Psychromarinibacter sediminicola sp. nov., a novel moderately halophilic, metabolically diverse bacterium isolated from a solar saltern sediment, and comparison between members of family Roseobacteraceae

Known for its species abundance and evolutionary status complexity, family Roseobacteraceae is an important subject of many studies on the discovery, identification, taxonomic status, and ecological properties of marine bacteria. This study compared and analyzed the phylogenetic, genomic, biochemical, and chemo taxonomical properties of seven species from three genera (Psychromarinibacter, Lutimaribacter, and Maritimibacter) of the family Roseobacteraceae. Moreover, a novel strain, named C21-152T was isolated from solar saltern sediment in Weihai, China. The values of 16S rRNA gene sequence similarity, the average nucleotide identity (ANI), the average amino acid identity (AAI), and the digital DNA-DNA hybridization (dDDH) between genomes of the novel strain and Psychromarinibacter halotolerans MCCC 1K03203T were 97.19, 78.49, 73.45, and 21.90%, respectively. Genome sequencing of strain C21-152T revealed a complete Sox enzyme system related to thiosulfate oxidization as well as a complete pathway for the final conversion of hydroxyproline to α-ketoglutarate. In addition, strain C21-152T was resistant to many antibiotics and had the ability to survive below 13% salinity. This strain had versatile survival strategies in saline environments including salt-in, compatible solute production and compatible solute transport. Some of its physiological features enriched and complemented the knowledge of the characteristics of the genus Psychromarinibacter. Optimum growth of strain C21-152T occurred at 37 ℃, with 5-6% (w/v) NaCl and at pH 7.5. According to the results of the phenotypic, chemotaxonomic characterization, phylogenetic properties and genome analysis, strain C21-152T should represent a novel specie of the genus Psychromarinibacter, for which the name Psychromarinibacter sediminicola sp. nov. is proposed. The type strain is C21-152T (= MCCC 1H00808T = KCTC 92746T = SDUM1063002T).

Adaptive changes of swimming crab (Portunus trituberculatus) associated bacteria helping host against dibutyl phthalate toxification

The pollution of dibutyl phthalate (DBP) in aquatic environments is becoming an extensive environmental problem and detrimental to aquatic animals. Here, we quantified the response pattern of the bacterial community and metabolites of swimming crab (Portunus trituberculatus) juveniles exposed to 0.2, 2, and 10 mg/L DBP using 16 S rRNA gene amplicon sequencing coupled with metabolomic technique. The results showed that DBP changed the bacterial community compositions in a concentration-dependent pattern and decreased the Shannon index at the second developmental stage of the swimming crabs. The Rhodobacteraceae taxa were specifically enriched by crabs when challenged by 2 and 10 mg/L DBP, with an increased in Shannon index and enhanced drift in its assembly. Moreover, DBP changed the metabolic profiling of the swimming crab, highlighted by increased levels of lactate, valine, methionine, lysine, and phenylalanine in the 10 mg/L DBP-exposed crabs. Rhodobacteraceae presented the most considerable contribution to the metabolic potentials in phthalate and benzoate degradation, lactate production, and amino acid biosynthesis. Overall, our results indicated an adaptive change of crab-associated bacteria helped the host resist DBP stress. The findings extend our insights into the relationship between the microbiota and its host metabolism under DBP stress and reveal the potential microbiota modalities for DBP detoxification.

Alcanivorax quisquiliarum sp. nov., isolated from anaerobic fermentation liquid of food waste by high-throughput cultivation

Strain CY1518^T was isolated from an anaerobic fermentation liquid of food waste treatment plant in Beijing, PR China, and characterized to assess its taxonomy. Cells of CY1518^T were Gram-stain-negative, oxidase-negative, catalase-positive and ellipsoidal. Growth occurred at 20-42 °C (optimum, 37 °C), pH 6.0-10.0 (optimum, pH 8) and with 0-6.0 % (w/v) NaCl (optimum, 1.5%). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CY1518^T belongs to the genus Alcanivorax, with the highest sequence similarity to Alcanivorax pacificus W11-5^T (95.97 %), followed by Alcanivorax indicus SW127^T (95.08%). The similarity between strain CY1518^T and other strains of Alcanivorax was less than 95 %. The genomic DNA G+C content of strain CY1518^T was 60.88 mol%. The average nucleotide identity, average amino acid identity and digital DNA-DNA hybridization values between strain CY1518^T and the closely related taxa A. pacificus W11-5^T and A. indicus SW127^T were 77.61, 78.03 and 21.2 % and 74.15, 70.02 and 19.3%, respectively. The strain was able to use d-serine, Tween 40 and some organic acid compounds for growth. The polar lipids comprised aminophospholipid, diphosphatidylglycerol, glycolipid, an unknown polar lipid, phosphatidylethanolamine, phosphatidylglycerol and phospholipid. The principal fatty acids (>5 %) were C_19 : 0 cyclo ω8c (36.3%), C_16 : 0 (32.3%), C_12 : 0 3-OH (8.3%) and C_12 : 0 (7.6%). Based on its phenotypic, genotypic and genomic characteristics, strain CY1518^T represents a novel species in the genus Alcanivorax, for which the name Alcanivorax quisquiliarum sp. nov. is proposed. The type strain is CY1518^T (=GDMCC 1.2918^T=JCM 35120^T).

Isolation of Thalassobius mangrovi sp. nov., a novel bacterium in the family Rhodobacteraceae, from marine mangrove sediment

A Gram-stain-negative, strictly aerobic and oval-shaped bacterial strain with a flagellum, designated GS-10^T, was isolated from mangrove wetland sediment. GS-10^T grew at 20-40 °C (optimum, 37 °C), in the pH range of 5.0-11.0 (optimum, 6.0-8.0) and under various NaCl concentrations from 1 to 11 % (w/v) (optimum, 5-6 %). The respiratory quinone was ubiquinone-10, and the predominant polar lipids were phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The major fatty acids (>10 % of the total fatty acids) were summed feature 4 (C_17 : 1iso I/anteiso B) and summed feature 8 (C_18 : 1ω7c and/or C_18 : 1ω6c). The G+C content of the genomic DNA was 63.71 %. On the basis of the results from comparative analysis of the 16S rRNA gene sequence, GS-10^T represents a member of the family Rhodobacteraceae and had the highest sequence similarity to Thalassobius gelatinovorus CECT 4357^T (97.47 %), followed by Lutimaribacter pacificus W11-2B^T (97.03 %), Marivita cryptomonadis CL-SK44^T (96.83 %), Thalassobius autumnalis CECT 5118^T (96.75 %) and Thalassobius mediterraneus CECT 5383^T (96.68 %). Phylogenetic trees based on 16S rRNA gene sequences, multilocus sequence analysis (MLSA) and whole genome sequences revealed that GS-10^T clustered with species within the genus Thalassobius. The average nucleotide identity (ANI) and the average amino acid identity (AAI) values were calculated from complete genome sequences and indicated that GS-10^T represented a novel species of the genus Thalassobius, and the name Thalassobius mangrovi sp. nov. is proposed for this species. The type strain of Thalassobius mangrovi is GS-10^T (=MCCC 1K03624^T=KCTC 82131^T).

Effects of Elevated pCO2 on the Survival and Growth of Portunus trituberculatus

Identifying the response of Portunus trituberculatus to ocean acidification (OA) is critical to understanding the future development of this commercially important Chinese crab species. Recent studies have reported negative effects of OA on crustaceans. Here, we subjected swimming crabs to projected oceanic CO₂ levels (current: 380 μatm; 2100: 750 μatm; 2200: 1500 μatm) for 4 weeks and analyzed the effects on survival, growth, digestion, antioxidant capacity, immune function, tissue metabolites, and gut bacteria of the crabs and on seawater bacteria. We integrated these findings to construct a structural equation model to evaluate the contribution of these variables to the survival and growth of swimming crabs. Reduced crab growth shown under OA is significantly correlated with changes in gut, muscle, and hepatopancreas metabolites whereas enhanced crab survival is significantly associated with changes in the carbonate system, seawater and gut bacteria, and activities of antioxidative and digestive enzymes. In addition, seawater bacteria appear to play a central role in the digestion, stress response, immune response, and metabolism of swimming crabs and their gut bacteria. We predict that if anthropogenic CO₂ emissions continue to rise, future OA could lead to severe alterations in antioxidative, immune, and metabolic functions and gut bacterial community composition in the swimming crabs through direct oxidative stress and/or indirect seawater bacterial roles. These effects appear to mediate improved survival, but at the cost of growth of the swimming crabs.

Alcanivorax indicus sp. nov., isolated from seawater

A Gram-stain-negative, motile, rod-shaped bacterium, designated SW127^T, was isolated from a seawater sample collected from the Indian Ocean. Strain SW127^T was aerobic, catalase- and oxidase-positive, and grew at 8-42 °C (optimum, 30 °C), at pH 5.5-9.0 (optimum, pH 7.5) and in the presence of 0.5-11.0 % (w/v) NaCl (optimum, 3.0-4.0 %). Comparative analysis of 16S rRNA gene sequences indicated that strain SW127^T belonged to the genus Alcanivorax, and closely related to Alcanivorax pacificus MCCC 1A00474^T (96.7 % sequence similarity). The predominant cellular fatty acids of strain SW127^T were C16 : 0 and summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c). Strain SW127^T contained phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids. The genomic DNA G+C content of strain SW127^T was 62.8 mol%. On the basis of its phenotypic characteristics and phylogenetic data, strain SW127^T represents a novel species of the genus Alcanivorax, for which the name Alcanivorax indicus sp. nov. is proposed. The type strain is SW127^T (=CGMCC 1.16233^T=KCTC 62652^T).

Genome Sequence of Oceanicola sp. Strain MCTG156(1a), Isolated from a Scottish Coastal Phytoplankton Net Sample

Oceanicola sp. strain MCTG156(1a) was isolated from a phytoplankton net sample collected on the west coast of Scotland and selected based on its ability to degrade polycyclic aromatic hydrocarbons. Here, we present the genome sequence of this strain, which comprises 3,881,122 bp with 3,949 genes and an average G+C content of 62.7%.

Lacimonas salitolerans gen. nov., sp. nov., isolated from surface water of a saline lake

A Gram-stain-negative bacterium, strain TS-T30T, was isolated from a saline lake (Lake Tuosu) in Qaidam basin, Qinghai province, China, and its taxonomic position was determined by using a polyphasic approach. Cells were non-spore-forming rods, non-motile, 0.8–1.4 μm wide and 1.9–4.0 μm long. Strain TS-T30T was strictly heterotrophic and aerobic. Catalase- and oxidase-positive. Growth was observed in the presence of 0.5–11.0 % (w/v) NaCl (optimum 3.0 %), and at 10–35 °C (optimum 25 °C) and pH 6.5–10.0 (optimum pH 8.5). Strain TS-T30T contained C18 : 1ω7c as the only predominant fatty acid. The major respiratory quinone was Q-10. The DNA G+C content was 62 mol% (T m). Phylogenetic trees based on 16S rRNA gene sequences showed that strain TS-T30T formed a distinct lineage that was independent of other most closely related genera: Lutimaribacter (95.2–95.9 % 16S rRNA gene sequence similarities), Poseidonocella (95.4 %), Ruegeria (92.8–94.9 %), Marivita (93.6–94.9 %), Seohaeicola (94.7 %), Sediminimonas (94.7 %), Shimia (93.9–94.7 %), Oceanicola (92.6–94.5 %) and Roseicyclus (94.5 %). The major polar lipids were phosphatidylglycerol, one unidentified phospholipid and an unknown aminolipid; phosphatidylcholine was not detected. These data demonstrated that strain TS-T30T represents a novel species of a new genus in the family Rhodobacteraceae, for which the name Lacimonas salitolerans gen. nov., sp. nov. is proposed. The type strain of the type species is TS-T30T ( = CGMCC 1.12477T = NBRC 110969T).

Polycyclic aromatic hydrocarbons in deep sea sediments: Microbe-pollutant interactions in a remote environment

Recalcitrant polycyclic aromatic hydrocarbons (PAHs) released into seawater end up in the deep sea sediments (DSSs). However, their fate here is often oversimplified by theoretical models. Biodegradation of PAHs in DSSs, is assumed to be similar to biodegradation in surface habitats, despite high hydrostatic pressures and low temperatures that should significantly limit PAH biodegradation. Bacteria residing in the DSSs (related mainly to α- and γ-Proteobacteria) have been shown to or predicted to possess distinct genes, enzymes and metabolic pathways, indicating an adaptation of these bacterial communities to the psychro-peizophilic conditions of the DSSs. This work summarizes some of the most recent research on DSS hydrocarbonoclastic populations and mechanisms of PAH degradation and discusses the challenges posed by future high CO2 and UV climate scenarios on biodegradation of PAHs in DSSs.

Mameliella atlantica sp. nov., a marine bacterium of the Roseobacter clade isolated from deep-sea sediment of the South Atlantic Ocean

A taxonomic study was carried out on strain L6M1-5T, which was isolated from deep-sea sediment collected from the South Atlantic Ocean. The isolate was Gram-reaction-negative, oxidase-negative and catalase-weakly positive. Growth was observed in the presence of 0.5–15 % (w/v) NaCl (optimum 3–5 %), at 10–41 °C (optimum 28–30 °C), and pH 5.0–10.5 (optimum pH 7.0). The principal fatty acids were summed feature8 (C18 : 1ω7c/ω6c) (84.2 %), C18 : 0 (6.3 %), C12 : 1 3-OH (3.2 %) and C16 : 0 (2.7 %). The polar lipid profile comprised phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids, two unknown phospholipids and one unknown lipid. Ubiquinone-10 was the major quinone. The G+C content of the genomic DNA was 66.0 mol %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain L6M1-5T belonged to the genus Mameliella and shared 95.8 % sequence similarity with Mameliella alba JLT354-WT. The combined genotypic and phenotypic data show that strain L6M1-5T represents a novel species of the genus Mameliella, for which the name Mameliella. atlantica sp. nov. is proposed. The type strain is L6M1-5T ( = MCCC 1A07531T = JCM 30230T).

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)).

Oceanicola antarcticus sp. nov. and Oceanicola flagellatus sp. nov., moderately halophilic bacteria isolated from seawater

Two Gram-stain-negative, aerobic, moderately halophilic, rod-shaped bacteria (strains Ar-45T and DY470T) were isolated from seawater collected from the Southern Ocean and the Pacific Ocean, respectively. Growth of strain Ar-45T was observed with between 0.5 and 10.0 % (w/v) NaCl (optimally with 0.5–3.0 %) and between pH 5.5 and 9.5. Strain DY470T grew in the presence of 0.5–7.5 % (w/v) NaCl (optimally with 2.0 %) and at pH 5.5–8.5. Chemotaxonomic analysis showed Q-10 as the respiratory quinone for both strains. The major fatty acids (>5 %) of strain Ar-45T were C16 : 0, C19 : 0 cyclo ω8c and C18 : 1ω7c, while those of strain DY470T were C18 : 1ω7c, C16 : 0 and 11-methyl C18 : 1ω7c. The DNA G+C contents of the two strains were 62.0 and 61.8 mol%, respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that strains Ar-45T and DY470T were related most closely to the genus Oceanicola , with sequence similarities of 97.4–94.0 and 97.7–94.7 %, respectively. The DNA–DNA hybridization value between strain Ar-45T and Oceanicola marinus LMG 23705T was 22.0 %. Levels of DNA–DNA relatedness between strain DY470T and Oceanicola nitratireducens LMG 24663T and Oceanicola batsensis DSM 15984T were 32.5 and 26.1 %, respectively. Based on phylogenetic, chemotaxonomic and phenotypic data, strains Ar-45T and DY470T are considered to represent two novel species of the genus Oceanicola , for which the names Oceanicola antarcticus (type strain Ar-45T = CGMCC 1.12662T = LMG 27868T) and Oceanicola flagellatus (type strain DY470T = CGMCC 1.12664T = LMG 27871T) are proposed.

Genome sequence and emended description of Leisingera nanhaiensis strain DSM 24252(T) isolated from marine sediment

Leisingera nanhaiensis DSM 24252^T is a Gram-negative, motile, rod-shaped marine Alphaproteobacterium, isolated from sandy marine sediments. Here we present the non-contiguous genome sequence and annotation together with a summary of the organism's phenotypic features. The 4,948,550 bp long genome with its 4,832 protein-coding and 64 RNA genes consists of one chromosome and six extrachromosomal elements with lengths of 236 kb, 92 kb, 61 kb, 58 kb, 56 kb, and 35 kb, respectively. The analysis of the genome showed that DSM 24252^T possesses all genes necessary for dissimilatory nitrite reduction, and the strain was shown to be facultatively anaerobic, a deviation from the original description that calls for an emendation of the species. Also present in the genome are genes coding for a putative prophage, for gene-transfer agents and for the utilization of methylated amines. Phylogenetic analysis and intergenomic distances indicate that L. nanhaiensis might not belong to the genus Leisingera.

Genome sequence of Phaeobacter daeponensis type strain (DSM 23529(T)), a facultatively anaerobic bacterium isolated from marine sediment, and emendation of Phaeobacter daeponensis

TF-218^T is the type strain of the species Phaeobacter daeponensis Yoon et al. 2007, a facultatively anaerobic Phaeobacter species isolated from tidal flats. Here we describe the draft genome sequence and annotation of this bacterium together with previously unreported aspects of its phenotype. We analyzed the genome for genes involved in secondary metabolite production and its anaerobic lifestyle, which have also been described for its closest relative Phaeobacter caeruleus. The 4,642,596 bp long genome of strain TF-218^T contains 4,310 protein-coding genes and 78 RNA genes including four rRNA operons and consists of five replicons: one chromosome and four extrachromosomal elements with sizes of 276 kb, 174 kb, 117 kb and 90 kb. Genome analysis showed that TF-218^T possesses all of the genes for indigoidine biosynthesis, and on specific media the strain showed a blue pigmentation. We also found genes for dissimilatory nitrate reduction, gene-transfer agents, NRPS/ PKS genes and signaling systems homologous to the LuxR/I system.

Genome sequence of Phaeobacter caeruleus type strain (DSM 24564(T)), a surface-associated member of the marine Roseobacter clade

In 2009 Phaeobacter caeruleus was described as a novel species affiliated with the marine Roseobacter clade, which, in turn, belongs to the class Alphaproteobacteria. The genus Phaeobacter is well known for members that produce various secondary metabolites. Here we report of putative quorum sensing systems, based on the finding of six N-acyl-homoserine lactone synthetases, and show that the blue color of P. caeruleus is probably due to the production of the secondary metabolite indigoidine. Therefore, P. caeruleus might have inhibitory effects on other bacteria. In this study the genome of the type strain DSM 24564^T was sequenced, annotated and characterized. The 5,344,419 bp long genome with its seven plasmids contains 5,227 protein-coding genes (3,904 with a predicted function) and 108 RNA genes.

Draft genome sequence of the xylan-degrading marine bacterium strain S124, representing a novel species of the genus Oceanicola

We isolated a xylan-degrading bacterium from seawater of Micronesia and identified it as Oceanicola sp. strain S124. We sequenced the Oceanicola sp. S124 genome using GSFLX 454 pyrosequencing and predicted 4,433 open reading frames (ORFs) including putative saccharification and phage-related genes.

Oceanicola litoreus sp. nov., an alphaproteobacterium isolated from the seashore sediment

A Gram-negative, non-motile, facultatively aerobic and rod-shaped bacterial strain, designated M-M22(T), was isolated from seashore sediment on the southern coast in Korea, and its taxonomic position was investigated by using a polyphasic approach. Strain M-M22(T) was observed to grow optimally at pH 7.0-7.5, at 30 °C and in the presence of 2 % (w/v) NaCl. Neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain M-M22(T) fell within the clade comprising the type strains of Oceanicola species, except Oceanicola granulosus. Strain M-M22(T) exhibited the highest 16S rRNA gene sequence similarity values (each 95.4 %) to the type strains of Oceanicola batsensis and Oceanicola nitratireducens and 93.9-94.8 % sequence similarity to the type strains of the other Oceanicola species Strain M-M22(T) was found to contain Q-10 as the predominant ubiquinone and C18:1 ω7c as the predominant fatty acid. Major polar lipids were determined to be phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid and one unidentified lipid. The DNA G+C content was determined to be 67.6 mol%. Differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain M-M22(T) is distinguished from other Oceanicola species. On the basis of the data presented, strain M-M22(T) is considered to represent a novel species of the genus Oceanicola, for which the name Oceanicola litoreus sp. nov. is proposed. The type strain is M-M22(T) (= KCTC 32083(T) = CCUG 62794(T)).

Huaishuia halophila gen. nov., sp. nov., isolated from coastal seawater

A novel Gram-negative, non-motile bacterium, designated ZXM137T, was isolated from seawater collected from a coastal region of Qingdao, China, during a massive green algae (Enteromorpha prolifera) bloom. Strain ZXM137T was strictly aerobic and did not accumulate poly-β-hydroxybutyrate. Growth occurred with 0.5–11.0 % (w/v) NaCl, at pH 6–9 (optimum of pH 7) and at 4–45 °C (optimum at 28 °C). It contained Q-10 as the predominant ubiquinone and the major polar lipids were phosphatidylglycerol, phospholipids, and an unidentified aminolipid and lipid. The major cellular fatty acids of strain ZXM137T were C18 : 1ω7c, C18 : 1ω6c and 11-methyl C18 : 1ω7c. The DNA G+C content was 60.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain ZXM137T formed a distinct evolutionary lineage within the Roseobacter group in the class Alphaproteobacteria. On the basis of phenotypic, chemotaxonomic and phylogenetic evidence, strain ZXM137T represents a novel species in a new genus, for which the name Huaishuia halophila gen. nov., sp. nov. is proposed; the type strain is ZXM137T ( = CGMCC 1.8891T = LMG 24854T).

Nitratireductor pacificus sp. nov., isolated from a pyrene-degrading consortium

Strain pht-3BT was isolated from a pyrene-degrading consortium of an enriched sediment from the Pacific Ocean, collected during the screening of polycyclic aromatic hydrocarbon-degrading bacteria. Cells were Gram-negative, short rods that were motile by means of flagella. Growth was observed at 0–7 % NaCl and 10–41 °C. The isolate was able to reduce nitrate to nitrite, but not to nitrogen. 16S rRNA gene sequence comparisons showed that strain pht-3BT was most closely related to Nitratireductor aquibiodomus NL21T (97.3 % 16S rRNA gene sequence similarity), N. indicus C115T (97.1 %), N. basaltis J3T (96.8 %) and N. kimnyeongensis KY 101T (96.7 %). DNA–DNA hybridization between strain pht-3BT and these reference strains revealed 55, 54, 28 and 42 % DNA–DNA relatedness, respectively. The dominant fatty acids were C19 : 0ω8c cyclo (22.6 %) and summed feature 8 (consisting of C18 : 1ω7c and/or C18 : 1ω6c; 60.4 %). The G+C content of the chromosomal DNA was 63 mol%. These characteristics were in good agreement with those of members of the genus Nitratireductor. According to cell morphology, physiology, fatty acid composition, 16S rRNA gene sequence analysis and DNA–DNA relatedness, the isolate belonged to the genus Nitratireductor but could be readily distinguished from recognized species of the genus. Therefore a novel species is proposed to accommodate strain pht-3BT, for which the name Nitratireductor pacificus sp. nov. is proposed. The type strain is pht-3BT ( = CCTCC AB 209302T = LMG 25541T = MCCC 1A01024T).

Alcanivorax pacificus sp. nov., isolated from a deep-sea pyrene-degrading consortium

A taxonomic study was carried out on a novel bacterial strain, designated W11-5T, which was isolated from a pyrene-degrading consortium enriched from deep-sea sediment of the Pacific Ocean. The isolate was Gram-reaction-negative and oxidase- and catalase-positive. Growth was observed in 0.5–12 % (w/v) NaCl and at 10–42 °C. On the basis of 16S rRNA gene sequence analysis, strain W11-5T was shown to belong to the genus Alcanivorax with a close relation to A. dieselolei B-5T (93.9 % 16S rRNA sequence similarity), A. balearicus MACL04T (93.1 %), A. hongdengensis A-11-3T (93.1 %), A. borkumensis SK2T (93.0 %), A. venustensis ISO4T (93.0 %) and A. jadensis T9T (92.9 %). Similarities between the gyrB gene sequences of W11-5T and other species of the genus Alcanivorax were between 76.8 and 80.8 %. The principal fatty acids were C12 : 0 3-OH (8.0 %), C16 : 0 (29.1 %) and C18 : 1ω7c (27.4 %). The G+C content of the chromosomal DNA was 60.8 mol%. Based on its morphology, physiology and fatty acid composition as well as the results of 16S rRNA and gyrB gene sequence analyses, strain W11-5T ( = MCCC 1A00474T  = CCTCC AB 208236T  = LMG 25514T) represents a novel species of the genus Alcanivorax, for which the name Alcanivorax pacificus sp. nov. is proposed.

Oceanicola nitratireducens sp. nov., a marine alphaproteobacterium isolated from the South China Sea

A Gram-negative, non-motile, short-rod-shaped bacterial strain (JLT1210T) that accumulates poly-β-hydroxybutyrate granules was isolated from the Beibu Gulf in the South China Sea. Cells have polar or subpolar flagella. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain belongs to the genus Oceanicola in the order Rhodobacterales, class Alphaproteobacteria. The closest neighbours were Oceanicola nanhaiensis SS011B1-20T (96.5 % similarity) and Oceanicola batsensis HTCC2597T (96.4 %). The predominant respiratory ubiquinone of strain JLT1210T was Q-10 and the DNA G+C content was 72.8 mol%. Evidence from genotypic, chemotaxonomic and phenotypic data shows that strain JLT1210T represents a novel species of the genus Oceanicola, for which the name Oceanicola nitratireducens sp. nov. is proposed; the type strain is JLT1210T (=LMG 24663T=CGMCC 1.7292T).