Mechanism and Structural Insights Into a Novel Esterase, E53, Isolated From Erythrobacter longus.

Esterases are a class of enzymes that split esters into an acid and an alcohol in a chemical reaction with water, having high potential in pharmaceutical, food and biofuel industrial applications. To advance the understanding of esterases, we have identified and characterized E53, an alkalophilic esterase from a marine bacterium Erythrobacter longus. The crystal structures of wild type E53 and three variants were solved successfully using the X-ray diffraction method. Phylogenetic analysis classified E53 as a member of the family IV esterase. The enzyme showed highest activity against p-nitrophenyl butyrate substrate at pH 8.5-9.5 and 40°C. Based on the structural feature, the catalytic pocket was defined as R1 (catalytic center), R2 (pocket entrance), and R3 (end area of pocket) regions. Nine variants were generated spanning R1-R3 and thorough functional studies were performed. Detailed structural analysis and the results obtained from the mutagenesis study revealed that mutations in the R1 region could regulate the catalytic reaction in both positive and negative directions; expanding the bottleneck in R2 region has improved the enzymatic activity; and R3 region was associated with the determination of the pH pattern of E53. N166A in R3 region showed reduced activity only under alkaline conditions, and structural analysis indicated the role of N166 in stabilizing the loop by forming a hydrogen bond with L193 and G233. In summary, the systematic studies on E53 performed in this work provide structural and functional insights into alkaliphilic esterases and further our knowledge of these enzymes.

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.

Structural and Functional Insights Into CmGH1, a Novel GH39 Family ß-Glucosidase From Deep-Sea Bacterium.

Glucosidases play key roles in many diseases and are limiting enzymes during cellulose degradation, which is an important part of global carbon cycle. Here, we identified a novel ß-glucosidase, CmGH1, isolated from marine bacterium Croceicoccus marinus E4A9T. In spite of its high sequence and structural similarity with ß-xylosidase family members, CmGH1 had enzymatic activity toward p-nitrophenyl-ß-D-glucopyranoside (p-NPG) and cellobiose. The K m and K cat values of CmGH1 toward p-NPG were 0.332 ± 0.038 mM and 2.15 ± 0.081 min-1, respectively. CmGH1 was tolerant to high concentration salts, detergents, as well as many kinds of organic solvents. The crystal structure of CmGH1 was resolved with a 1.8 Å resolution, which showed that CmGH1 was composed of a canonical (α/ß)8-barrel catalytic domain and an auxiliary ß-sandwich domain. Although no canonical catalytic triad residues were found in CmGH1, structural comparison and mutagenesis analysis suggested that residues Gln157 and Tyr264 of CmGH1 were the active sites. Mutant Q157E significantly increased its hydrolase activity up to 15-fold, whereas Y264E totally abolished its enzymatic activity. These results might provide new insights into understanding the different catalytic mechanism during evolution for ß-glucosidases and ß-xylosidases.

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.

Biochemical and genetic characterization of a novel metallo-ß-lactamase from marine bacterium Erythrobacter litoralis HTCC 2594.

Metallo-ß-lactamases (MBLs) are a group of enzymes that can inactivate most commonly used ß-lactam-based antibiotics. Among MBLs, New Delhi metallo-ß-lactamase-1 (NDM-1) constitutes an urgent threat to public health as evidenced by its success in rapidly disseminating worldwide since its first discovery. Here we report the biochemical and genetic characteristics of a novel MBL, ElBla2, from the marine bacterium Erythrobacter litoralis HTCC 2594. This enzyme has a higher amino acid sequence similarity to NDM-1 (56%) than any previously reported MBL. Enzymatic assays and secondary structure alignment also confirmed the high similarity between these two enzymes. Whole genome comparison of four Erythrobacter species showed that genes located upstream and downstream of elbla2 were highly conserved, which may indicate that elbla2 was lost during evolution. Furthermore, we predicted two prophages, 13 genomic islands and 25 open reading frames related to insertion sequences in the genome of E. litoralis HTCC 2594. However, unlike NDM-1, the chromosome encoded ElBla2 did not locate in or near these mobile genetic elements, indicating that it cannot transfer between strains. Finally, following our phylogenetic analysis, we suggest a reclassification of E. litoralis HTCC 2594 as a novel species: Erythrobacter sp. HTCC 2594.

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.

A Novel Halotolerant Thermoalkaliphilic Esterase from Marine Bacterium Erythrobacter seohaensis SW-135.

A novel esterase gene, e69, was cloned from Erythrobacter seohaensis SW-135, which was isolated from a tidal flat sediment of the Yellow Sea in Korea. This gene is 825 bp in length and codes for a 29.54 kDa protein containing 274 amino acids. Phylogenetic analysis showed that E69 is a new member of the bacterial lipolytic enzyme family IV. This enzyme exhibited the highest level of activity toward p-nitrophenyl (NP) butyrate but little or no activity toward the other p-NP esters tested. The optimum temperature and pH of the catalytic activity of E69 were 60°C and pH 10.5, respectively. The enzyme exhibited stable activity over a wide range of alkaline pH values (7.5-9.5). In addition, E69 was found to be a halotolerant esterase as it exhibited the highest hydrolytic activity in the presence of 0.5 M NaCl and was still active in the presence of 3 M NaCl. Moreover, it possessed some degree of tolerance to Triton X-100 and several organic solvents. Through homology modeling and comparison with other esterases, it was suggested that the absence of the cap domain and its narrow substrate-binding pocket might be responsible for its narrow substrate specificity. Sequence and structural analysis results suggested that its high ratio of negatively to positively charged residues, large hydrophobic surface area, and negative electrostatic potential on the surface may be responsible for its alkaline adaptation. The results of this study provide insight into marine alkaliphilic esterases, and the unique properties of E69 make it a promising candidate as a biocatalyst for industrial 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.

Crystal structure of Pelagibacterium halotolerans PE8: New insight into its substrate-binding pattern.

Lysophospholipase_carboxylesterase (LPCE) has highly conserved homologs in many diverse species ranging from bacteria to humans, as well as substantial biological significance and potential therapeutic implications. However, its biological function and catalytic mechanism remain minimally investigated because of the lack of structural information. Here, we report the crystal structure of a bacterial esterase PE8 belonging to the LPCE family. The crystal structure of PE8 was solved with a high resolution of 1.66 Å. Compared with other homologs in the family, significant differences were observed in the amino acid sequence, three-dimensional structure, and substrate-binding pattern. Residue Arg79 undergoes configuration switching when binding to the substrate and forms a unique wall, leading to a relatively closed cavity in the substrate-binding pocket compared with the relatively more open and longer clefts in other homologs. Moreover, the mutant Met122Ala showed much stronger substrate affinity and higher catalytic efficiency because less steric repulsion acted on the substrates. Taken together, these results showed that, in PE8, Arg79 and Met122 play important roles in substrate binding and the binding pocket shaping, respectively. Our study provides new insight into the catalytic mechanism of LPCE, which may facilitate the development of structure-based therapeutics and other biocatalytic applications.

High quality draft genome sequence of an extremely halophilic archaeon Natrinema altunense strain AJ2T.

Natrinema altunense strain AJ2T, a halophilic archaeal strain, was isolated from a high-altitude (3884 m) salt lake in Xinjiang, China. This strain requires at least 1.7 M NaCl to grow and can grow anaerobically in the presence of nitrate. To understand the genetics underlying its extreme phenotype, we de novo assembled the entire genome sequence of AJ2T (=CGMCC 1.3731T=JCM 12890T). We assembled 3,774,135 bp of a total of 4.4 Mb genome in only 20 contigs and noted its high GC content (64.6%). Subsequently we predicted the gene content and generated genome annotation to identify the relationship between the epigenetic characteristics and genomic features. The genome sequence contains 52 tRNA genes, 3 rRNA genes and 4,462 protein-coding genes, 3792 assigned as functional or hypothetical proteins in nr database. This Whole Genome Shotgun project was deposited in DDBJ/EMBL/GenBank under the accession JNCS00000000. We performed a Bayesian (Maximum-Likelihood) phylogenetic analysis using 16S rRNA sequence and obtained its relationship to other strains in the Natrinema and Haloterrigena genera. We also confirmed the ANI value between every two species of Natrinema and Haloterrigena genera. In conclusion, our analysis furthered our understanding of the extreme-environment adapted strain AJ2T by characterizing its genome structure, gene content and phylogenetic placement. Our detailed case study will contribute to our overall understanding of why Natrinema strains can survive in such a high-altitude salt lake.

Complete genome sequence of esterase-producing bacterium Croceicoccus marinus E4A9T.

Croceicoccus marinus E4A9Twas isolated from deep-sea sediment collected from the East Pacific polymetallic nodule area. The strain is able to produce esterase, which is widely used in the food, perfume, cosmetic, chemical, agricultural and pharmaceutical industries. Here we describe the characteristics of strain E4A9, including the genome sequence and annotation, presence of esterases, and metabolic pathways of the organism. The genome of strain E4A9T comprises 4,109,188 bp, with one chromosome (3,001,363 bp) and two large circular plasmids (761,621 bp and 346,204 bp, respectively). Complete genome contains 3653 coding sequences, 48 tRNAs, two operons of 16S-23S-5S rRNA gene and three ncRNAs. Strain E4A9T encodes 10 genes related to esterase, and three of the esterases (E3, E6 and E10) was successfully cloned and expressed in Escherichia coli Rosetta in a soluble form, revealing its potential application in biotechnological industry. Moreover, the genome provides clues of metabolic pathways of strain E4A9T, reflecting its adaptations to the ambient environment. The genome sequence of C. marinus E4A9T now provides the fundamental information for future studies.

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.

Structural insights of a hormone sensitive lipase homologue Est22.

Hormone sensitive lipase (HSL) catalyzes the hydrolysis of triacylglycerols into fatty acids and glycerol, thus playing key roles in energy homeostasis. However, the application of HSL serving as a pharmaceutical target and an industrial biocatalyst is largely hampered due to the lack of high-resolution structural information. Here we report biochemical properties and crystal structures of a novel HSL homologue esterase Est22 from a deep-sea metagenomic library. Est22 prefers short acyl chain esters and has a very high activity with substrate p-nitrophenyl butyrate. The crystal structures of wild type and mutated Est22 with its product p-nitrophenol are solved with resolutions ranging from 1.4 Å to 2.43 Å. The Est22 exhibits a α/ß-hydrolase fold consisting with a catalytic domain and a substrate-recognizing cap domain. Residues Ser188, Asp287, and His317 comprise the catalytic triad in the catalytic domain. The p-nitrophenol molecule occupies the substrate binding pocket and forms hydrogen bonds with adjacent residues Gly108, Gly109, and Gly189. Est22 exhibits a dimeric form in solution, whereas mutants D287A and H317A change to polymeric form, which totally abolished its enzymatic activities. Our study provides insights into the catalytic mechanism of HSL family esterase and facilitates the understanding for further industrial and biotechnological applications of esterases.

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.

Draft Genome Sequence of Altererythrobacter marensis DSM 21428T, Isolated from Seawater.

Altererythrobacter marensis DSM 21428(T) was isolated from seawater collected around Mara Island, South Korea. The genomic characteristics of this strain support its potential for alkane-related compound degradation. A. marensis DSM 21428(T) has potential applications in bioremediation projects concerning offshore petroleum spill prevention and response.

Complete genome sequence of a benzo[a]pyrene-degrading bacterium Altererythrobacter epoxidivorans CGMCC 1.7731(T).

Altererythrobacter epoxidivorans CGMCC 1.7731(T) is a Gram-negative bacterium isolated from marine sediments. It is able to utilize benzo[a]pyrene as sole carbon and energy source. Here, we describe the complete genome sequence and annotation of A. epoxidivorans CGMCC 1.7731(T). The genome has a size of 2,786,256 bp (61.50 mol% G+C content), which consists of 2773 coding genes, 43 tRNA genes and 3 rRNA genes. According to the genome information, strain A. epoxidivorans CGMCC 1.7731(T) encodes 22 genes related to degradation of benzo[a]pyrene. These genes may have potential in bioremediation of PAH-polluted environments.

Complete genome sequence of the heavy metal resistant bacterium Altererythrobacter atlanticus 26DY36(T), isolated from deep-sea sediment of the North Atlantic Mid-ocean ridge.

Altererythrobacter atlanticus 26DY36(T) (CGMCC 1.12411(T)=JCM 18865(T)) was isolated from the North Atlantic Mid-Ocean Ridge. The strain is resistant to heavy metals, such as Mn(2+) (200 mM), Co(2+) (2.0mM), Cu(2+) (1mM), Zn(2+) (1mM), Hg(2+) (0.1mM) and Cd(2+) (0.5mM). Here we describe the genome sequence and annotation, as well as the features of the organism. A. atlanticus 26DY36(T) harbors a chromosome (3,386,291 bp) and a circular plasmid (88,815 bp). The genome contains 3322 protein-coding genes (2483 with predicted functions), 47 tRNA genes and 6 rRNA genes. A. atlanticus 26DY36(T) encodes dozens of genes related to heavy metal resistance and has potential applications in the bioremediation of heavy metal-contaminated environments.

Draft Genome Sequence of Thermophilic Exiguobacterium sp. Strain JLM-2, Isolated from Deep-Sea Ferromanganese Nodules.

Exiguobacterium sp. strain JLM-2 is a thermophilic bacterium isolated from deep-sea ferromanganese (FeMn) nodules. The estimated genome of this strain is 2.9 Mb, with a G+C content of 48.32%. It has a novel circular 15,570-bp plasmid. The draft genome sequence may provide useful information about Mn-microbe interactions and the genetic basis for tolerance to environment stresses.

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)).