A novel SGNH family hydrolase Ali5 with thioesterase activity and a GNSL motif but without a classic GDSL motif from Altererythrobacter ishigakiensis.

OBJECTIVE: We aimed to characterize a novel SGNH (Ser-Gly-Asn-His) family hydrolase from the annotated genome of marine bacteria with new features. RESULTS: A novel esterase Ali5 from Altererythrobacter ishigakiensis has been identified and classified into SGNH family. Ali5 presented a novel GNSL (Gly-Asn-Ser-Leu(X)) motif that differs from the classic GDSL (Gly-Asp-Ser-Leu(X)) motif of SGNH family. The enzyme has esterase and thioesterase activity and exhibited apparent temperature and pH optima of 40 °C and pH 7.5 (in phosphate buffer), respectively. Ali5 was found to be halotolerant and thermostable, and exhibited strong resistance to several organic solvents and metal ions. The residue Tyr196 has a great influence on the catalytic activity, which was proved by site-directed mutagenesis and subsequent kinetic characterization. CONCLUSION: The esterase Ali5 with esterase and thioesterase activities, salt and metal ions resistance and unique structural features was identified, which holds promise for research on the SGNH family of hydrolases.

Gracilimonas amylolytica sp. nov., isolated from deep-sea sediment.

A Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium, designated LA399T, was isolated from deep-sea sediment collected from the Pacific Ocean. Cells of strain LA399T grew in the medium containing 0-10.0 % of NaCl (w/v; optimum 3.0-5.0 %), pH 6.5-8.0 (optimum 7.0) and 20-40 °C (optimum 37 °C). Aesculin, gelatin, starch and Tween 80 were hydrolysed. Strain LA399T was closely related to Gracilimonas halophila WDS2C40T (97.0 % sequence similarity), Gracilimonas mengyeensis YIM J14T (96.4 %), Gracilimonas rosea CL-KR2T (96.4 %) and Gracilimonas tropica DSM 19535T (96.0 %), and exhibited equal or less than 96.0 % sequence similarity to other type strains of species with validly published names. Phylogenetic analyses revealed that strain LA399T clustered with the clade comprising the Gracilimonas species and formed an independent lineage. Strain LA399T contained menaquinone 7 as the sole isoprenoid quinone and iso-C15 : 0, anteiso-C15 : 0, summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and summed feature 9 (iso-C17 : 1ω9c/10-methyl C16 : 0) as the predominant cellular fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and three unidentified glycolipids. The DNA G+C content was 45.3 mol%. According to the phylogenetic, chemotaxonomic and phenotypic data, it represents a novel species of the genus Gracilimonas, for which the name Gracilimonas amylolytica is proposed. The type strain is LA399T (=CGMCC 1.16248T=KCTC 52885T).

Two novel deep-sea sediment metagenome-derived esterases: residue 199 is the determinant of substrate specificity and preference.

BACKGROUND: The deep-sea environment harbors a vast pool of novel enzymes. Owing to the limitations of cultivation, cultivation-independent has become an effective method for mining novel enzymes from the environment. Based on a deep-sea sediment metagenomics library, lipolytic-positive clones were obtained by activity-based screening methods. RESULTS: Two novel esterases, DMWf18-543 and DMWf18-558, were obtained from a deep-sea metagenomic library through activity-based screening and high-throughput sequencing methods. These esterases shared 80.7% amino acid identity with each other and were determined to be new members of bacterial lipolytic enzyme family IV. The two enzymes showed the highest activities toward p-nitrophenyl (p-NP) butyrate at pH 7.0 and 35-40 °C and were found to be resistant to some metal ions (Ba2+, Mg2+, and Sr2+) and detergents (Triton X-100, Tween 20, and Tween 80). DMWf18-543 and DMWf18-558 exhibited distinct substrate specificities and preferences. DMWf18-543 showed a catalytic range for substrates of C2-C8, whereas DMWf18-558 presented a wider range of C2-C14. Additionally, DMWf18-543 preferred p-NP butyrate, whereas DMWf18-558 preferred both p-NP butyrate and p-NP hexanoate. To investigate the mechanism underlying the phenotypic differences between the esterases, their three-dimensional structures were compared by using homology modeling. The results suggested that residue Leu199 of DMWf18-543 shortens and blocks the substrate-binding pocket. This hypothesis was confirmed by the finding that the DMWf18-558-A199L mutant showed a similar substrate specificity profile to that of DMWf18-543. CONCLUSIONS: This study characterized two novel homologous esterases obtained from a deep-sea sediment metagenomic library. The structural modeling and mutagenesis analysis provided insight into the determinants of their substrate specificity and preference. The characterization and mechanistic analyses of these two novel enzymes should provide a basis for further exploration of their potential biotechnological applications.

Characterization of a novel alkaline esterase from Altererythrobacter epoxidivorans CGMCC 1.7731T.

A novel esterase gene (e25) was identified from Altererythrobacter epoxidivorans CGMCC 1.7731T by genome sequence screening. The e25 gene is 948 nucleotides in length and encodes a 315 amino acid protein (E25) with a predicted molecular mass of 33,683 Da. A phylogenetic tree revealed that E25 belongs to the hormone-sensitive lipase (HSL) family of lipolytic enzymes. An activity assay of E25 showed that it exhibited the highest catalytic efficiency when using p-nitrophenyl caproate (C6) as a substrate. The optimum pH and temperature were determined to be approximately pH 9 and 45°C, and the Km and Vmax values were 0.12 mM and 1,772 µmol/min/mg, respectively. After an incubation at 40°C for 80 min, E25 retained 75% of its basal activity. The enzyme exhibited good tolerance to metal cations, such as Ba2+, Ca2+, and Cu2+ (10 mM), but its activity was strongly inhibited by Co2+, Ni2+, Mn2+, and Zn2+. The E25 enzyme was stimulated by glycerol and retained over 60% of its basal activity in the presence of 1% Tween-80 and Triton X-100. Overall, the activity of E25 under alkaline conditions and its organic solvent and detergent tolerance indicate that E25 could be useful as a novel industrial catalyst in biotechnological applications.

Henriciella pelagia sp. nov., isolated from seawater.

Strain LA220T, isolated from seawater of the Eastern Pacific Ocean, was subjected to a polyphasic taxonomic study. Cells of the strain were Gram-stain-negative, aerobic, motile and short rod-shaped. On the basis of 16S rRNA gene sequence analysis, strain LA220T showed high similarity to Henriciella litoralis SD10T (98.5 %), Henriciella marina DSM 19595T (98.3 %) and Henriciellaaquimarina P38T (97.5 %), and exhibited less than 97.0 % 16S rRNA gene sequence similarity with respect to the type strains of other Hyphomonadaceae species. Phylogenetic analyses revealed that strain LA220T fell within the cluster of the genus Henriciella. The average nucleotide identity and in silico DNA-DNA hybridization values between strain LA220T and the type strains of Henriciella species were 74.8-76.8 and 18.4-20.8 %, respectively. The sole respiratory quinone was ubiquinone-10 (Q-10). The principal fatty acids were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0. The major polar lipids were three unidentified glycolipids. The DNA G+C content was 59.9 mol%. Phylogenetic distinctiveness, chemotaxonomic differences and phenotypic properties revealed that strain LA220T could be differentiated from recognized Henriciella species. Therefore, strain LA220T is considered to represent a novel species of the genus Henriciella, for which the name Henriciella pelagia sp. nov. (type strain LA220T=CGMCC 1.15928T=KCTC 52577T) is proposed.

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.

Croceicoccus pelagius sp. nov. and Croceicoccus mobilis sp. nov., isolated from marine environments.

Strain Ery9T, isolated from surface seawater of the Atlantic Ocean, and strain Ery22T, isolated from deep-sea sediment of the Indian Ocean, were subjected to a taxonomic study using a polyphasic approach. Cells of the two strains were Gram-stain-negative, aerobic and rod-shaped. They produced yellow pigments and lacked bacteriochlorophyll a. On the basis of 16S rRNA gene sequence analysis, strain Ery9T was closely related to Croceicoccus naphthovorans PQ-2T (with 16S rRNA gene sequence similarity of 97.7 %), and strain Ery22T was closely related to Croceicoccusmarinus E4A9T (98.3 %). The 16S rRNA gene sequence similarity between strain Ery9T and strain Ery22T was 96.6 %. Phylogenetic analyses revealed that strains Ery9T and Ery22T fell within the cluster of the genus Croceicoccus and represented two independent lineages. The average nucleotide identity (ANI) values and the genome-to-genome distances between strains Ery9T and Ery22T and the type strains of species of the genus Croceicoccus with validly published names were 73.7-78.4 % and 20.1-22.3 %, respectively. The major respiratory quinone of the two isolates was ubiquinone-10 (Q-10). The DNA G+C contents of strains Ery9T and Ery22T were 62.8 and 62.5 mol%, respectively. Differential phylogenetic distinctiveness and chemotaxonomic differences, together with phenotypic properties, revealed that strains Ery9T and Ery22T could be differentiated from their closely related species. Therefore, it is concluded that strains Ery9T and Ery22T represent two novel species of the genus Croceicoccus, for which the names Croceicoccus pelagius sp. nov. (type strain Ery9T=CGMCC 1.15358T=DSM 101479T) and Croceicoccus mobilis sp. nov. (type strain Ery22T=CGMCC 1.15360T=DSM 101481T), are proposed.

Novosphingobium marinum sp. nov., isolated from seawater.

A Gram-stain-negative, aerobic, short rod-shaped bacterium, strain LA53(T), was isolated from a deep-sea water sample collected from the eastern Pacific Ocean. Strain LA53(T) grew in the presence of 0-7.0 % (w/v) NaCl and at 15-37 °C; optimum growth was observed with 1.0-2.0 % (w/v) NaCl and at 35 °C. Chemotaxonomic analysis showed ubiquinone-10 as the predominant respiratory quinone, C18 : 1ω7c and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c) as major fatty acids, and diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and sphingoglycolipid as major polar lipids. The genomic DNA G+C content was 57.7 mol%. Phylogenetic analyses revealed that strain LA53(T) belongs to the genus Novosphingobium. 16S rRNA gene sequence similarities between strain LA53(T) and the type strains of species of the genus Novosphingobium with validly published names ranged from 93.1 to 96.3 %. In addition, strain LA53(T) could be differentiated from Novosphingobium pentaromativorans DSM 17173(T) and Novosphingobium indicum DSM 23608(T) as well as the type strain of the type species of the genus, Novosphingobium capsulatum DSM 30196(T), by some phenotypic characteristics, including hydrolysis of substrates, utilization of carbon sources and susceptibility to antibiotics. On the basis of phenotypic and genotypic data, strain LA53(T) represents a novel species within the genus Novosphingobium, for which the name Novosphingobium marinum sp. nov. is proposed. The type strain is LA53(T) ( = CGMCC 1.12918(T) = JCM 30307(T)).

Gilvimarinus polysaccharolyticus sp. nov., an agar-digesting bacterium isolated from seaweed, and emended description of the genus Gilvimarinus.

A taxonomic study was carried out on strain YN3(T), which was isolated from a seaweed sample taken from the coast of Weihai, China. The bacterium was Gram-stain-negative, rod-shaped, and could grow at pH 5.0-10.0 and 4-32 °C in the presence of 0-9.0 % (w/v) NaCl. Strain YN3(T) was positive for the hydrolysis of polysaccharides, such as agar, starch and xylan. The predominant respiratory quinone was ubiquinone-8. The major fatty acids were C16 : 1ω7c and/or iso-C15 : 0 2-OH, C16 : 0 and C18 : 1ω7c. The main polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine, and two unidentified glycolipids. The genomic DNA G+C content was 49.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YN3(T) should be assigned to the genus Gilvimarinus. 'Gilvimarinus agarilyticus' KCTC 23325 and Gilvimarinus chinensis QM42(T) had the closest phylogenetic relationship to strain YN3(T), and showed 97.9 % and 95.8 % sequence similarities, respectively. On the basis of phenotypic, chemotaxonomic and genotypic data and DNA-DNA hybridization studies, we propose that strain YN3(T) represents a novel species of the genus Gilvimarinus, for which the name Gilvimarinus polysaccharolyticus sp. nov. is proposed. The type strain is YN3(T) ( = KCTC 32438(T) = JCM 19198(T)). An emended description of the genus Gilvimarinus is also presented.

Chryseobacterium profundimaris sp. nov., a new member of the family Flavobacteriaceae isolated from deep-sea sediment.

A Gram-stain negative, strictly aerobic, rod-shaped, non-motile bacterium, designated strain DY46(T), was isolated from Atlantic Ocean sediment. The isolate was found to grow in medium containing 0-3.0 % (w/v) NaCl (optimally at 0-1.0 %), at 4-37 °C and pH 5.0-8.0. Chemotaxonomic analysis detected MK-6 as the sole isoprenoid quinone. The major fatty acids were identified iso-C15:0, iso-C17:0 3-OH, iso-C17:1 ω9c and summed feature 3 (comprising iso-C15:0 2-OH and/or C16:1 ω7c). The DNA G + C content was determined to be 40.7 mol %. Phylogenetic analyses based on the 16S rRNA gene sequence indicated that strain DY46(T) falls within the cluster comprising Chryseobacterium species. The levels of 16S rRNA gene sequence similarity between strain DY46(T) and the type strains of the Chryseobacterium species with validly published names ranged from 92.4 to 99.1 %, the high values (>97 %) being with Chryseobacterium takakiae A1-2(T) (99.1 %), C. taiwanense BCRC 17412(T) (98.0 %), C. taeanense PHA3-4(T) (97.3 %), C. hispalense DSM 25574(T) (97.3 %), C. camelliae THG C4-1(T) (97.2 %), C. gregarium DSM 19109(T) (97.1 %) and C. wanjuense R2A10-2(T) (97.0 %). The DNA-DNA relatedness values between strain DY46(T) and the type strains of the above closely related species were 47, 57, 24, 34, 6, 40 and 21 %, respectively. On the basis of phenotypic and genotypic characteristics, strain DY46(T) represents a novel member within the genus Chryseobacterium, for which the name Chryseobacterium profundimaris is proposed. The type strain is DY46(T) (=CGMCC 1.12663(T) = JCM 19801(T)).

Paracoccus sediminis sp. nov., isolated from Pacific Ocean marine sediment.

Strain CMB17(T) was a short rod-shaped bacterium isolated from marine sediment of the Pacific Ocean. Cells were Gram-stain-negative and non-motile. Optimal growth occurred at 25-30 °C, pH 6.5-7 and 0.5-1% (w/v) NaCl. The major fatty acid was C(18 : 1)ω7c (87.59%), and ubiquinone-10 was detected as the only isoprenoid quinone. The DNA G+C content of the genomic DNA was 62.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CMB17(T) is most closely related to Paracoccus stylophorae KTW-16(T) (96.7%), P. solventivorans DSM 6637(T) (96.4%) and P. saliphilus YIM 90738(T) (96.4%). Based on phenotypic, genotypic and phylogenetic characteristics, strain CMB17(T) is proposed to represent a novel species, denominated Paracoccus sediminis sp. nov. (type strain CMB17(T) = JCM 18467(T) = DSM 26170(T) = CGMCC 1.12681(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-45(T) and DY470(T)) were isolated from seawater collected from the Southern Ocean and the Pacific Ocean, respectively. Growth of strain Ar-45(T) 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 DY470(T) 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-45(T) were C16 : 0, C19 : 0 cyclo ω8c and C18 : 1ω7c, while those of strain DY470(T) 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-45(T) and DY470(T) 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-45(T) and Oceanicola marinus LMG 23705(T) was 22.0 %. Levels of DNA-DNA relatedness between strain DY470(T) and Oceanicola nitratireducens LMG 24663(T) and Oceanicola batsensis DSM 15984(T) were 32.5 and 26.1 %, respectively. Based on phylogenetic, chemotaxonomic and phenotypic data, strains Ar-45(T) and DY470(T) are considered to represent two novel species of the genus Oceanicola, for which the names Oceanicola antarcticus (type strain Ar-45(T) = CGMCC 1.12662(T) = LMG 27868(T)) and Oceanicola flagellatus (type strain DY470(T) = CGMCC 1.12664(T) = LMG 27871(T)) are proposed.

Thalassomonas eurytherma sp. nov., a marine proteobacterium.

Two Gram-staining-negative, aerobic, rod-shaped bacterial strains, designated Za6a-12(T) and Za6a-17, were isolated from seawater of the East China Sea. Cells of Za6a-12(T) and Za6a-17 were approximately 1.5-2.0 µm×0.5-0.7 µm and motile by a single polar flagellum. Strains grew optimally at pH 7.5-8.0, 28 °C, and in the presence of 2.5-3.0% (w/v) NaCl. Chemotaxonomic analysis showed that the predominant respiratory quinone of strains Za6a-12(T) and Za6a-17 was ubiquinone-8 (>97%), and the major fatty acids were C(14 : 0), C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH, C(16 : 0) and C(17 : 1)ω8c. Their DNA G+C contents were 42.7 mol% and 42.8 mol%, respectively. 16S rRNA gene sequence analysis revealed that the isolates belonged to the genus Thalassomonas and showed the highest sequence similarity to Thalassomonas loyana CBMAI 722(T) (95.9%). Strains Za6a-12(T) and Za6a-17 could be differentiated from T. loyana CBMAI 722(T) according to their phenotypic and chemotaxonomic features, DNA G+C contents and fatty acid composition. On the basis of these features, we propose strains Za6a-12(T) and Za6a-17 to be representatives of a novel species of the genus Thalassomonas with the name Thalassomonas eurytherma sp. nov. suggested. Strain Za6a-12(T) ( = CGMCC 1.12115(T) = JCM 18482(T)) is the type strain of this novel species.

Devosia pacifica sp. nov., isolated from deep-sea sediment.

A novel bacterial strain, NH131(T), was isolated from deep-sea sediment of South China Sea. Cells were strictly aerobic, Gram-stain negative, short rod-shaped and motile with a single lateral flagellum. Strain NH131(T) grew optimally at pH 6.5-7.0 and 25-30 °C. 16S rRNA gene sequence analysis revealed that strain NH131(T) belonged to the genus Devosia, sharing the highest sequence similarity with the type strain, Devosia geojensis BD-c194(T) (96.2%). The predominant fatty acids were C(18 : 1)ω7c, 11-methyl C(18 : 1)ω7c, C(18 : 0) and C(16 : 0). Ubiquinone 10 was the predominant ubiquinone. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phospholipid, three glycolipids and two unknown lipids. The DNA G+C content of strain NH131(T) was 63.0 mol%. On the basis of the results of polyphasic identification, it is suggested that strain NH131(T) represents a novel species of the genus Devosia for which the name Devosia pacifica sp. nov. is proposed. The type strain is NH131(T) ( = JCM 19305(T) = KCTC 32437(T)).

Halopelagius longus sp. nov., a member of the family Halobacteriaceae isolated from a salt mine, and emended description of the genus Halopelagius.

A thermotolerant, extremely halophilic archaeon, BC12-B1(T), was isolated from a salt mine in Baicheng county, Xinjiang province, China. Colonies were off-white-grey. The cells stained Gram-negative, were motile and irregularly long-rod-shaped (variation in both width and length) with abundant gas vesicles. The strain was able to grow at 20-55 °C (optimum, 48 °C), at pH 6.0-8.0 (optimum, 7.0-7.3), with 1.8-6.0 M NaCl (optimum, 3.0-3.5 M) and with 0.02-2.2 M Mg(2+) (optimum, 0.1-0.2 M). Cells lysed in distilled water and the minimal NaCl concentration to prevent cell lysis was 8 % (w/v). Phylogenetic analysis based on the 16S rRNA gene sequences showed that strain BC12-B1(T) was most closely related to Halopelagius inordinatus RO5-2(T) (98.5 %) with less than 95 % sequence similarity to other described species. The genomic DNA G+C content of strain BC12-B1(T) was 64.0 mol%. The DNA-DNA hybridization value between strain BC12-B1(T) and Hpl. inordinatus RO5-2(T) was 43.6 %. The major polar lipids of strain BC12-B1(T) were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, four glycolipids and an unknown lipid. Based on phenotypic, chemotaxonomic and genotypic characteristics, strain BC12-B1(T) represents a novel species of the genus Halopelagius, for which the name Halopelagius longus sp. nov. is proposed. The type strain is BC12-B1(T) ( = CGMCC 1.12397(T) = JCM 18758(T)). An emended description of the genus Halopelagius is also provided.

Halolamina salifodinae sp. nov. and Halolamina salina sp. nov., two extremely halophilic archaea isolated from a salt mine.

Two strictly aerobic, extremely halophilic archaea, strains WSY15-H1(T) and WSY15-H3(T), were isolated from a salt mine in Wensu county, Xinjiang province, China. Cells of the two strains were Gram-stain-negative, non-motile and pleomorphic. Colonies were pink- and red-pigmented, respectively. Strain WSY15-H1(T) grew at 20-45 °C (optimum 37-42 °C), 1.6-5.4 M NaCl (optimum 3.4-3.9 M), 0-2.0 M MgCl2 (optimum 0.1-0.5 M) and pH 6.0-9.0 (optimum 7.0), whereas strain WSY15-H3(T) grew at 20-50 °C (optimum 37 °C), 1.9-5.4 M NaCl (optimum 3.4 M), 0.02-2.5 M MgCl2 (optimum 0.5-1.0 M) and pH 6.0-7.5 (optimum 6.5). The minimal NaCl concentrations to prevent cell lysis were 9 % (w/v) for strain WSY15-H1(T) and 8 % (w/v) for strain WSY15-H3(T). The major polar lipids of the two isolates were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and phosphatidylglycerol sulfate, as well as nine glycolipids for strain WSY15-H1(T) and seven glycolipids for strain WSY15-H3(T); two of these glycolipids (GL1 and GL3) were chromatographically identical to bis-sulfated diglycosyl diether (S2-DGD-1) and sulfated diglycosyl diether (S-DGD-1), respectively. The genomic DNA G+C contents of strains WSY15-H1(T) and WSY15-H3(T) were 65.4 and 66.2 mol%. On the basis of 16S rRNA gene sequence analysis, strains WSY15-H1(T) and WSY15-H3(T) shared 97.0% similarity with each other and showed respectively 98.4 and 97.6% sequence similarity to Halolamina pelagica TBN21(T), which was the only type strain that had higher than 91% sequence similarity with the two isolates. Analysis of phylogenetic relationships and DNA-DNA relatedness indicated that strains WSY15-H1(T) and WSY15-H3(T) represent two novel lineages with closest affinity to H. pelagica TBN21(T). Based on phenotypic, chemotaxonomic and genotypic characteristics, two novel species of the genus Halolamina are proposed, Halolamina salifodinae sp. nov. (type strain WSY15-H1(T) = JCM 18548(T) = GCMCC 1.12371(T)) and Halolamina salina sp. nov. (type strain WSY15-H3(T) = JCM 18549(T) = GCMCC 1.12285(T)).

Fabibacter pacificus sp. nov., a moderately halophilic bacterium isolated from seawater.

A Gram-stain-negative, aerobic, moderately halophilic bacterium, strain DY53(T), was isolated from a deep-seawater sample collected from the eastern Pacific Ocean. This isolate grew in the presence of 0.5-10.0 % (w/v) NaCl, at pH 6.5-8.5 and at 15-40 °C. The optimum NaCl concentration for growth of DY53(T) was 2 % (w/v) at 35 °C. Chemotaxonomic analysis showed MK-7 as the predominant menaquinone and iso-C15 : 0, summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c), iso-C15 : 1 G, iso-C15 : 0 3-OH and iso-C17 : 0 3-OH as major cellular fatty acids. The genomic DNA G+C content was 40.8 mol%. Phylogenetic trees based on 16S rRNA gene sequences revealed that Fabibacter halotolerans UST030701-097(T) was the closest neighbour, with 96.7 % sequence similarity. Based on phylogenetic, chemotaxonomic and phenotypic data, we propose that strain DY53(T) represents a novel species of the genus Fabibacter, for which the name Fabibacter pacificus sp. nov. is proposed. The type strain is DY53(T)( = CGMCC 1.12402(T) = JCM 18885(T)).

Halomonas zincidurans sp. nov., a heavy-metal-tolerant bacterium isolated from the deep-sea environment.

A Gram-stain-negative, aerobic, rod-like, motile by peritrichous flagella and moderately halophilic bacterium, designated strain B6(T), was isolated a deep-sea sediment collected from the South Atlantic Ocean. The isolate grew with 0.5-15 % (w/v) NaCl, at 4-37 °C and pH 5.0-8.5 and showed a high tolerance to zinc, manganese, cobalt and copper ions. The major fatty acids were C16 : 0, C19 : 0 cyclo ω8c, C12 : 0 3-OH and C12 : 0. The predominant ubiquinone was Q-9. The genomic DNA G+C content was 61.1 mol%. Phylogenetic analysis based on 16S rRNA gene comparisons indicated that strain B6(T) belonged to the genus Halomonas, and the closest relative was Halomonas xinjiangensis TRM 0175(T) (96.1 %). Based upon the phenotypic, chemotaxonomic and genetic data, strain B6(T) represents a novel species from the genus Halomonas, for which the name Halomonas zincidurans sp. nov. is proposed. The type strain is B6(T) ( = CGMCC 1.12450(T) = JCM 18472(T)).

Salinicola peritrichatus sp. nov., isolated from deep-sea sediment.

A Gram stain-negative, aerobic and rod-shaped bacterium, strain DY22(T), was isolated from a deep-sea sediment collected from the east Pacific Ocean. The isolate was found to grow in the presence of 0-20.0 % (w/v) NaCl and at pH 4.5-8.5; optimum growth was observed with 0.5-2.0 % (w/v) NaCl and at pH 5.0-7.0. Chemotaxonomic analysis showed the presence of ubiquinone-9 as predominant respiratory quinone and C16:0, C19:0 ω8c cyclo and C12:0 3-OH as major cellular fatty acids. The genomic DNA G+C content was determined to be 59.6 mol%. Comparative 16S rRNA gene sequence analysis revealed that the novel isolate belongs to the genus Salinicola. Strain DY22(T) exhibited the closest phylogenetic affinity to the type strain of Salinicola salarius with 97.2 % sequence similarity and less than 97 % sequence similarity with respect to other Salinicola species with validly published names. The DNA-DNA reassociation values between strain DY22(T) and S. salarius DSM 18044(T) was 52 ± 4 %. On the basis of phenotypic, chemotaxonomic and genotypic data, strain DY22(T) represents a novel species of the genus Salinicola, for which the name Salinicola peritrichatus sp. nov. (type strain DY22(T) = CGMCC 1.12381(T) = JCM 18795(T)) is proposed.

Complete genome sequence of Pelagibacterium halotolerans B2(T).

Pelagibacterium halotolerans B2(T) is a marine halotolerant bacterium that was isolated from a seawater sample collected from the East China Sea. Here, we present the complete genome sequence of the type strain P. halotolerans B2(T), which consists of one chromosome (3,944,837 bp; 61.4% G+C content) and one plasmid (4,050 bp; 56.1% G+C content). This is the first complete genome of a member of the Pelagibacterium genus.