Aestuariibacter salexigens gen. nov., sp. nov. and Aestuariibacter halophilus sp. nov., isolated from tidal flat sediment, and emended description of Alteromonas macleodii

Bioplastic degradation and assimilation processes by a novel bacterium isolated from the marine plastisphere

Biosourced and biodegradable plastics offer a promising solution to reduce environmental impacts of plastics for specific applications. Here, we report a novel bacterium named Alteromonas plasticoclasticus MED1 isolated from the marine plastisphere that forms biofilms on foils of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). Experiments of degradation halo, plastic matrix weight loss, bacterial oxygen consumption and heterotrophic biosynthetic activity showed that the bacterial isolate MED1 is able to degrade PHBV and to use it as carbon and energy source. The likely entire metabolic pathway specifically expressed by this bacterium grown on PHBV matrices was shown by further genomic and transcriptomic analysis. In addition to a gene coding for a probable secreted depolymerase, a gene cluster was located that encodes characteristic enzymes involved in the complete depolymerization of PHBV, the transport of oligomers, and in the conversion of the monomers into intermediates of central carbon metabolism. The transcriptomic experiments showed the activation of the glyoxylate shunt during PHBV degradation, setting the isocitrate dehydrogenase activity as regulated branching point of the carbon flow entering the tricarboxylic acid cycle. Our study also shows the potential of exploring the natural plastisphere to discover new bacteria with promising metabolic capabilities.

Fluctibacter corallii gen. nov., sp. nov., isolated from the coral Montipora capitata on a reef in Kāne'ohe Bay, O'ahu, Hawai'i, reclassification of Aestuariibacter halophilus as Fluctibacter halophilus comb. nov., and Paraglaciecola oceanifecundans as a later heterotypic synonym of Paraglaciecola agarilytica

Strain AA17T was isolated from an apparently healthy fragment of Montipora capitata coral from the reef surrounding Moku o Lo'e in Kāne'ohe Bay, O'ahu, Hawai'i, USA, and was taxonomically evaluated using a polyphasic approach. Comparison of a partial 16S rRNA gene sequence found that strain AA17T shared the greatest similarity with Aestuariibacter halophilus JC2043T (96.6%), and phylogenies based on 16S rRNA gene sequences grouped strain AA17T with members of the Aliiglaciecola, Aestuariibacter, Lacimicrobium, Marisediminitalea, Planctobacterium, and Saliniradius genera. To more precisely infer the taxonomy of strain AA17T, a phylogenomic analysis was conducted and indicated that strain AA17T formed a monophyletic clade with A. halophilus JC2043T, divergent from Aestuariibacter salexigens JC2042T and other related genera. As a result of monophyly and multiple genomic metrics of genus demarcation, strain AA17T and A. halophilus JC2043T comprise a distinct genus for which the name Fluctibacter gen. nov. is proposed. Based on a polyphasic characterisation and identifying differences in genomic and taxonomic data, strain AA17T represents a novel species, for which the name Fluctibacter corallii sp. nov. is proposed. The type strain is AA17T (= LMG 32603 T = NCTC 14664T). This work also supports the reclassification of A. halophilus as Fluctibacter halophilus comb. nov., which is the type species of the Fluctibacter genus. Genomic analyses also support the reclassification of Paraglaciecola oceanifecundans as a later heterotypic synonym of Paraglaciecola agarilytica.

Marine Bacterioplankton Community Dynamics and Potentially Pathogenic Bacteria in Seawater around Jeju Island, South Korea, via Metabarcoding

Understanding marine bacterioplankton composition and distribution is necessary for improving predictions of ecosystem responses to environmental change. Here, we used 16S rRNA metabarcoding to investigate marine bacterioplankton diversity and identify potential pathogenic bacteria in seawater samples collected in March, May, September, and December 2013 from two sites near Jeju Island, South Korea. We identified 1343 operational taxonomic units (OTUs) and observed that community diversity varied between months. Alpha- and Gamma-proteobacteria were the most abundant classes, and in all months, the predominant genera were Candidatus Pelagibacter, Leisingera, and Citromicrobium. The highest number of OTUs was observed in September, and Vibrio (7.80%), Pseudoalteromonas (6.53%), and Citromicrobium (6.16%) showed higher relative abundances or were detected only in this month. Water temperature and salinity significantly affected bacterial distribution, and these conditions, characteristic of September, were adverse for Aestuariibacter but favored Citromicrobium. Potentially pathogenic bacteria, among which Vibrio (28 OTUs) and Pseudoalteromonas (six OTUs) were the most abundant in September, were detected in 49 OTUs, and their abundances were significantly correlated with water temperature, increasing rapidly in September, the warmest month. These findings suggest that monthly temperature and salinity variations affect marine bacterioplankton diversity and potential pathogen abundance.

Paraneptunicella aestuarii gen. nov., sp. nov., a member of the family Alteromonadaceae isolated from seawater in East China Sea

An aerobic Gram-stain-negative, curved rod-shaped and non-spore-forming bacterial strain (NBU2194^T) was isolated from seawater collected in an intertidal zone in Ningbo, Zhejiang Province, PR China. It was motile though a single polar flagellum and grew at 20-42 °C (optimum, 30 °C), in 0-2.0 % NaCl (0 %, w/v) and at pH 5.0-9.0 (pH 6.0-7.0). The sole respiratory quinone was ubiquinone-8. The major cellular fatty acids were C_16 : 0, C_16 : 1  ω7c and/or C_16 : 1  ω6c. The polar lipids contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified phospholipid and two unidentified aminophosphoglycolipids. A phylogenetic analysis based on 16S rRNA gene sequences and 65 genomic core genes showed that strain NBU2194^T formed a distinct lineage in the family Alteromonadaceae. The genome of strain NBU2194^T was 4 913 533 bp with a DNA G+C content of 43.9 mol% and coded 3895 genes, 12 rRNA genes and 47 tRNA genes. The average nucleotide identity, amino acid identity and digital DNA-DNA hybridization values between strain NBU2194^T and related species of Alteromonadaceae were below the threshold limit for prokaryotic species delineation. NBU2194^T could be distinguished from other genera in the family Alteromonadaceae based on phenotypic, chemotaxonomic and genomic characteristics. On the basis of the polyphasic taxonomic evidence collected in this study, strain NBU2194^T is considered to represent a novel genus and species in the family Alteromonadaceae, for which the name Paraneptunicella aestuarii is proposed. The type strain is NBU2194^T (=KCTC 82442^T=GDMCC 1.2217^T).

Draft Genome Sequence of Aestuariibacter halophilus Type Strain JC2043

Aestuariibacter halophilus strain JC2043, a Gram-negative gammaproteobacterium, is often used as a reference organism for assigning taxonomy within the family Alteromonadaceae. Isolates of this species have also been investigated for compound degradation (e.g., phthalates and oil) and biofilm association. Presented here is the draft genome sequence of A. halophilus strain JC2043.

Potential lineage transmission within the active microbiota of the eggs and the nauplii of the shrimp Litopenaeus stylirostris: possible influence of the rearing water and more

BACKGROUND

Microbial communities associated with animals are known to be key elements in the development of their hosts. In marine environments, these communities are largely under the influence of the surrounding water. In aquaculture, understanding the interactions existing between the microbiotas of farmed species and their rearing environment could help establish precise bacterial management.

METHOD

In light of these facts, we studied the active microbial communities associated with the eggs and the nauplii of the Pacific blue shrimp (Litopenaeus stylirostris) and their rearing water. All samples were collected in September 2018, November 2018 and February 2019. After RNA extractions, two distinct Illumina HiSeq sequencings were performed. Due to different sequencing depths and in order to compare samples, data were normalized using the Count Per Million method.

RESULTS

We found a core microbiota made of taxa related to Aestuariibacter, Alteromonas, Vibrio, SAR11, HIMB11, AEGEAN 169 marine group and Candidatus Endobugula associated with all the samples indicating that these bacterial communities could be transferred from the water to the animals. We also highlighted specific bacterial taxa in the eggs and the nauplii affiliated to Pseudomonas, Corynebacterium, Acinetobacter, Labrenzia, Rothia, Thalassolituus, Marinobacter, Aureispira, Oleiphilus, Profundimonas and Marinobacterium genera suggesting a possible prokaryotic vertical transmission from the breeders to their offspring. This study is the first to focus on the active microbiota associated with early developmental stages of a farmed shrimp species and could serve as a basis to comprehend the microbial interactions involved throughout the whole rearing process.

Ningiella ruwaisensis gen. nov., sp. nov., a member of the family Alteromonadaceae isolated from marine water of the Arabian Gulf

Strain B66^T was isolated from a marine water sample collected at Al Ruwais, located on the northern tip of Qatar. Cells were Gram-stain-negative, strictly aerobic and short- rod-shaped with a polar flagellum. The isolate was able to grow at 15-45 °C (optimum, 30 °C), at pH 5-11 (optimum, pH 6.5-8) and with 0-6 % NaCl. 16S rRNA gene sequence analysis revealed that strain B66^T was affiliated with the family Alteromonadaceae, sharing the highest sequence similarities to the genera Alteromonas (93.7-95.4 %), Aestuariibacter (94.0-95.1 %), Agaribacter (93.3-93.7 %), Glaciecola (92.0-93.7 %), Marisendiminitalea (93.2-93.3 %) and Planctobacterium (92.9 %). In the phylogenetic trees, strain B66^T demonstrated the novel organism formed a distinct lineage closely associated with Aestuariibacter and Planctobacterium. Major fatty acids were C_16 : 0, summed feature 3 (C_16 : 1  ω7c/C_16 : 1  ω6c/iso-C_15 : 0 2-OH and iso-C_15 : 0 3-OH. The major respiratory quinone was ubiquinone-8 and the major polar lipids are phosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content derived from the genome was 43.2 mol%. Based on the phenotypic, chemotaxonomic, phylogenetic and genomic data, strain B66^T is considered to represent a novel species and genus for which the name Ningiella ruwaisensis gen. nov., sp. nov., is proposed. The type strain is B66^T (=QCC B003/17^T=LMG 30288 ^T=CCUG 70703^T).

Alteromonas portus sp. nov., an alginate lyase-excreting marine bacterium

An alginate lyase-excreting bacterium, designated strain HB161718T, was isolated from coastal sand collected from Tanmen Port in Hainan, PR China. Cells were Gram-stain-negative rods and motile with a single polar flagellum. Its major isoprenoid quinone was ubiquinone 8 (Q-8), and its cellular fatty acid profile mainly consisted of C16 : 1 ω7c and/or C16 : 1 ω6c, C18 : 1 ω6c and/or C18 : 1 ω7c, C16 : 0, C17 : 0 10-methyl and C16 : 0 N alcohol. The G+C content of the genomic DNA was 44.1 mol%. 16S rRNA gene sequence analysis suggested that strain HB161718T belonged to the genus Alteromonas , sharing 99.5, 99.4, 99.2, 98.9 and 98.5 % sequence similarities to its closest relatives, Alteromonas macleodii JCM 20772T, Alteromonas gracilis 9a2T, Alteromonas australica H17T, Alteromonas marina SW-47T and Alteromonas mediterranea DET, respectively. The low values of DNA–DNA hybridization and average nucleotide identity showed that it formed a distinct genomic species. The combined phenotypic and molecular features supported the conclusion that strain HB161718T represents a novel species of the genus Alteromonas , for which the name Alteromonas portus sp. nov. is proposed. The type strain is HB161718T (=CGMCC 1.13585T=JCM 32687T).

Marisediminitalea mangrovi gen. nov., sp. nov., isolated from marine mangrove sediment, and reclassification of Aestuariibacter aggregatus as Marisediminitalea aggregata comb. nov

Strain GS-14^T was isolated from a mangrove sediment sample collected at Beilun Estuary National Nature Reserve, Guangxi Province, PR China. Cells were Gram-stain-negative, strictly aerobic and rod-shaped with a polar flagellum. Optimal growth occurred in the presence of 3-6 % (w/v) NaCl, at pH 6-8 and at a temperature of 37 °C. The predominant polar lipids were phosphatidylglycerol and phosphatidylethanolamine. Ubiquinone 8 (Q-8) was the sole respiratory quinone. The major fatty acids (>10 % of the total fatty acids) were summed feature 3 (C_16 : 1ω7c and/or C_16 : 1ω6c) and C_16 : 0. The DNA G+C content was 47.6 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain GS-14^T had the highest sequence similarity to Aestuariibacter aggregatus WH169^T (96.63 %), Aliiglaciecola coringensis AK49^T (96.56 %) and Alteromonas lipolytica JW12^T (96.22 %). In addition, the OrthoANIu value and dDDH values calculated from the genomes of strain GS-14^T and A. aggregatus WH169^T were 79.5 and 21.9 %, respectively. Based on the polyphasic taxonomic results, strain GS-14^T is considered to represent a novel species in a new genus, for which the name Marisediminitalea mangrovi gen. nov., sp. nov. is proposed. The type strain of Marisediminitalea mangrovi is GS-14^T (=KCTC 72401^T=MCCC 1K03622^T). Because Aestuariibacter aggregatus WH169^T clustered with strain GS-14^T in the phylogenetic trees and was clearly separated from the two species within the genus Aestuariibacter, it is reclassified as a member of the genus Marisediminitalea as Marisediminitalea aggregata comb. nov. (type strain WH169^T=CGMCC 1.8995^T=LMG 25283^T). The type species of the genus Marisediminitalea is Marisediminitalea aggregata gen. nov., comb. nov.

Saliniradius amylolyticus gen. nov., sp. nov., isolated from solar saltern sediment

A novel non-pigmented, Gram-stain-negative, motile by means of a polar flagellum, aerobic and rod-shaped bacterium, designated HMF8227^T, was isolated from solar saltern sediment sampled at Shinan, Republic of Korea. The isolate was able to grow at 15-42 °C (optimum, 37 °C), at pH 6-8 (pH 7) and with 0.5-12 % NaCl (2-5 %). Strain HMF8227^T was positive for hydrolysis of starch and dextrin. 16S rRNA gene sequence analysis revealed that strain HMF8227^T was affiliated with the family Alteromonadaceae, sharing the highest sequence similarities to the genera Salinimonas (93.0-94.4 %), Aestuariibacter (92.0-94.2 %), Alteromonas (92.0-93.6 %) and Lacimicrobium (93.6 %). In the phylogenetic trees, strain HMF8227^T formed an independent clade with Lacimicrobium alkaliphilum X13M-12^T. The major fatty acids were C_16 : 0, summed feature 3 (C_16 : 1 ω7c and/or C_16 : 1 ω6c) and summed feature 8 (C_18 : 1 ω7c and/or C_18 : 1 ω6c). The major respiratory quinone was ubiquinone-8 (Q-8). The major polar lipids are phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid and two unidentified glycolipids. The DNA G+C content of the genomic DNA was 52.1 mol%. On the basis of the polyphasic characterizations, strain HMF8227^T represents a novel species and genus within the family Alteromonadaceae, for which the name Saliniradius amylolyticus gen. nov., sp. nov. is proposed, with the type strain being HMF8227^T (=KCTC 62462^T =NBRC 113230^T).

Effects of water recirculation rate on the microbial community and water quality in relation to the growth and survival of white shrimp (Litopenaeus vannamei)

Background

Microbial community and its management are crucial to the stabilization of culture environment for recirculating aquaculture system (RAS). Although several studies have been carried out for the microbial community of RAS, few studies were on the RAS for shrimp. Water recirculation ratio is an important factor for the microbial community and the management of RAS. Therefore, low (LC), medium (MC) and high (HC) recirculation ratio systems were set to explore the microbial community constitution of RAS for Litopenaeus vannamei and study the effect of water recirculation rate on it.

Results

The bacterial community of bioreactor was mainly dominated by Proteobacteria (41.6–70.7%), followed with Planctomycetes (12.5–31.0%), Bacteroidetes (10.5–26.0%), Actinobacteria (1.1–4.8%) and Verrucomicrobia (1.4–6.8%) phylum. The most dominant family of bioreactor was Rhodobacteraceae or Planctomycetaceae. The bacterial community of culture water was simpler than bioreactor and dominated by Proteobacteria (61.8–96.4%). The dominant bacterial groups of bioreactor and culture water are also different among the three water recirculation rates, and the proportions of dominant groups showed a trend with the variety of water recirculation rate. Water quality indexes including ammonia and nitrite decreased with the increasing of water recirculation rate. According to the growth performance of L. vannamei, shrimp had better performance of growth rate and final weight in MC and HC, however, shrimp had higher survival and yield in LC. Shrimp survival and yield had an inverse correlation with water recirculation rate.

Conclusions

The results demonstrate the microbial community of RAS for shrimp, highlight the importance of further studies on the function of bacterial taxa, and promote the understanding of the effects of water recirculation rate on the microbiota. The findings suggest that water recirculation rate has important impacts on the microbial community, water quality and shrimp growth. Increasing the water recirculation rate could improve the water quality and promote the growth of shrimp. However, the survival rate and yield of L. vannamei are higher under low water recirculation rate. Recirculation rate is an effective method to manage RAS, and its impact on RAS needs further study, especially in the application of low level of water recirculation.

Hydrocarboniclastica marina gen. nov., sp. nov., a marine hydrocarbonoclastic bacterium isolated from an in situ enriched hydrocarbon-degrading consortium in sea sediment

A Gram-stain-negative, motile, non-spore-forming, aerobic and rod-shaped bacterial strain, Soil36-7^T, was isolated from an in situ enriched hydrocarbon-degrading consortium in South China Sea sediment. Strain Soil36-7^T grew at 4-40 °C (optimum 28-32 °C), at pH 5-10 (pH 7-8) and in the presence of 1-12 % (w/v) NaCl (3-6 %). Phylogenetic analyses based on 16S rRNA gene sequences and a genome-based approach using UBCGs (up-to-date bacterial core genes) showed Soil36-7^T formed a distinct branching lineage within the family Alteromonadaceae. 16S rRNA gene sequence similarity was 92.9, 92.1 and >88.3 % between strain Soil36-7^T and the type species of the genera Marinobacter, Tamilnaduibacter and the other genera of the family Alteromonadaceae, respectively. The major fatty acids in Soil36-7^T were C16 : 0, C16 : 1ω6/7c, C16 : 0 10-methyl, C18 : 1ω7c, C12 : 0 and C18 : 0. The predominant respiratory quinone was Q-9, with a minor amount of Q-10 (3.5 %). The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and various unidentified glycolipids, phospholipids, aminophospholipids and other polar lipids. The DNA G+C content was 57.9 mol%. On the basis of phylogenetic, genomic, phenotypic and chemotaxanomic characteristics, strain Soil36-7^T could be classified as representing a novel species of a new genus within the family Alteromonadaceae, for which the name Hydrocarboniclastica marina gen. nov., sp. nov. is proposed. The type strain of the type species is Soil36-7^T (=MCCC 1A12105^T=KCTC 62334^T).

Neptunicella marina gen. nov., sp. nov., isolated from surface seawater

A Gram-stain-negative, aerobic, short rod-shaped bacterium with a single polar flagellum, designated strain S27-2^T, was isolated from surface seawater from the Indian Ocean. Growth was observed in 0-12.0 % (w/v) NaCl with an optimum of 0.5-2.0 % (w/v) NaCl, pH 6.0-9.0 with an optimum of pH 7.0, and growth temperature of 10-41 °C with an optimum of 25-37 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain S27-2^T belonged to the family Alteromonadaceae and formed a distinct lineage with the type strain of Pseudobowmanella zhangzhouensis. Levels of 16S rRNA gene sequence similarity between strain S27-2^T and members of related genera included in the trees ranged from 86.7 to 93.8 %. Strain S27-2^T contained Q-8 as the predominant ubiquinone. The principal fatty acids (>10 %) were C16 : 0 (22.1 %), C16 : 1ω7c/ω6c (22.7 %) and C18 : 1ω7c/ω6c (20.1 %). The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified phospholipid and two unknown lipids. The G+C content of strain S27-2^T was 43.7 mol%. On the basis of the polyphasic taxonomic evidence presented in this study, strain S27-2^T should be classified as a novel species in a new genus within the family Alteromonadaceae, for which the name Neptunicella marina gen. nov., sp. nov. is proposed, with the type strain S27-2^T (= KCTC52335^T=MCCC 1A02149^T).

Planctobacterium marinum gen. nov., sp. nov., a new member of the family Alteromonadaceae isolated from seawater

A bacterial strain designated K7T was isolated from the South China Sea and characterized using a polyphasic taxonomic approach. Cells of strain K7T were Gram-stain-negative, aerobic, poly-β-hydroxybutyrate-accumulating, motile by means of a monopolar flagellum, non-spore forming rods surrounded by a thick capsule and forming yellow colonies. Growth occurred at 4-35 °C (optimum, 25-30 °C), at pH 5.0-9.0 (optimum, pH 7.0) and with 0.5-10 % (w/v) NaCl [optimum, 1-4 % (w/v)]. The predominant fatty acids were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and C18 : 1ω7c. The major isoprenoid quinone was Q-8 and the DNA G+C content was 46.5 mol%. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylmonomethylethanolamine, one uncharacterized phospholipid, two uncharacterized aminophospholipids and five uncharacterized lipids. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain K7T formed a distinct lineage with respect to closely related genera in the family Alteromonadaceae. Strain K7T was most closely related to Aestuariibacter, Aliiglaciecola, Paraglaciecola and Glaciecola, and the levels of 16S rRNA gene sequence similarity with respect to the type species of related genera were less than 95 %. On the basis of the genotypic and phenotypic data, strain K7T represents a novel species of a new genus of the family Alteromonadaceae, for which the name Planctobacterium marinum gen. nov., sp. nov. is proposed. The type strain of Planctobacterium marinum is K7T (=BCRC 80901T=LMG 28835T=KCTC 42657T).

Tamilnaduibacter salinus gen. nov., sp. nov., a halotolerant gammaproteobacterium within the family Alteromonadaceae, isolated from a salt pan in Tamilnadu, India

Two novel Gram-stain-negative, slow-growing, halotolerant strains with rod-shaped cells, designated as strains Mi-7T and Mi-8, which formed pin-point colonies on halophilic media were isolated during a study into the microbial diversity of a salt pan in the state of Tamilnadu, India. Both the strains had an obligate requirement for 1 % (w/v) NaCl for growth and were halotolerant, growing at NaCl concentrations of up to 20 % (w/v) in media. The strains, however, showed an inability to utilize the majority of substrates tested as sole carbon sources for growth and in fermentation reactions. Molecular phylogenetic analyses, based on 16S rRNA gene sequence revealed their closest phylogenetic neighbours to be members of the genus Marinobacter, with whom they showed the highest sequence similarity of 93.6 % and even less with the type strain of the type species, Marinobacter hydrocarbonoclasticus DSM 8798T (91.1 %). Similarities with other genera within the family Alteromonadaceae were below 91.0 %. However, the two strains were very closely related to each other with 99.9 % sequence similarity, and DNA–DNA hybridization analyses confirmed their placement in the same species. The DNA G+C content of both strains was 65 mol%. Using the polyphasic taxonomic data obtained from this study, strains Mi-7T and Mi-8 represent two strains of the same species of a novel genus for which the name Tamilnaduibacter salinus gen. nov., sp. nov., is proposed; the type strain of the novel species is Mi-7T ( = MTCC 12009T = DSM 28688T).

Catenovulum maritimus sp. nov., a novel agarolytic gammaproteobacterium isolated from the marine alga Porphyra yezoensis Ueda (AST58-103), and emended description of the genus Catenovulum

A novel agarolytic, Gram-stain negative, heterotrophic, facultatively anaerobic and pale-white pigmented bacterial strain, designated Q1(T), was isolated from the marine alga Porphyra yezoensis Ueda (AST58-103) collected from the coastal area of Weihai, China. The cells are motile by means of peritrichous flagella. The isolate requires NaCl for growth, while seawater is not necessary, and growth occurs optimally at about 30-33 °C, in 1-3 % (w/v) NaCl and at pH 7-7.5. Strain Q1(T) shows oxidase-positive and catalase-negative activities, and possesses the ability to hydrolyse starch and alginate, but not cellulose, gelatin, urea or Tween-80. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain Q1(T) is affiliated with the family Alteromonadaceae within the class Gammaproteobacteria. The isolate, strain Q1(T), is most closely related to Catenovulum agarivorans YM01(T) (94.85 %), with less than 91.2 % sequence similarity to other close relatives with validly published names. The draft genome sequence of strain Q1(T) consists of 62 contigs (>200 bp) of 4,548,270 bp. The genomes of Q1(T) and YM01(T) have an ANI value of 70.7 %, and the POCP value between the two genomes is 64.4 %. The genomic DNA G+C content of strain Q1(T) is 37.9 mol% as calculated from the draft genome sequence. The main isoprenoid quinone is ubiquinone-8. The predominant cellular fatty acids are summed feature 3 (C16:1 ω7c and/or iso-C15:0 2-OH), C16:0 and C18:1 ω7c. The major polar lipids are phosphatidylethanolamine and phosphatidylglycerol. Based on data from a polyphasic chemotaxonomic, physiological and biochemical study, strain Q1(T) should be classified as a novel species of the genus Catenovulum, for which the name Catenovulum maritimus sp. nov. is proposed. The type strain is Q1(T) (=CICC 10836(T)=DSM 28813(T)).

Pseudobowmanella zhangzhouensis gen. nov., sp. nov., isolated from the surface freshwater of the Jiulong River in China

A strain, JS7-9(T), which was isolated from the surface freshwater of the Jiulong River, China, was subjected to taxonomic study. The bacterium was Gram-negative, facultatively anaerobic, rod-shaped and motile by means of a single polar flagellum. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JS7-9(T) is affiliated to the family Alteromonadaceae, showing 90.5-94.2 % of 16S rRNA gene sequence similarity with the genera Bowmanella (94.0-94.2 %), Aestuariibacter (93.0-93.5 %), Glaciecola (91.0-93.1 %), Alteromonas (90.5-93.1 %) and Salinimonas (90.6-91.8 %). The major fatty acids were identified as C16:0, Sum In Feature 3 (C16:1 ω7c/ω6c), Sum In Feature 8 (C18:1 ω7c/ω6c) and C17:1 ω8c, and Q-8 as the predominant isoprenoid quinone. Based on the phenotypic, chemotaxonomic and phylogenetic distinctiveness, strain JS7-9(T) is considered to represent a novel species of a novel genus of the family Alteromonadaceae, for which the name Pseudobowmanella zhangzhouensis gen. nov., sp. nov. is proposed, with the type strain JS7-9(T) (=MCCC 1A00758(T) = KCTC 42143(T)).

Phylogenetic analyses of the genus Glaciecola: emended description of the genus Glaciecola, transfer of Glaciecola mesophila, G. agarilytica, G. aquimarina, G. arctica, G. chathamensis, G. polaris and G. psychrophila to the genus Paraglaciecola gen. nov. as Paraglaciecola mesophila comb. nov., P. agarilytica comb. nov., P. aquimarina comb. nov., P. arctica comb. nov., P. chathamensis comb. nov., P. polaris comb. nov. and P. psychrophila comb. nov., and description of Paraglaciecola oceanifecundans sp. nov., isolated from the Southern Ocean

Phylogenetic analyses of the genus Glaciecola were performed using the sequences of the 16S rRNA gene and the GyrB protein to establish its taxonomic status. The results indicated a consistent clustering of the genus Glaciecola into two clades, with significant bootstrap values, with all the phylogenetic methods employed. Clade 1 was represented by seven species, Glaciecola agarilytica, G. aquimarina, G. arctica, G. chathamensis, G. mesophila, G. polaris and G. psychrophila, while clade 2 consisted of only three species, Glaciecola nitratireducens, G. pallidula and G. punicea. Evolutionary distances between species of clades 1 and 2, based on 16S rRNA gene and GyrB protein sequences, ranged from 93.0 to 95.0 % and 69.0 to 73.0 %, respectively. In addition, clades 1 and 2 possessed 18 unique signature nucleotides, at positions 132, 184 : 193, 185 : 192, 230, 616 : 624, 631, 632, 633, 738, 829, 1257, 1265, 1281, 1356 and 1366, in the 16S rRNA gene sequence and can be differentiated by the occurrence of a 15 nt signature motif 5'-CAAATCAGAATGTTG at positions 1354-1368 in members of clade 2. Robust clustering of the genus Glaciecola into two clades based on analysis of 16S rRNA gene and GyrB protein sequences, 16S rRNA gene sequence similarity of ≤95.0 % and the occurrence of signature nucleotides and signature motifs in the 16S rRNA gene suggested that the genus should be split into two genera. The genus Paraglaciecola gen. nov. is therefore created to accommodate the seven species of clade 1, while the name Glaciecola sensu stricto is retained to represent species of clade 2. The species of clade 1 are transferred to the genus Paraglaciecola as Paraglaciecola mesophila comb. nov. (type strain DSM 15026(T) = KMM 241(T)), P. agarilytica comb. nov. (type strain NO2(T) = KCTC 12755(T) = LMG 23762(T)), P. aquimarina comb. nov. (type strain GGW-M5(T) = KCTC 32108(T) = CCUG 62918(T)), P. arctica comb. nov. (type strain BSs20135(T) = CCTCC AB 209161(T) = KACC 14537(T)), P. chathamensis comb. nov. (type strain E3(T) = CGMCC 1.7001(T) = JCM 15139(T)), P. polaris comb. nov. (type strain ARK 150(T) = CIP 108324(T) = LMG 21857(T)) and P. psychrophila comb. nov. (type strain 170(T) = CGMCC1.6130(T) = JCM 13954(T)). The type species of the genus Paraglaciecola is Paraglaciecola mesophila. An emended description of the genus Glaciecola is provided. In addition, a novel strain, 162Z-12(T), was isolated from seawater collected as part of an iron fertilization experiment (LOHAFEX) conducted in the Southern Ocean in 2009 and was subjected to polyphasic taxonomic characterization. Cells of 162Z-12(T) were Gram-negative, aerobic, motile, ovoid to short rod-shaped, obligatorily halophilic and possessed all the characteristics of the genus Paraglaciecola. Strain 162Z-12(T) shared the highest 16S rRNA gene sequence similarity with the type strains of P. agarilytica (99.7 %), P. chathamensis (99.7 %), P. mesophila (98.5 %) and P. polaris (98.3 %). However, it exhibited DNA-DNA relatedness of less than 70.0 % with its nearest phylogenetic relatives, well below the threshold value for species delineation. Further, strain 162Z-12(T) differed from the nearest species in several phenotypic characteristics, in addition to the occurrence of unique nucleotides G, T, T and T at positions 1194, 1269, 1270 and 1271 of the 16S rRNA gene. Based on the cumulative differences it exhibited from its nearest phylogenetic neighbours, strain 162Z-12(T) was identified as a novel member of the genus Paraglaciecola and assigned to the novel species Paraglaciecola oceanifecundans sp. nov. The type strain of Paraglaciecola oceanifecundans is 162Z-12(T) ( = KCTC 32337(T) = LMG 27453(T)).

Agaribacter marinus gen. nov., sp. nov., an agar-degrading bacterium from surface seawater

A Gram-stain-negative, motile, mesophilic, aerobic, rod-shaped bacterium, strain 8-8(T), was isolated from surface seawater at Muroto, Kochi, Japan. The strain exhibited agar-degrading activity. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain fell within the family Alteromonadaceae and clustered distantly with members of the genus Glaciecola (≤ 94.0% similarity). The DNA G+C content was 41.8 mol%. The major fatty acids were C16 : 1ω7c and/or iso-C15 : 0 2-OH, C16 : 0 and C18 : 1ω7c and the major hydroxy fatty acid was C12 : 0 3-OH. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol and an unidentified polar lipid; lysophosphatidylethanolamine and unidentified polar lipids were found as minor components. The major quinone was Q-8. On the basis of phenotypic, genotypic and chemotaxonomic data, strain 8-8(T) represents a novel species of a new genus, for which the name Agaribacter marinus gen. nov., sp. nov. is proposed. The type strain of Agaribacter marinus is 8-8(T) ( = NBRC 110023(T) = LMG 28167(T)).

Reclassification of [Glaciecola] lipolytica and [ Aestuariibacter] litoralis in Aliiglaciecola gen. nov., as Aliiglaciecola lipolytica comb. nov. and Aliiglaciecola litoralis comb. nov., respectively

Following phylogenetic analysis based on 16S rRNA gene sequences, together with DNA G+C contents and differential chemotaxonomic and physiological characteristics, a new genus with the name Aliiglaciecola gen. nov. is proposed to more appropriately accommodate two recognized species of the genera Glaciecola and Aestuariibacter . Accordingly, [Glaciecola] lipolytica and [ Aestuariibacter] litoralis should be reassigned to the novel genus as Aliiglaciecola lipolytica comb. nov. (type strain, E3T = JCM 15139T = CGMCC 1.7001T) and Aliiglaciecola litoralis comb. nov. (type strain, KMM 3894T = JCM 15896T = NRIC 0754T), respectively. Aliiglaciecola lipolytica is proposed as the type species of this new genus. Physiologically, the combined characteristics of positive reactions for nitrate reduction and growth at 4 °C and 36 °C distinguish the new genus from the genera Aestuariibacter and Glaciecola by one to three traits. Moreover, the new genus is also distinguished from the genus Glaciecola by the fatty acid profile and distinguished from the genus Aestuariibacter by the differences of major isoprenoid quinone (MK-7 vs Q-8) and DNA G+C content (40.8–43.0 mol% vs 48.0–54.0 mol%).

Neiella marina gen. nov., sp. nov., isolated from the sea cucumber Apostichopus japonicus

A novel strain, designated J221(T), was isolated from the intestine of a sea cucumber, Apostichopus japonicus, collected from earthen ponds in Qingdao, China. The strain was Gram-negative, oxidase-positive, aerobic, rod-shaped and motile by means of one to several polar flagella. Growth of strain J221(T) was observed at temperatures between 10 and 40 °C with optimum growth between 25 and 28 °C. The pH range for growth was 5.0-9.0 with optimum growth at pH 7.5-8.0. The dominant fatty acids were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c, 29.04 %), C16 : 0 (28.93 %) and C18 : 1ω7c (26.15 %). The major polar lipids were phosphatidylglycerol and phosphatidylethanolamine. Diphosphatidylglycerol, an unknown aminolipid and an unknown aminophospholipid were present in moderate to minor amounts in the polar lipid profile. Strain J221(T) had Q-8 as the major respiratory quinone. The DNA G+C content of strain J221(T) was 46.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain J221(T) is a member of the Gammaproteobacteria. It formed a distinct phyletic line with less than 91 % sequence similarity to any species within previously recognized genera. On the basis of this polyphasic taxonomic study, strain J221(T) should be classified as a representative of a novel species of a new genus, for which the name Neiella marina gen. nov., sp. nov. is proposed. The type strain of Neiella marina is J221(T) ( = CGMCC 1.10130(T) = NRRL B-51319(T)).

Catenovulum agarivorans gen. nov., sp. nov., a peritrichously flagellated, chain-forming, agar-hydrolysing gammaproteobacterium from seawater

A novel Gram-negative, strictly aerobic, agar-hydrolysing bacterium, designated YM01T, was isolated from seawater samples collected from the Yellow Sea (coastal region of Qingdao, PR China). Cells were rod-shaped, peritrichously flagellated and formed long chains end-to-end. The isolate had an absolute requirement for Na+ ions, but not seawater, for growth and grew optimally at about 28 °C, in 2 % NaCl and at pH 8.0–9.0. The isolate could not be cultured in marine broth 2216, but grew well on marine agar 2216. YM01T was able to hydrolyse cellulose, starch, aesculin and Tween 80, but not egg yolk, gelatin, urea or casein. 16S rRNA gene sequence analysis demonstrated that this isolate was unique, showing only 88.4–91.0 % sequence similarity to its closest neighbours, including members of the genera Glaciecola (88.4–91.0 %), Alteromonas (88.7–89.6 %), Aestuariibacter (89.3–90.4 %), Salinimonas (89.0 %), Bowmanella (90.1–90.3 %) and Agarivorans (88.5–89.9 %). Phylogenetic analyses demonstrated that strain YM01T formed a distinct clade closely related to species of the family Alteromonadaceae within the group of Alteromonas-like gammaproteobacteria. It contained menaquinone MK-7 as the predominant isoprenoid quinone and C16 : 0 (38.3 %), C16 : 1ω7c and/or iso-C15 : 0 2-OH (29.0 %), C18 : 1ω7c (9.3 %) and C10 : 0 3-OH (8.2 %) as major cellular fatty acids. Phosphatidylethanolamine, phosphatidylglycerol and an aminophospholipid were the major phospholipid constituents. The DNA G+C content was 44.8 mol%. Based on its phenotypic, chemotaxonomic and phylogenetic distinctiveness, strain YM01T is considered to represent a novel species in a new genus in the Gammaproteobacteria, for which the name Catenovulum agarivorans gen. nov., sp. nov. is proposed; the type strain of Catenovulum agarivorans is YM01T ( = CGMCC 1.10245T  = DSM 23111T  = JCM 16580T).

Marinobacter oulmenensis sp. nov., a moderately halophilic bacterium isolated from brine of a salt concentrator

A Gram-negative, aerobic, moderately halophilic bacterium, designated Set74(T), was isolated from brine of a salt concentrator at Ain Oulmene, Algeria. The strain grew optimally at 37-40 °C, at pH 6.5-7.0 and with 5-7.5 % (w/v) NaCl and used various organic compounds as sole carbon, nitrogen and energy sources. Ubiquinone 9 (Q-9) was the major lipoquinone. The main cellular fatty acids were C₁₆:₀, C₁₈:₁ω9c, summed feature 7 (ECL 18.846; C₁₉:₀ cyclo ω10c and/or C₁₉:₁ω6c), C₁₂:₀ 3-OH, C₁₆:₁ω9c, C₁₈:₀ and C₁₂:₀. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine. The G+C content of the genomic DNA was 57.4 mol%. The 16S rRNA gene sequence analysis indicated that strain Set74(T) was a member of the genus Marinobacter. The closest relatives of strain Set74(T) were Marinobacter santoriniensis NKSG1(T) (97.5 % 16S rRNA gene sequence similarity) and Marinobacter koreensis DD-M3(T) (97.4 %). DNA-DNA relatedness between strain Set74(T) and M. santoriniensis DSM 21262(T) and M. koreensis DSM 17924(T) was 45 and 37 %, respectively. On the basis of the phenotypic, chemotaxonomic and phylogenetic features, a novel species, Marinobacter oulmenensis sp. nov., is proposed. The type strain is Set74(T) ( = CECT 7499(T)  = DSM 22359(T)).

Aliagarivorans marinus gen. nov., sp. nov. and Aliagarivorans taiwanensis sp. nov., facultatively anaerobic marine bacteria capable of agar degradation

Two agarolytic strains of Gram-negative, heterotrophic, facultatively anaerobic, marine bacteria, designated AAM1T and AAT1T, were isolated from seawater samples collected in the shallow coastal region of An-Ping Harbour, Tainan, Taiwan. Cells grown in broth cultures were straight rods that were motile by means of a single polar flagellum. The two isolates required NaCl for growth and grew optimally at about 25-30 degrees C, in 2-4% NaCl and at pH 8. They grew aerobically and could achieve anaerobic growth by fermenting D-glucose or other sugars. The major isoprenoid quinone was Q-8 (79.8-92.0%) and the major cellular fatty acids were summed feature 3 (C16:1omega7c and/or iso-C15:0 2-OH; 26.4-35.6%), C18:1omega7c (27.1-31.4%) and C16:0 (14.8-16.3%) in the two strains. Strains AAM1T and AAT1T had DNA G+C contents of 52.9 and 52.4 mol%, respectively. The two strains had a 16S rRNA gene sequence similarity of 98.6% and shared 84.9-92.4% sequence similarity with the type strains of Agarivorans albus (91.2-92.4%), eight Alteromonas species (84.9-87.1%), two Aestuariibacter species (86.0-87.0%), Bowmanella denitrificans (86.1-86.7%), eight Glaciecola species (85.0-87.9%) and Salinimonas chungwhensis (85.9-86.1%). Despite their high sequence similarity, strains AAM1T and AAT1T had a DNA-DNA relatedness value of only 4.5%. The data obtained from these polyphasic taxonomic studies revealed that the two agarolytic isolates could be classified as representatives of two novel species in a new genus, Aliagarivorans gen. nov., with Aliagarivorans marinus sp. nov. [type strain is AAM1T (=BCRC 17888T=JCM 15522T)] as the type species and Aliagarivorans taiwanensis sp. nov. [type strain is AAT1T (=BCRC 17889T=JCM 15537T)] as a second species.

Alteromonas hispanica sp. nov., a polyunsaturated-fatty-acid-producing, halophilic bacterium isolated from Fuente de Piedra, southern Spain

Strain F-32T, which produces exopolysaccharides and contains polyunsaturated fatty acids, was isolated from a hypersaline water sample collected from Fuente de Piedra (southern Spain). Phylogenetic analyses indicated conclusively that the strain in question belonged to the genus Alteromonas. Phenotypic tests showed that it could be assigned to the genus Alteromonas although it had a number of distinctive characteristics: it is moderately halophilic, growing best with 7·5–10 % w/v NaCl; it grows at 4 °C and produces H2S; it does not grow with d-cellobiose, d-fructose, d-galactose, d-glucose or lactose as sole sources of carbon and energy; and its fatty-acid profile is typical of Alteromonas but it also contains a large amount of an unusual acid with three double bonds [18 : 3ω6c (6, 9, 12); 5·01 %, w/v]. The major isoprenoid quinone is Q8. The DNA G+C content is 46·3 mol%. The phylogenetic, phenotypic and genetic properties of strain F-32T place it within a novel species, for which the name Alteromonas hispanica sp. nov. is proposed. The type strain is F-32T (=CECT 7067T=LMG 22958T).

Salinimonas chungwhensis gen. nov., sp. nov., a moderately halophilic bacterium from a solar saltern in Korea

A halophilic non-spore-forming bacterium of the γ-Proteobacteria, designated strain BH030046T, was isolated from a solar saltern in Korea. Cells were Gram-negative, chemoheterotrophic, short rod-shaped and motile with a polar flagellum. Comparative 16S rRNA gene sequence analysis revealed that strain BH030046T formed a distinct lineage in the family Alteromonadaceae and was distinguished from its closest related genera Alteromonas (91·4–94·8 %), Aestuariibacter (92·1–93·5 %) and Glaciecola (92·1–93·5 %) on the basis of low 16S rRNA gene sequence similarities. Physiological and biochemical data also showed that the isolate was different from members of these three genera. The predominant cellular fatty acids were C16 : 0 and C18 : 1 ω7c. DNA G+C content was 48 mol% and the major isoprenoid quinone was Q-8. The strain grew optimally at 30–35 °C, pH 7·0–8·0 and 2–5 % NaCl. On the basis of physiological and molecular properties, strain BH030046T (=KCTC 12239T=DSM 16280T) represents a novel genus and species in the family Alteromonadaceae, for which the name Salinimonas chungwhensis gen. nov., sp. nov. is proposed.