Notably, this bacterium has a unique ulvan lyase gene not previously reported.

Algibacter onchidii sp. nov., a symbiotic bacterium isolated from a marine invertebrate

A novel symbiotic bacterium, designated strain XY-114^T, was isolated from the cerata of an Onchidium marine invertebrate species collected in the South China Sea. Strain XY-114^T was an aerobic, Gram-stain-negative, non-motile and short rod-shaped bacterium (0.5-0.8 µm wide and 1.0-1.5 µm long) without flagellum. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain XY-114^T belonged to the genus Algibacter with the highest similarity of 97.2 % to the closest phylogenetic relative Algibacter aestuarii KYW371^T. Cells grew at 15-37 °C (optimum, 30 °C), at pH 5.5-9.0 (optimum 7.0-8.0) and at NaCl concentrations of 0.5-5.0 % (w/v; optimum 1.5-3.0 %). The major fatty acids (>10 %) were summed feature 3 (comprising C_16 : 1  ω7c and/or C_16 : 1  ω6c), iso-C_15 : 0, iso-C_15 : 1 G and iso-C_17 : 0 3-OH. The predominant polar lipid was phosphatidylethanolamine. The predominant respiratory quinone was MK-6. Flexirubin-type pigments were absent. The genome size of strain XY-114^T was 3.4 Mbp, with 34.9 mol% of DNA G+C content. The average nucleotide identity, digital DNA-DNA hybridization and amino acid identity values between strain XY-114^T and A. aestuarii KYW371^T were 74.5 %, 17.0±1.8 % and 73.9 %. Characterization based on phylogenetic, phenotypic, chemotaxonomic and genomic evidence demonstrated that strain XY-114^T represents a novel species of the genus Algibacter, for which the name Algibacter onchidii sp. nov. is proposed. The type strain is XY-114^T (=KCTC 72217^T=MCCC 1K03606^T).

Extremophiles in Soil Communities of Former Copper Mining Sites of the East Harz Region (Germany) Reflected by Re-Analyzed 16S rRNA Data

The east and southeast rim of Harz mountains (Germany) are marked by a high density of former copper mining places dating back from the late 20th century to the middle age. A set of 18 soil samples from pre- and early industrial mining places and one sample from an industrial mine dump have been selected for investigation by 16S rRNA and compared with six samples from non-mining areas. Although most of the soil samples from the old mines show pH values around 7, RNA profiling reflects many operational taxonomical units (OTUs) belonging to acidophilic genera. For some of these OTUs, similarities were found with their abundances in the comparative samples, while others show significant differences. In addition to pH-dependent bacteria, thermophilic, psychrophilic, and halophilic types were observed. Among these OTUs, several DNA sequences are related to bacteria which are reported to show the ability to metabolize special substrates. Some OTUs absent in comparative samples from limestone substrates, among them Thaumarchaeota were present in the soil group from ancient mines with pH > 7. In contrast, acidophilic types have been found in a sample from a copper slag deposit, e.g., the polymer degrading bacterium Granulicella and Acidicaldus, which is thermophilic, too. Soil samples of the group of pre-industrial mines supplied some less abundant, interesting OTUs as the polymer-degrading Povalibacter and the halophilic Lewinella and Halobacteriovorax. A particularly high number of bacteria (OTUs) which had not been detected in other samples were found at an industrial copper mine dump, among them many halophilic and psychrophilic types. In summary, the results show that soil samples from the ancient copper mining places contain soil bacterial communities that could be a promising source in the search for microorganisms with valuable metabolic capabilities.

Phylogenomic Analyses of a Clade Within the Family Flavobacteriaceae Suggest Taxonomic Reassignments of Species of the Genera Algibacter, Hyunsoonleella, Jejuia, and Flavivirga, and the Proposal of Pseudalgibacter gen. nov. and Pseudalgibacter alginicilyticus comb. nov

The family Flavobacteriaceae forms a major branch within the phylum Bacteroidetes. Whole-genome sequence-based analysis could significantly improve the accuracy of taxonomic assignments. In this study, phylogenomic analyses were carried out to revisit the taxonomic status of a clade of the family Flavobacteriaceae. Taking genome-based phylogeny as the primary guideline and average amino acid identity and phenotypic information as supplements, the following taxonomic proposals were put forward: Arenitalea lutea should be reclassified into the genus Algibacter; Algibacter aquaticus should be reclassified into the genus Flavivirga; Jejuia pallidilutea and Algibacter aestuarii should be reclassified into the genus Hyunsoonleella; Algibacter alginicilyticus should be reclassified into the novel genus Pseudalgibacter gen. nov. This study builds up a solid framework for taxonomic decisions of a clade of the family Flavobacteriaceae and will contribute to further insights into the evolution of this family.

Reclassification of Algibacter wandonensis as a Later Heterotypic Synonym of Algibacter lectus Based on Whole-Genome Sequence Analysis

The genus Algibacter belongs to the family Flavobacteriaceae of the Bacteroidetes, and all members of this genus were isolated from marine environments. Among the Algibacter species, two members, Algibacter lectus KMM 3902^T and Algibacter wandonensis WS-MY22^T, were isolated from green algae and sediment around a brown algae respectively. The 16S rRNA gene sequences of these two type strains possess 99.4% sequence similarity. In this study, further studies were undertaken to clarify the taxonomic assignments of the two species. Whole-genome sequence analysis showed that the similarities for other phylogenetic markers are also very high (i.e. 99.9% for gyrB, 99.6% for recA and 99.9% for rpoD). Average nucleotide identity, average amino acids identity and digital DNA-DNA hybridization value between A. lectus KMM 3902^T and A. wandonensis WS-MY22^T are 98.3%, 98.6% and 89.4% respectively, all clearly exceed suggested species delineation thresholds. Furthermore, phylogenetic trees based on sequences of 16S rRNA gene and up-to-date bacterial core gene set (UBCG) consisting of 92 genes provided additional evidence that A. lectus KMM 3902^T and A. wandonensis WS-MY22^T are very closely related. In addition, a review of their profiles indicated that A. lectus KMM 3902^T and A. wandonensis WS-MY22^T did not present pronounced differences at phenotypic and chemotaxonomic levels. Based on these evidence, we propose that A. wandonensis should be reclassified as later heterotypic synonyms of A. lectus.

Direct Comparison of Fecal and Gut Microbiota in the Blue Mussel (Mytilus edulis) Discourages Fecal Sampling as a Proxy for Resident Gut Community

Bivalves have ecological and economic importance but information regarding their associated microbiomes is lacking. As suspension feeders, bivalves capture and ingest a myriad of particles, and their digestive organs have a high throughput of particle-associated microbiota. To better understand the complement of transient and resident microbial communities, standard methods need to be developed. For example, fecal sampling could represent a convenient proxy for the gut microbiome and is simple, nondestructive, and allows for sampling of individuals through time. The goal of this study was to evaluate fecal sampling as a reliable proxy for gut microbiome assessment in the blue mussel (Mytilus edulis). Mussels were collected from the natural environment and placed into individual sterilized microcosms for 6 h to allow for fecal egestion. Feces and gut homogenates from the same individuals were sampled and subjected to 16S rRNA gene amplicon sequencing. Fecal communities of different mussels resembled each other but did not resemble gut communities. Fecal communities were significantly more diverse, in terms of amplicon sequence variant (ASV) richness and evenness, than gut communities. Results suggested a mostly transient nature for fecal microbiota. Nonetheless, mussels retained a distinct resident microbial community in their gut after fecal egestion that was dominated by ASVs belonging to Mycoplasma. The use of fecal sampling as a nondestructive substitute for direct sampling of the gut is strongly discouraged. Experiments that aim to study solely resident bivalve gut microbiota should employ an egestion period prior to gut sampling to allow time for voidance of transient microbes.

Yeosuana marina sp. nov., isolated from shallow-sea hydrothermal systems off Kueishantao Island

A novel Gram-stain-negative, non-flagellated, non-motile, rod-shaped (0.4-0.6×1.8-2.5 µm), aerobic bacterial strain, designated JLT21^T, was isolated from seawater of a shallow-sea hydrothermal system. Growth occurred with 0-4.0 % (w/v) NaCl (optimum, 2.0 % NaCl), at 8-45 °C (optimum, 25 °C) and at pH 3.0-10.0 (optimum, pH 7.0). Analysis of 16S rRNA gene sequences revealed that strain JLT21^T showed the highest 16S rRNA gene sequence similarity to Gaetbulibacter aquiaggeris KEM-8^T (97.2 %), Gaetbulibacter marinus IMCC1914^T (96.9 %) and Yeosuana aromativorans GW1-1^T (96.9 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain JLT21^T clustered with Y. aromativorans GW1-1^T. The predominant respiratory quinone of strain JLT21^T was menaquinone-6 (MK-6). Polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, three unidentified glycolipids and four unidentified lipids. The major fatty acids of strain JLT21^T were iso-C_15 : 0 (21.7 %), C_16 : 1  ω6c/ω7c (11.5 %) and iso-C_17 : 0 3-OH (10.9 %). The DNA G+C content of strain JLT21^T was 32.6 %. On the basis of polyphasic analysis, strain JLT21^T is considered to represent a novel species of the genus Yeosuana, for which the name Yeosuana marina sp. nov. is proposed. The type strain of Yeosuana marina is JLT21^T (=CGMCC 1.15787^T=JCM 31511^T). The study helps us better understand the bacterial species in the shallow-sea hydrothermal system and their adaptations to the hydrothermal environment.

Algibacter marinivivus sp. nov., isolated from the surface of a marine red alga

A Gram-stain-negative, non-flagellated bacterium, designated ZY111T, was isolated from the surface of a marine red alga, which was collected from the coast in Weihai, Shandong Province, PR China. Strain ZY111T exhibited growth at 4–37 °C (optimum, 25–28 °C) in the presence of 0–8.0 % (w/v) NaCl (optimum, 2.0–4.0% NaCl) and at pH 6.5–9.5 (optimum, pH 7.0–8.0). The 16S rRNA gene sequence analysis revealed that strain ZY111T belonged to the genus Algibacter , with Algibacter amylolyticus DSM 29199T as its closest relative (97.7 % similarity). The averagenucleotide identity value of strain ZY111T with A. amylolyticus DSM 29199T was 79.03 %. The digitalDNA–DNA hybridization value of strain ZY111T with A. amylolyticus DSM 29199T was 22.40 %. The dominant fatty acids were iso-C15 : 0, iso-C15 : 1 G, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH. The sole respiratory quinone was determined to be menaquinone-6. The polar lipid profile of strain ZY111T consisted of phosphatidylethanolamine, two unidentified aminolipids and three unidentified lipids. The G+C content was 31.9 mol%. The phenotypic, chemotaxonomic and phylogenetic data clearly showed that strain ZY111T represents a novel species of the genus Algibacter , for which the name Algibacter marinivivus sp. nov. is proposed. The type strain is ZY111T (=KCTC 62373T=MCCC 1H00295T).

Mesohalobacter halotolerans gen. nov., sp. nov., isolated from a marine solar saltern

A Gram-stain-negative, non-motile, fine rod or short filament shaped, jacinth pigmented bacterium, designated strain WDS2C27^T, was isolated from a marine solar saltern in Wendeng, Weihai, PR China (37°31'5″ N, 122°1'47″ E). Growth of WDS2C27^T occurred at 20-42 °C (optimum 37 °C) and pH 6.5-8.5 (optimal pH 7.0-8.0). Optimal growth occurred in modified marine broth containing 6 % (w/v) NaCl. The major polar lipids in WDS2C27^T were phosphatidylethanolamine, two unidentified aminolipids and one unidentified lipid. The major respiratory quinone of WDS2C27^T was MK-6. The dominant fatty acids were iso-C_15 : 0 and anteiso-C_15 : 0. The DNA G+C content was 35.0 mol%. The nucleotide sequence of the 16S rRNA gene indicated that the most closely related strain was Psychroflexus planctonicus X15M-8^T (92.0 % over 1452 bp). WDS2C27^T showed 60.7 % average amino acid identity, 55.6 % percentage of conserved proteins, 75.0 % average nucleotide identity and 13.1 % digital DNA-DNA hybridization identity with the type species of the genus Psychroflexus, Psychroflexus torquis ATCC 700755^T. The phenotypic and genotypic properties and phylogenetic inference indicated that WDS2C27^T could be assigned to a novel species within a novel genus, for which the name Mesohalobacter halotolerans gen. nov., sp. nov. is proposed. Strain WDS2C27^T (=MCCC 1H00133^T=KCTC 52044^T) is the type strain.

Algibacter pacificus sp. nov., isolated from a deep-sea seamount

The Gram-stain-negative, rod-shaped, yellow-pigmented and facultative anaerobic bacterial strain, designated H164T, was isolated from seawater collected from the Caroline Seamounts in the Pacific Ocean. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain H164T was related to the genus Algibacter and had highest 16S rRNA gene sequence similarity to Algibacter wandonensis WS-MY22T (97.4 %). The major cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0, iso-C15 : 1 G, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH. The predominant menaquinone was MK-6. The polar lipid profile contained phosphatidylethanolamine, one unidentified aminolipid and two unidentified lipids. The genomic DNA G+C content of strain H164T was 33.2 mol%. The values of in silico DNA–DNA hybridization (isDDH) and average nucleotide identity (ANI) between strain H164T and A. wandonensis KCTC 32381T were 26.10 and 81.88 %. The isDDH and ANI values between strain H164T and Algibacter lectus DSM 15365T were 25.40 and 81.79 %. Combined data from phenotypic, phylogenetic, isDDH and ANI analyses demonstrated that strain H164T represents a novel species of the genus Algibacter , for which we propose the name Algibacter pacificus sp. nov. (type strain H164T=KCTC 72432T=CGMCC 1.17117T).

Hansen K, Isaksson J, Ullsten S, H. Hansen E, Hammer Andersen J. Anti-Bacterial Effect and Cytotoxicity Assessment of Lipid 430 Isolated from Algibacter sp

Two bacterial isolates from the Barents Sea, both belonging to the genus Algibacter, were found to yield extracts with anti-bacterial bioactivity. Mass spectrometry guided dereplication and purification of the active extracts lead to the isolation of the same active principle in both extracts. The structure of the bioactive compound was identified via mass spectrometry and nuclear resonance spectroscopy and it turned out to be the known lipopeptide Lipid 430. We discovered and determined its previously unknown anti-bacterial activity against Streptococcus agalactiae and revealed a cytotoxic effect against the A2058 human melanoma cell line at significantly lower concentrations compared to its anti-bacterial concentration. Flow cytometry and microscopy investigations of the cytotoxicity against the melanoma cell line indicated that Lipid 430 did not cause immediate cell lysis. The experiments with melanoma cells suggest that the compound functions trough more complex pathways than acting as a simple detergent.

Synergetic alginate conversion by a microbial consortium of hydrolytic bacteria and methanogens

Sludge, of which alginate-like biomaterial is a major organic component, is an increasing environmental problem. Thus, efficient anaerobic degradation of alginate provides a new method for sludge utilization. In this study, anaerobic alginate hydrolytic bacteria (AHB) were proposed to enrich with methanogens synergetically to reduce the inhibition of intermediate metabolites. The COD of produced methane reached 80.7 ± 1.9% (n = 4) of initial alginate COD. After considering the microbial growth (8%-18% of COD), a good COD balance indicated that alginate was fully consumed and the main final metabolites were methane and CO₂. Methanogenesis could promote alginate conversion by AHB. The enriched bacteria for alginate degradation in this study were different from that of former known AHB. The metabolic pathway of alginate degradation was revealed by metagenomics, in which oligo-alginate lyase was detected in twelve bacteria, and typical carbon metabolic pathways to convert alginate to methane were identified. More studies of bacterial isolation and biofuel production are still needed in the future.

Analysis of 1,000 Type-Strain Genomes Improves Taxonomic Classification of Bacteroidetes

Although considerable progress has been made in recent years regarding the classification of bacteria assigned to the phylum Bacteroidetes, there remains a need to further clarify taxonomic relationships within a diverse assemblage that includes organisms of clinical, piscicultural, and ecological importance. Bacteroidetes classification has proved to be difficult, not least when taxonomic decisions rested heavily on interpretation of poorly resolved 16S rRNA gene trees and a limited number of phenotypic features. Here, draft genome sequences of a greatly enlarged collection of genomes of more than 1,000 Bacteroidetes and outgroup type strains were used to infer phylogenetic trees from genome-scale data using the principles drawn from phylogenetic systematics. The majority of taxa were found to be monophyletic but several orders, families and genera, including taxa proposed long ago such as Bacteroides, Cytophaga, and Flavobacterium but also quite recent taxa, as well as a few species were shown to be in need of revision. According proposals are made for the recognition of new orders, families and genera, as well as the transfer of a variety of species to other genera. In addition, emended descriptions are given for many species mainly involving information on DNA G+C content and (approximate) genome size, both of which can be considered valuable taxonomic markers. We detected many incongruities when comparing the results of the present study with existing classifications, which appear to be caused by insufficiently resolved 16S rRNA gene trees or incomplete taxon sampling. The few significant incongruities found between 16S rRNA gene and whole genome trees underline the pitfalls inherent in phylogenies based upon single gene sequences and the impediment in using ordinary bootstrapping in phylogenomic studies, particularly when combined with too narrow gene selections. While a significant degree of phylogenetic conservation was detected in all phenotypic characters investigated, the overall fit to the tree varied considerably, which is one of the probable causes of misclassifications in the past, much like the use of plesiomorphic character states as diagnostic features.

Thalassorhabdus aurantiaca gen. nov., sp. nov., a new member of the family Flavobacteriaceae isolated from seawater in South Korea

A novel Gram-negative, orange pigmented, strictly aerobic bacterium, designated strain IP9^T, was isolated from seawater at the sea shore of Incheon Eulwang-ri beach, South Korea. Cells of strain IP9^T were observed to be straight or slightly curved rods and colonies to be round and convex. Strain IP9^T was found to be catalase and oxidase positive, and non-motile. Growth was observed in the temperature range of 10-37 °C (optimum at 30 °C), pH range of 6-10 (optimum at pH 7-8) and salt concentration range of 0-7% (w/v) NaCl (optimum at 0-1%). On the basis of 16S rRNA gene sequence similarity and phylogenetic analysis, strain IP9^T was found to be related to the members of the family Flavobacteriaceae, being closely related to Hwangdonia seohaensis KCTC 32177^T (95.3% sequence similarity). The DNA G + C content of the novel strain was determined to be 39.1 mol%. The major polar lipids were found to be phosphatidylethanolamine, three unidentified aminoglycolipids and two unidentified glycolipids. The major fatty acids (> 10%) were identified as iso-C_15:0 and iso-C_17:0 3-OH. The predominant quinone was found to be menaquinone 6 (MK-6). Based on the biochemical, phylogenetic and physiological data, we conclude that strain IP9^T (= KCTC 52523^T = JCM 31732^T) represents the type species of a novel genus of the family Flavobacteriaceae for which the name Thalassorhabdus aurantiaca gen. nov., sp. nov. is proposed.

Agar-degrading bacteria isolated from Antarctic macroalgae

This study describes the taxonomic diversity of pigmented, agar-degrading bacteria isolated from the surface of macroalgae collected in King George Island, Antarctica. A total of 30 pigmented, agarolytic bacteria were isolated from the surface of the Antarctic macroalgae Adenocystis utricularis, Monostroma hariotii, Iridaea cordata, and Pantoneura plocamioides. Based on the 16S rRNA data, the agarolytic isolates were affiliated to the genera Algibacter, Arthrobacter, Brachybacterium, Cellulophaga, Citricoccus, Labedella, Microbacterium, Micrococcus, Salinibacterium, Sanguibacter, and Zobellia. Isolates phylogenetically related to Cellulophaga algicola showed the highest agarase activity in culture supernatants when tested at 4 and 37 °C. This is the first investigation of pigmented agar-degrading bacteria, members of microbial communities associated with Antarctic macroalgae, and the results suggest that they represent a potential source of cold-adapted agarases of possible biotechnological interest.

Isolation and Complete Genome Sequence of Algibacter alginolytica sp. nov., a Novel Seaweed-Degrading Bacteroidetes Bacterium with Diverse Putative Polysaccharide Utilization Loci

The members of the phylum Bacteroidetes are recognized as some of the most important specialists for the degradation of polysaccharides. However, in contrast to research on Bacteroidetes in the human gut, research on polysaccharide degradation by marine Bacteroidetes is still rare. The genus Algibacter belongs to the Flavobacteriaceae family of the Bacteroidetes, and most species in this genus are isolated from or near the habitat of algae, indicating a preference for the complex polysaccharides of algae. In this work, a novel brown-seaweed-degrading strain designated HZ22 was isolated from the surface of a brown seaweed (Laminaria japonica). On the basis of its physiological, chemotaxonomic, and genotypic characteristics, it is proposed that strain HZ22 represents a novel species in the genus Algibacter with the proposed name Algibacter alginolytica sp. nov. The genome of strain HZ22, the type strain of this species, harbors 3,371 coding sequences (CDSs) and 255 carbohydrate-active enzymes (CAZymes), including 104 glycoside hydrolases (GHs) and 18 polysaccharide lyases (PLs); this appears to be the highest proportion of CAZymes (∼7.5%) among the reported strains in the class Flavobacteria Seventeen polysaccharide utilization loci (PUL) are predicted to be specific for marine polysaccharides, especially algal polysaccharides from red, green, and brown seaweeds. In particular, PUL N is predicted to be specific for alginate. Taking these findings together with the results of assays of crude alginate lyases, we prove that strain HZ22(T) can completely degrade alginate. This work reveals that strain HZ22(T) has good potential for the degradation of algal polysaccharides and that the structure and related mechanism of PUL in strain HZ22(T) are worth further research.

Isolation and characterization of a novel marine Bacteroidetes as Algitalea ulvae gen. nov., sp. nov., isolated from the green alga Ulva pertusa

A polyphasic taxonomic investigation was performed on a bacterial strain, 38-Ka-2(T), which was isolated from the green alga Ulva pertusa Kjellman (Chlorophyta) in Hokkaido, Japan. The bacterial cells were observed to be golden-yellow coloured, Gram-negative, strictly aerobic, non-spore-forming, non-motile and rod-shaped. Phylogenetic analyses based on the 16S rRNA gene sequence indicated that the new strain is a member of the family Flavobacteriaceae within the phylum Bacteroidetes and that it shows high sequence similarity (94.8 %) to Aquimarina addita JC2680(T). The genomic DNA G+C content of strain 38-Ka-2(T) was determined to be 36 mol%; MK-6 was identified as the major menaquinone; and the presence of iso-C15:0, C18:0 and iso-C17:0 3-OH as the major (>10 %) cellular fatty acids. The polar lipid profile was found to consist of phosphatidylethanolamine, an unidentified glycolipid and two unidentified lipids. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, strain 38-Ka-2(T) is considered to represent a novel genus for which the name Algitalea ulvae gen. nov., sp. nov. is proposed. The type strain of A. ulvae is 38-Ka-2(T) (=KCTC 32994(T) = NBRC 110017(T)).

Algibacter amylolyticus sp. nov., isolated from intertidal sediment

A Gram-reaction-negative, rod-shaped, yellow-pigmented, motile by gliding bacterial strain, designated RU-4-M-4T, was isolated from intertidal sediment of Sakhalin Island in Russia. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain RU-4-M-4T was related to the genus Algibacter and had highest 16S rRNA gene sequence similarity with Algibacter pectinivorans KACC 14153T (97.2 %). The major cellular fatty acids were iso-C15 : 0 3-OH, C15 : 0 and iso-C15 : 1 G. The predominant menaquinone was MK-6. The polar lipid profile contained phosphatidylethanolamine, three unidentified aminolipids and two unidentified lipids. The genomic DNA G+C content of strain RU-4-M-4T was 36.4 mol%. Combined data from phenotypic, phylogenetic and DNA–DNA relatedness studies demonstrated that strain RU-4-M-4T is a representative of a novel species of the genus Algibacter , for which we propose the name Algibacter amylolyticus sp. nov. (type strain RU-4-M-4T = LMG 28383T = DSM 29199T).

Flavirhabdus iliipiscaria gen. nov., sp. nov., isolated from intestine of flounder (Paralichthys olivaceus) and emended descriptions of the genera Flavivirga, Algibacter, Bizionia and Formosa

A Gram-stain-negative, orange-coloured, rod-shaped bacterium, designated strain Th68T, was isolated from the intestine of flounder (Paralichthys olivaceus). The isolate required sea salts for growth. Gliding motility was not observed. Flexirubin-type pigments were present. 16S rRNA gene sequence analysis indicated that strain Th68T represented a distinct phyletic line within the family Flavobacteriaceae with less than 96.1 % similarity to members of the recognized genera of the family. The DNA G+C content was 33.0 mol%. The major fatty acids were iso-C15 : 0, iso-C15 : 1 G, iso-C17 : 0 3-OH and iso-C15 : 0 3-OH. The major polar lipids were phosphatidylethanolamine, two unidentified aminolipids and two unidentified polar lipids. Menaquinone 6 (MK-6) was the only respiratory quinone. On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain Th68T represents a novel species of a new genus in the family Flavobacteriaceae , for which the name Flavirhabdus iliipiscaria gen. nov., sp. nov. is proposed. The type strain of Flavirhabdus iliipiscaria is Th68T ( = JCM 18637T = KCTC 32141T).

Algibacter psychrophilus sp. nov., a psychrophilic bacterium isolated from marine sediment

A Gram-stain-negative, aerobic, yellow-pigmented, flexirubin-negative, rod-shaped, non-motile and psychrophilic bacterial strain, PAMC 27237T, was isolated from marine sediment of the Ross Sea, Antarctica. Strain PAMC 27237T grew at 0-20 °C (optimally at 17 °C), at pH 5.0-9.5 (optimally at pH 7.0) and in the presence of 0-3.5 % (w/v) NaCl (optimally at 1.5-2.5 %). The major fatty acids (≥5 %) were iso-C17 : 0 3-OH, C17 : 0 2-OH, anteiso-C15 : 0, summed feature 3 (C16 : 1ω6c/C16 : 1ω7c), iso-C15 : 0 3-OH, anteiso-C17 : 1ω9c, anteiso-C15 : 1 A, iso-C16 : 0 3-OH and iso-C15 : 1 G. The major polar lipids were phosphatidylethanolamine, two unidentified aminolipids, four unidentified lipids and a glycolipid. The major respiratory quinone was MK-6. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain PAMC 27237T belongs to the genus Algibacter, showing high similarities with the type strains of Algibacter agarivorans (97.2 %), Algibacter agarilyticus (97.0 %) and Algibacter mikhailovii (96.4 %). Average nucleotide identity values between strain PAMC 27237T and the type strains of A. agarivorans and A. agarilyticuswere 83.1 and 84.2 %, respectively, and mean genome-to-genome distances were 22.4-24.2 %, indicating that strain PAMC 27237T is clearly distinguished from the most closely related species of the genus Algibacter. The genomic DNA G+C content calculated from genome sequences was 33.5 mol%. Based on the phenotypic, chemotaxonomic and phylogenetic data presented, strain PAMC 27237T is considered to represent a novel species of the genus Algibacter, for which the name Algibacter psychrophilus sp. nov. is proposed. The type strain is PAMC 27237T ( = KCTC 42130T = JCM 30370T).

Draft Genome Sequences of Marine Flavobacterium Algibacter lectus Strains SS8 and NR4

Here, we present the draft genome sequences of a zeaxanthin-producing flavobacterium, Algibacter lectus strains SS8 and NR4, isolated from coastal sediment and rock surfaces in Hakodate, Japan, respectively. This genomic information represents the first Algibacter genome sequences, which will help us to elucidate the biology and evolution of Flavobacteriaceae bacteria.

Ochrovirga pacifica gen. nov., sp. nov., a novel agar-lytic marine bacterium of the family Flavobacteriaceae isolated from a seaweed

A strain designated as S85(T) was isolated from a seaweed collected from coastal area of Chuuk State in Micronesia. The strain was gram-negative, rod-shaped, and non-motile and formed yellow colonies on the SWY agar (0.2 % yeast extract and 1.5 % agar in seawater) and Marine agar 2216. The strain grew at pH 5-9 (optimum, pH 8), at 15-40 °C (optimum, 25-28 °C), and with 1-9 % (w/v) NaCl (optimum, 3 %). The phylogenetic analysis based on 16S rRNA gene sequence showed that strain S85(T) was related to Lutibacter litoralis CL-TF09(T) and Maritimimonas rapanae A31(T) with 91.4 % and with 90.5 % similarity, respectively. The dominant fatty acids were iso-C15:0, iso-C15:0 3-OH and iso-C17:0 3-OH, C16:0 3-OH and summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH). The major isoprenoid quinone was MK-6. The DNA G+C content of the type strain was 34.6 mol %. The major polar lipids were phosphatidylethanolamine, an unknown glycolipid and two unknown polar lipids. Based on this polyphasic taxonomic data, strain S85(T) stands for a novel species of a new genus, and we propose the name Ochrovirga pacifica gen. nov., sp. nov. The type strain of O. pacifica is S85(T) (=KCCM 90106 =JCM 18327(T)).

Algibacter wandonensis sp. nov., isolated from sediment around a brown algae (Undaria pinnatifida) reservoir

A Gram-stain-negative, non-flagellated, rod-shaped bacterial strain able to move by gliding, designated WS-MY22(T), was isolated from sediment around a brown algae reservoir located on Wando in South Korea. It grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain WS-MY22(T) clustered coherently with the type strains of Algibacter lectus and Algibacter undariae. It exhibited sequence similarity of 99.4 and 98.9 % to the type strains of A. lectus and A. undariae, respectively, and of 95.1-96.6 % to those of the other species of the genus Algibacter. Strain WS-MY22(T) contained MK-6 as the predominant menaquinone and iso-C15 : 1 G and iso-C17 : 0 3-OH as the major fatty acids. The major polar lipids of strain WS-MY22(T) were phosphatidylethanolamine and two unidentified lipids. The DNA G+C content of strain WS-MY22(T) was 35.8 mol% and its DNA-DNA relatedness with A. lectus KCTC 12103(T) and A. undariae WS-MY9(T) was 31 and 19 %, respectively. The phylogenetic and genetic distinctiveness and differential phenotypic properties revealed that strain WS-MY22(T) is separate from other species of the genus Algibacter. On the basis of the data presented, strain WS-MY22(T) is considered to represent a novel species of the genus Algibacter, for which the name Algibacter wandonensis sp. nov. is proposed. The type strain is WS-MY22(T) ( = KCTC 32381(T) = CECT 8301(T)).

The genome of the alga-associated marine flavobacterium Formosa agariphila KMM 3901T reveals a broad potential for degradation of algal polysaccharides

In recent years, representatives of the Bacteroidetes have been increasingly recognized as specialists for the degradation of macromolecules. Formosa constitutes a Bacteroidetes genus within the class Flavobacteria, and the members of this genus have been found in marine habitats with high levels of organic matter, such as in association with algae, invertebrates, and fecal pellets. Here we report on the generation and analysis of the genome of the type strain of Formosa agariphila (KMM 3901(T)), an isolate from the green alga Acrosiphonia sonderi. F. agariphila is a facultative anaerobe with the capacity for mixed acid fermentation and denitrification. Its genome harbors 129 proteases and 88 glycoside hydrolases, indicating a pronounced specialization for the degradation of proteins, polysaccharides, and glycoproteins. Sixty-five of the glycoside hydrolases are organized in at least 13 distinct polysaccharide utilization loci, where they are clustered with TonB-dependent receptors, SusD-like proteins, sensors/transcription factors, transporters, and often sulfatases. These loci play a pivotal role in bacteroidetal polysaccharide biodegradation and in the case of F. agariphila revealed the capacity to degrade a wide range of algal polysaccharides from green, red, and brown algae and thus a strong specialization of toward an alga-associated lifestyle. This was corroborated by growth experiments, which confirmed usage particularly of those monosaccharides that constitute the building blocks of abundant algal polysaccharides, as well as distinct algal polysaccharides, such as laminarins, xylans, and κ-carrageenans.

Algibacter undariae sp. nov., isolated from a brown algae reservoir

A Gram-stain-negative, non-flagellated, rod-shaped bacterial strain able to move by gliding, designated WS-MY9(T), was isolated from a brown algae reservoir in South Korea. Strain WS-MY9(T) grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain WS-MY9(T) clustered with the type strain of Algibacter lectus with a bootstrap resampling value of 100 %. Strain WS-MY9(T) exhibited 16S rRNA gene sequence similarity values of 98.5 and 96.7 % to the type strains of A. lectus and Algibacter mikhailovii, respectively, and less than 96.1 % sequence similarity to other members of the family Flavobacteriaceae. Strain WS-MY9(T) contained MK-6 as the predominant menaquinone and anteiso-C15 : 0, iso-C17 : 0 3-OH, iso-C15 : 1 G and iso-C15 : 0 as the major fatty acids. The major polar lipids of strain WS-MY9(T) were phosphatidylethanolamine and two unidentified lipids. The DNA G+C content of strain WS-MY9(T) was 35.0 mol% and its DNA-DNA relatedness value with A. lectus KCTC 12103(T) was 15 %. The phylogenetic and genetic distinctiveness and differential phenotypic properties revealed that strain WS-MY9(T) is separate from the two recognized species of the genus Algibacter. On the basis of the data presented, strain WS-MY9(T) represents a novel species of the genus Algibacter, for which the name Algibacter undariae sp. nov. is proposed. The type strain is WS-MY9(T) ( = KCTC 32259(T) = CCUG 63684(T)).

Algibacter agarivorans sp. nov. and Algibacter agarilyticus sp. nov., isolated from seawater, reclassification of Marinivirga aestuarii as Algibacter aestuarii comb. nov. and emended description of the genus Algibacter

Two yellow-pigmented, rod-shaped, non-motile, Gram-reaction-negative and aerobic bacterial strains, designated KYW560T and KYW563T, were isolated from seawater collected from Gwangyang Bay, Republic of Korea. The isolates required sea salts for growth. Flexirubin-type pigments were absent. The common major cellular fatty acids (>5 % of total) of the two strains were C16 : 0, C18 : 0, iso-C15 : 0, anteiso-C15 : 0, iso-C15 : 1 G, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). Strain KYW560T also contained iso-C15 : 0 3-OH and C20 : 1ω9c as major fatty acids. The main polar lipids were phosphatidylethanolamine, an unidentified aminolipid and two unidentified lipids. The predominant isoprenoid quinone was MK-6. The DNA G+C contents of strains KYW560T and KYW563T were 41.0±0.7 and 38.3±0.4 mol% (mean±sd of three determinations), respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolates belonged to the family Flavobacteriaceae , and were related to the genus Algibacter . Based on data from this taxonomic study using a polyphasic approach, it is proposed that the isolates represent novel species of the genus Algibacter , for which the names Algibacter agarivorans sp. nov. (type strain, KYW560T = KCTC 23855T = JCM 18285T) and Algibacter agarilyticus sp. nov. (type strain, KYW563T = KCTC 23857T = JCM 18275T) are proposed. Reclassification of Marinivirga aestuarii as Algibacter aestuarii comb. nov. and emended description of the genus Algibacter are also proposed.

Sabulilitoribacter multivorans gen. nov., sp. nov., a polysaccharide-degrading bacterium of the family Flavobacteriaceae isolated from seashore sand

A Gram-negative, aerobic, non-flagellated, non-gliding and rod-shaped bacterial strain, designated M-M16(T), was isolated from seashore sand around a seaweed farm on the South Sea, South Korea, and its taxonomic position was investigated by using a polyphasic study. Strain M-M16(T) grew optimally at 30 °C, at pH 7.0-8.0 and in the presence of 2 % (w/v) NaCl. Strain M-M16(T) exhibited the highest 16S rRNA gene sequence similarity values to the type strains of Gaetbulibacter lutimaris (96.5 %) and Flaviramulus basaltis (95.8 %). Neighbour-joining and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences revealed that strain M-M16(T) clustered with the type strains of Gaetbulibacter species and F. basaltis. Strain M-M16(T) contained MK-6 as the predominant menaquinone and iso-C15:1 G, iso-C15:0 and iso-C17:0 3-OH as the major fatty acids. The major polar lipids detected in strain M-M16(T) were phosphatidylethanolamine and one unidentified lipid. The DNA G+C content of strain M-M16(T) was 37.4 mol%. The phylogenetic and chemotaxonomic data and other phenotypic properties revealed that strain M-M16(T) represents a novel genus and species within the family Flavobacteriaceae, for which the name Sabulilitoribacter multivorans gen. nov., sp. nov. is proposed. The type strain of S. multivorans is M-M16(T) (= KCTC 32326(T) = CCUG 63831(T)).

Algibacter miyuki sp. nov., a member of the family Flavobacteriaceae isolated from leachate of a brown algae reservoir

A Gram-negative, aerobic, non-flagellated, non-gliding and rod-shaped bacterial strain, designated WS-MY6(T), was isolated from a brown algae reservoir in South Korea. Strain WS-MY6(T) grew optimally at 25 °C, at pH 7.0-8.0 and in the presence of 2 % (w/v) NaCl. Neighbour-joining, maximum-likelihood and maximum-parsimony phylogenetic trees based on 16S rRNA gene sequences showed that strain WS-MY6(T) clustered with the type strains of Algibacter lectus and 'Algibacter undariae', showing 16S rRNA gene sequence similarity values of 98.1 and 98.4 %, respectively. It exhibited sequence similarities of 95.4-96.7 % to the type strains of the other Algibacter species, Pontirhabdus pectinovorans and Marinivirga aestuarii, whose reclassification into the genus Algibacter has been recently proposed. Strain WS-MY6(T) contained MK-6 as the predominant menaquinone and iso-C15:1 G, anteiso-C15:0 and iso-C17:0 3-OH as the major fatty acids. It contained phosphatidylethanolamine and two unidentified lipids as the major polar lipids. The DNA G + C content of strain WS-MY6(T) was 35.3 mol% and its DNA-DNA relatedness values with A. lectus KCTC 12103(T) and 'A. undariae' WS-MY9(T) was 21 and 13 %, respectively. The phylogenetic and genetic distinctiveness and differential phenotypic properties revealed that strain WS-MY6(T) is separate from existing Algibacter species. On the basis of the data presented, strain WS-MY6(T) is considered to represent a novel species of the genus Algibacter, for which the name Algibacter miyuki sp. nov. is proposed. The type strain is WS-MY6(T) (=KCTC 32382(T) =CECT 8300(T)).

Marinivirga aestuarii gen. nov., sp. nov., a member of the family Flavobacteriaceae , isolated from marine environments, and emended descriptions of the genera Hyunsoonleella , Jejuia and Pontirhabdus and the species Hyunsoonleella jejuensis , Jejuia pallidilutea and Pontirhabdus pectinivorans

Two orange, rod-shaped, Gram-reaction-negative, aerobic bacterial strains devoid of flagella and gliding motility, designated strains KYW371T and KS18 were isolated from a seawater sample and a shellfish Ruditapes philippinarum, respectively, collected from Gwangyang Bay, Republic of Korea. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two strains belonged to the family Flavobacteriaceae ; and that strain KYW371T was most closely related to Algibacter mikhailovii LMG 23988T (96.7 % sequence similarity), Pontirhabdus pectinivorans JC2675T (96.3 %), Postechiella marina M091T (95.6 %) and Hyunsoonleella jejuensis CNU004T (95.3 %). The 16S rRNA gene sequence similarity (98.8 %) and DNA–DNA relatedness (78.1 %) between strains KYW371T and KS18 indicated that these two strains represented a single species. The predominant cellular fatty acids of strain KYW371T were iso-C15 : 1 G, iso-C15 : 0, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH. Flexirubin-type pigments were absent. MK-6 was the only isoprenoid quinone and the DNA G+C content was 34.8–36.6 mol%. Data from this taxonomic study employing a polyphasic approach suggested that the isolates represent a novel species in a new genus in the family Flavobacteriaceae , for which the name Marinivirga aestuarii gen. nov., sp. nov. is proposed. The type strain is KYW371T ( = KCTC 23449T = JCM 17452T), and an additional strain of the species is KS18 ( = KCTC 23128 = JCM 16845). Emended descriptions of the genera Hyunsoonleella , Jejuia and Pontirhabdus and the species Hyunsoonleella jejuensis , Jejuia pallidilutea and Pontirhabdus pectinivorans are also proposed.

Algibacter aquimarinus sp. nov., isolated from a marine environment, and reclassification of Pontirhabdus pectinivorans as Algibacter pectinivorans comb. nov

An orange-coloured, rod-shaped, Gram-reaction-negative and aerobic bacterial strain, designated KYW589(T), was isolated from seawater collected from Gwangyang Bay, Republic of Korea. The isolate required sea salts for growth. Gliding motility was observed. Flexirubin-type pigments were absent. Major cellular fatty acids (>10% of the total) were iso-C15:0, iso-C17:0 3-OH, iso-C15:1 G, C16:0, iso-C15:0 3-OH and C18:0. The main polar lipids were phosphatidylethanolamine, two unidentified aminolipids and two unidentified lipids. The predominant isoprenoid quinone was MK-6. The DNA G+C content was 38.6 ± 0.7 mol% (mean ± sd of three determinations). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain KYW589(T) belongs to the family Flavobacteriaceae, and was related to the genus Algibacter. Based on data from a study using a polyphasic taxonomic approach, it is proposed that strain KYW589(T) represents a novel species belonging to the genus Algibacter, for which the name Algibacter aquimarinus sp. nov. is proposed. The type strain is KYW589(T) (=KCTC 23928(T) =JCM 18287(T)). Reclassification of Pontirhabdus pectinivorans Yi et al. 2011 to the genus Algibacter, as Algibacter pectinivorans comb. nov. (type strain JC2675(T) =KACC 14153(T) =JCM 17107(T)), is also proposed.

Flavivirga jejuensis gen. nov., sp. nov., and Flavivirga amylovorans sp. nov., new members of the family Flavobacteriaceae isolated from seawater, and emended descriptions of the genera Psychroserpens and Lacinutrix

Two yellow, rod-shaped, Gram-reaction-negative, strictly aerobic bacterial strains, designated JC2682T and JC2681T, were isolated from a seawater sample of Jeju Island, Korea. The isolates required sea salts for growth and showed gliding motility. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strains JC2682T and JC2681T shared 96.9 % similarity and formed a robust monophyletic group within the radiation encompassing the family Flavobacteriaceae . This distinct clade, which had varying branch positions depending on the tree-making algorithm used, represents a new genus within the family Flavobacteriaceae . The predominant isoprenoid quinone (menaquinone 6, MK-6) and DNA G+C content (27–33 mol%) were consistent with its assignment to the family Flavobacteriaceae , but the polar lipid profile, fatty acid composition and overall phenotypic traits demonstrated that the test strains were not closely affiliated to any recognized genera. Based on data from the present polyphasic taxonomic study, strains JC2682T and JC2681T are considered to represent two novel species of a new genus in the family Flavobacteriaceae , for which the names Flavivirga jejuensis gen. nov., sp. nov. and Flavivirga amylovorans sp. nov. are proposed, respectively. The type strain of Flavivirga jejuensis is JC2682T ( = KACC 14158T  = JCM 17113T). The type strain of Flavivirga amylovorans is JC2681T ( = KACC 14157T  = JCM 17112T). Amended descriptions of the genera Psychroserpens and Lacinutrix are provided.

Pontirhabdus pectinivorans gen. nov., sp. nov., isolated from seawater

A yellow-coloured, rod-shaped, Gram-reaction-negative and aerobic bacterial strain, designated JC2675T, was isolated from a seawater sample from Jeju Island, Korea. The isolate required sea salts for growth. Gliding motility was observed. Flexirubin-type pigments were absent. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain JC2675T represented a distinct phyletic line that reflected a novel generic status within the family Flavobacteraceae with relatively low gene sequence similarities (<95.7 %) to other recognized genera. The predominant isoprenoid quinone (MK-6) and DNA G+C content (30 mol%) were consistent with the assignment of the novel strain to the family Flavobacteriaceae, but overall phenotypic traits demonstrated that the novel strain was not closely affiliated with any previously described genus. Based on data from a study using a polyphasic taxonomic approach, it is proposed that strain JC2675T represents a new genus and novel species belonging to the family Flavobacteriaceae, for which the name Pontirhabdus pectinivorans gen. nov., sp. nov. is proposed. The type strain of the type species is JC2675T ( = KACC 14153T = JCM 17107T).

Meridianimaribacter flavus gen. nov., sp. nov., a member of the family Flavobacteriaceae isolated from marine sediment of the South China Sea

A Gram-staining-negative, rod-shaped marine bacterium, designated strain NH57NT, isolated from sandy sediment in the Mischief Reef of the South China Sea, was characterized based on its physiological and biochemical features, fatty acid profile and phylogenetic position. 16S rRNA gene sequence analysis revealed a clear affiliation with the family Flavobacteriaceae. Strain NH57NT showed the closest phylogenetic relationship with members of the genera Gaetbulibacter, Gelidibacter, Subsaxibacter, Subsaximicrobium and Yeosuana; levels of 16S rRNA gene sequence similarity between strain NH57NT and the type strains of related species ranged from 94.9 to 91.2 %. Cells of strain NH57NT were motile by gliding and grew on solid media as yellow colonies at 9–37 °C, pH 6.5–8.5 and in the presence of 0.5–4.0 % NaCl. The DNA G+C content was 32.7 mol% and the predominant fatty acids were iso-C15 : 1 (22.7 % of the total), iso-C15 : 0 (20.7 %), iso-C17 : 0 3-OH (9.5 %), iso-C16 : 0 3-OH (8.3 %), C15 : 0 (7.8 %) and iso-C15 : 0 3-OH (5.8 %). Based on the physiological and phylogenetic data, and on the fatty acid composition, strain NH57NT is considered to represent a novel species of a new genus in the family Flavobacteriaceae, for which the name Meridianimaribacter flavus gen. nov., sp. nov. is proposed. The type strain of Meridianimaribacter flavus is NH57NT (=CCTCC AB 208318T=LMG 24839T=MCCC 1A03544T).

Mariniflexile fucanivorans sp. nov., a marine member of the Flavobacteriaceae that degrades sulphated fucans from brown algae

A rod-shaped, Gram-negative, chemo-organotrophic, heterotrophic, strictly aerobic, gliding bacterial strain, SW5(T), capable of degrading sulphated fucans from brown algae was isolated from a water-treatment facility that recycles the effluent of an alginate-extraction plant in Landerneau (Brittany, France). Its taxonomic position was investigated by a polyphasic approach. Strain SW5(T) formed dark-yellow colonies, was oxidase-negative and catalase-positive and grew optimally at 25 degrees C and pH 7.5 and in the presence of 2.5% (w/v) NaCl. The DNA G+C content was 34.5 mol%. Phylogenetic analysis based on the sequence of the 16S rRNA gene allocated strain SW5(T) to the genus Mariniflexile in the family Flavobacteriaceae, with a similarity of 98.4 % to the type strain of Mariniflexile gromovii, the only recognized Mariniflexile species. Its low level of DNA-DNA relatedness (<25%) with the type strain of this species and differentiating phenotypic characteristics demonstrated that strain SW5(T) constitutes a novel Mariniflexile species, for which the name Mariniflexile fucanivorans sp. nov. is proposed. Strain SW5(T) (=CIP 109502(T) =DSM 18792(T)) is the type strain.

Algibacter mikhailovii sp. nov., a novel marine bacterium of the family Flavobacteriaceae, and emended description of the genus Algibacter

A novel marine bacterium, designated strain KMM 6171(T), was subjected to taxonomic analysis by using a polyphasic approach. Colonies were yellow-pigmented and cells were Gram-negative, heterotrophic rods displaying slow gliding motility. 16S rRNA gene sequence analysis indicated that strain KMM 6171(T) was closely related to the genus Algibacter, a member of the family Flavobacteriaceae, with sequence similarity of 96.7-96.8 %. The predominant cellular fatty acids were iso-C15 : 1, iso-C15 : 0, anteiso-C15 : 0, C15 : 0, iso-C15 : 0 3-OH, iso-C17 : 0 3-OH and summed feature 3, comprising C16 : 1omega7c and/or iso-C15 : 0 2-OH. The DNA G+C content was 35.1 mol%. On the basis of the phenotypic, genotypic, chemotaxonomic and phylogenetic data, strain KMM 6171(T) represents a novel species of the genus Algibacter, for which the name Algibacter mikhailovii sp. nov. is proposed. The type strain is KMM 6171(T) (=KCTC 12710(T)=LMG 23988(T)). An emended description of the genus Algibacter based on the new data is also given.

Tamlana crocina gen. nov., sp. nov., a marine bacterium of the family Flavobacteriaceae, isolated from beach sediment in Korea

A Gram-negative, aerobic, saffron-coloured marine bacterium, designated HST1-43(T), was isolated from beach sediment on the coast in Jeju, Korea, and its taxonomic status was established in a polyphasic study. 16S rRNA gene sequence analyses revealed that the isolate belonged to the family Flavobacteriaceae. The closest phylogenetic neighbours of strain HST1-43(T) were members of the genera Algibacter, Gaetbulibacter and Yeosuana, with levels of sequence similarity in the range 96.3-96.5 %. The isolate was non-motile and required sea salts or natural seawater for growth. The optimum temperature and pH ranges for growth were 25-30 degrees C and pH 6.1-8.1, respectively. MK-6 was the major menaquinone. The dominant cellular fatty acids were iso-C(15 : 0), C(18 : 0), C(16 : 0), iso-C(15 : 1) and iso-C(17 : 0) 3-OH. The DNA G+C content was 36.2+/-0.4 mol%. On the basis of phylogenetic distance and phenotypic characteristics, the isolate is considered to represent a novel genus and species in the family Flavobacteriaceae, for which the name Tamlana crocina gen. nov., sp. nov. is proposed. The type strain is HST1-43(T) (=KCTC 12721(T)=JCM 14021(T)).

Mesoflavibacter zeaxanthinifaciens gen. nov., sp. nov., a novel zeaxanthin-producing marine bacterium of the family Flavobacteriaceae

A novel strictly aerobic, gliding, Gram-negative, rod-shaped, halo- and mesophilic bacterium (TD-ZX30(T)) was isolated from a seawater sample collected on the Pacific coastline of Japan near Kamakura City (Fujisawa, Kanagawa). The temperature range for growth of TD-ZX30(T) was between 16 and 44 degrees C. The DNA G+C content was 32.0mol%. The predominant fatty acids were iso-C(15:1) G, iso-C(15:0), iso-C(16:0) 3-OH, iso-C(15:0) 3-OH, Summed feature (iso-C(15:0) 2-OH and/or C(16:1)omega7c), iso-C(17:0) 3-OH, and C(15:0). MK-6 was the only respiratory quinone. Zeaxanthin was the major carotenoid pigment produced but flexirubin-type pigments were not produced. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that TD-ZX30(T) belonged to a distinct lineage in the family Flavobacteriaceae, sharing 93.9% sequence similarity with the nearest species Olleya marilimosa. TD-ZX30(T) could be distinguished from the other members of the family Flavobacteriaceae by a number of chemotaxonomic and phenotypic characteristics. The results of polyphasic taxonomic analyses suggested that TD-ZX30(T) represents a novel genus and a novel species, for which the name Mesoflavibacter zeaxanthinifaciens gen. nov., sp. nov. is proposed. The type strain is TD-ZX30(T) (=NBRC 102119=CCUG 53614=DSM 18436).

Zhouia amylolytica gen. nov., sp. nov., a novel member of the family Flavobacteriaceae isolated from sediment of the South China Sea

Three Gram-negative, non-spore-forming strains were isolated from sediment from the South China Sea, China, and their taxonomic positions were investigated using a polyphasic approach. Strains HN-171T, HN-172 and HN-181 grew optimally at 30 °C, in the presence of 4.5–5.0 NaCl % (w/v) and at pH 7.2–7.4. They contained MK-6 as the predominant respiratory quinone and contained iso-C15 : 1G, iso-C15 : 0, summed feature 4 (iso-C15 : 02-OH and/or C16 : 1ω7c/t) and C15 : 0as the major fatty acids. The DNA G+C content of strain HN-171Twas 34.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences demonstrated that strain HN-171T, together with strains HN-172 and HN-181, formed a distinct evolutionary lineage within the familyFlavobacteriaceae. The 16S rRNA gene sequences of strains HN-171T, HN-172 and HN-181 shared 99.8–100 % similarity with each other, and the sequence of strain HN-171Texhibited similarity values below 90.2 % with those of other members of the familyFlavobacteriaceae. The closest relative of HN-171TwasCoenonia anatinaLMG 14382T(90.2 %). On the basis of their phenotypic and phylogenetic properties, the three isolates represent a novel genus and a novel species, for which the nameZhouia amylolyticagen. nov., sp. nov. is proposed. The type strain is HN-171T(=CGMCC 1.6114T=JCM 14016T).

Flaviramulus basaltis gen. nov., sp. nov., a novel member of the family Flavobacteriaceae isolated from seafloor basalt

Four yellow-pigmented, Gram-negative, motile strains were isolated from the glassy rind of submarine basaltic lava from the Jan Mayen area of the Norwegian/Greenland Sea at a depth of 1300 m below sea level. The four strains had identical 16S rRNA gene sequences and were indistinguishable in all phenotypic and chemotypic tests performed, indicating that they belonged to the same species. The strains had an obligately aerobic chemo-organotrophic metabolism. The strains were capable of growth at temperatures between -2 and 34 degrees C, at pH between 6.5 and 8.6, and at sea salt concentrations between 3 and 60 g l(-1). The strains were able to utilize organic acids, amino acids and sugars but not alcohols; they were also capable of hydrolysing a wide range of macromolecules. The predominant fatty acids were 15 : 0 iso, 15 : 1 iso, 15 : 0 iso 3-OH and 17 : 0 iso 3-OH. The mean DNA G+C content of the strains was 31.4 mol%. 16S rRNA gene sequence analysis indicated that the strains were affiliated to the genera Gaetbulibacter and Algibacter. However, phenotypic characteristics, especially aerobic metabolism, suggested that the strains should be placed within a new genus. On the basis of the polyphasic characterization of the four strains, it is suggested that the strains be included in the family Flavobacteriaceae as representatives of a novel species in a new genus, for which the name Flaviramulus basaltis gen. nov., sp. nov. is proposed. The type strain is H35(T) (=CIP 109091(T)=DSM 18180(T)).

Psychroserpens mesophilus sp. nov., a mesophilic marine bacterium belonging to the family Flavobacteriaceae isolated from a young biofilm

A number of marine bacteria isolated from young biofilms were characterized as belonging to the family Flavobacteriaceae. The taxonomic characterization of strain KOPRI 13649T, which was isolated from an acrylic surface at the seashore at Gangneung, Korea, is reported here. The nearly complete 16S rRNA gene sequence of strain KOPRI 13649T was determined and was found to have a high level of similarity with that of Psychroserpens burtonensis (95.0-95.6 %). In addition, phylogenetic analysis and comparison with closely related strains confirmed that the strain represented a novel member of the genus Psychroserpens. The major respiratory quinone of strain KOPRI 13649T was MK-6 and the DNA G+C content was 29.8 mol%. The dominant fatty acid methyl esters were i-15 : 0, a-15 : 0, i-16 : 0, i-15 : 1omega10, 16 : 1omega7 and 15 : 0. Growth was observed at 10-34 degrees C (optimum 30 degrees C), at pH 6-9 (optimum 6.5-8.0) and with 0.5-4 % NaCl (optimum 1 %). On the basis of the polyphasic taxonomic evidence presented, strain KOPRI 13649T (=KCCM 42261T=JCM 13413T) should be classified as the type strain of a novel species in the genus Psychroserpens, for which the name Psychroserpens mesophilus sp. nov. is proposed.

Mariniflexile gromovii gen. nov., sp. nov., a gliding bacterium isolated from the sea urchin Strongylocentrotus intermedius

A marine bacterium, designated strain KMM 6038T, was subjected to taxonomic analysis via a polyphasic approach. Cells of the strain were heterotrophic, orange-pigmented, Gram-negative and motile by means of gliding. 16S rRNA gene sequence analysis indicated that strain KMM 6038T was closely related to the type species of the genera Algibacter and Yeosuana, members of the family Flavobacteriaceae, with sequence similarities of 93.8 and 93.6 % to the respective type strains. However, several chemotaxonomic and phenotypic characteristics, such as the cellular fatty acid profile (iso-C15 : 0, anteiso-C15 : 0, iso-C15 : 1, C15 : 0, C15 : 1 ω6c, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH) and the low G+C content of the DNA (35.7 mol%), indicated that the strain should be separated from these two genera. From the results of phenotypic, genotypic, chemotaxonomic and phylogenetic analyses, the bacterium should be classified as representing a novel genus and species, for which the name Mariniflexile gromovii gen. nov., sp. nov. is proposed. The type strain of Mariniflexile gromovii is KMM 6038T (=KCTC 12570T=LMG 22578T).

Sandarakinotalea sediminis gen. nov., sp. nov., a novel member of the family Flavobacteriaceae

Four Gram-negative, orange-coloured, aerobic, heterotrophic bacteria were isolated from sediment samples collected on the Pacific coast of Japan near the cities of Toyohashi and Katsuura. 16S rRNA gene sequence analysis indicated that these strains form a distinct lineage within the family Flavobacteriaceae. The four isolates shared 99.9–100 % 16S rRNA gene sequence similarity with each other and showed 88–90.9 % similarity with their neighbours in the family Flavobacteriaceae. The four strains also shared high DNA–DNA reassociation values of 67–99 % with each other. All the strains grew at 37 °C but not at 4 °C, and degraded gelatin, starch and DNA. The major fatty acids were i-C15 : 0, a-C15 : 0, i-C16 : 0 and i-C17 : 0 3-OH. However, two common fatty acids of members of the Flavobacteriaceae, i-C15 : 1 and a-C15 : 1, were absent in these strains. The DNA G+C contents of the four strains were in the range 35–37 mol%. On the basis of the polyphasic evidence, it was concluded that these strains should be classified as a novel genus and a novel species in the family Flavobacteriaceae, for which the name Sandarakinotalea sediminis gen. nov., sp. nov. is proposed. The type strain of Sandarakinotalea sediminis is CKA-5T (=NBRC 100970T=LMG 23247T).

Yeosuana aromativorans gen. nov., sp. nov., a mesophilic marine bacterium belonging to the family Flavobacteriaceae, isolated from estuarine sediment of the South Sea, Korea

A marine bacterium, GW1-1T, capable of degrading benzo[a]pyrene (BaP), was isolated from estuarine sediments of the South Sea (the Korea Strait), Korea, after an enrichment culture maintained for 2 years in a medium supplemented with a mixture of BaP and pyrene. The strain formed yellowish-brown colonies on marine agar 2216. Cells were strictly aerobic, non-motile, Gram-negative rods and produced non-diffusible carotenoid pigments. Optimal growth occurred in the presence of 1 % (w/v) NaCl and at pH 7 and 33–36 °C. No growth occurred without supplementation with either CaCl2 or MgCl2, even in the presence of NaCl. Phylogenetic analysis based on the nearly complete sequence of the 16S rRNA gene revealed that the isolate formed a phyletic lineage with the genera Gelidibacter (93·9–94·7 % gene sequence similarity), Subsaximicrobium (93·3 %) and Subsaxibacter (93·9 %). The isolate also showed high sequence similarities to Gaetbulibacter saemankumensis (94·5 %), Algibacter lectus (94·2 %), members of the genus Bizionia (93·6–94·3 %) and Formosa algae (93·2 %), even though it belonged to a different phyletic line. The major respiratory quinones of the isolate were menaquinones MK-5 and MK-6. The DNA G+C content was 51·4 mol%. Dominant fatty acids were i-15 : 0, a-15 : 0, i-15 : 1ω10c and 16 : 1. On the basis of this polyphasic taxonomic evidence, strain GW1-1T is classified as a member of a novel genus and species in the family Flavobacteriaceae, for which the name Yeosuana aromativorans gen. nov., sp. nov. is proposed. The type strain of the type species is GW1-1T (=KCCM 42019T=JCM 12862T).

Krokinobacter gen. nov., with three novel species, in the family Flavobacteriaceae

Five strains belonging to the family Flavobacteriaceae were isolated from marine-sediment samples collected in Sagami and Tokyo bays on the Pacific coastline of Japan. The five isolates formed a coherent and novel genus-level lineage within the family Flavobacteriaceae. The most closely related species with a validly published name was Cellulophaga lytica. The five isolates were rod-shaped, Gram-negative, aerobic, catalase- and oxidase-positive, flexirubin-negative and yellow-pigmented. The dominant fatty acids were branched or hydroxy acids, i.e. i-C15 : 0, i-C15 : 1 and i-C17 : 0 3-OH. These strains degraded gelatin, casein, DNA and Tween 80. The G+C content of their DNAs ranged between 33 and 39 mol%. Although analysis of the 16S rRNA gene sequence similarity divided these strains into two subgroups with a 2·3 % sequence difference, the results of DNA–DNA hybridization indicated the grouping of these strains into three distinct species. On the basis of phenotypic and genotypic analyses, the novel genus Krokinobacter is proposed, with Krokinobacter genikus sp. nov., containing three of the strains, as the type species. The type strain is Cos-13T (=NBRC 100811T=CIP 108744T). The names Krokinobacter eikastus sp. nov. (type strain PMA-26T=NBRC 100814T=CIP 108743T) and Krokinobacter diaphorus sp. nov. (type strain MSKK-32T=NBRC 100817T=CIP 108745T) are proposed for the other two isolates.