Marinobacter sediminicola sp. nov. and Marinobacter xiaoshiensis sp. nov., Isolated from Coastal Sediment.

Two Gram-stain-negative, facultative anaerobic, rod-shaped, motile bacterial strains, designated F26243T and F60267T were isolated from coastal sediment in Weihai, China. Strains F26243T and F60267T were grown at 4-40 °C (optimum 33 °C), pH 7.0-9.5 and pH 6.5-9.5 (optimum at pH 7.0), in the presence of 1.0-7.0% (w/v) NaCl (optimum 2.5%) and 1.0-12.0% (w/v) NaCl (optimum 2.0%), respectively. The 16S rRNA gene sequences phylogenetic analysis showed that strains F26243T and F60267T are closely related to the genus Marinobacter and exhibited the highest sequence similarities to Marinobacter salexigens HJR7T (97.7% and 98.0%, respectively), the similarity between two isolates was 96.7%. Strains F26243T and F60267T displayed genomic DNA G + C content of 53.6% and 53.8%, respectively. When compared to the M. salexigens HJR7T, the average nucleotide identity (ANI) values were 83.7% and 84.1%, and the percentage of conserved proteins (POCP) values were 79.9% and 84.6%, respectively. Ubiquinone 9 (Q-9) was the only respiratory quinone detected in both isolates. The major cellular fatty acids (> 10.0%) were summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c), C16:0 and C18:1ω9c. The polar lipid profiles of strains F26243T and F60267T contained diphosphatidylglycerol, phosphatidylethanolamine, phosphatidyldimethylethanolamine, phosphatidylglycerol, aminophospholipid and one unidentified phospholipid. Based on genomic characteristics, phenotypic and chemotaxonomic, strains F26243T and F60267T represent two novel species of the genus Marinobacter, for which the names Marinobacter sediminicola sp. nov. and Marinobacter xiaoshiensis sp. nov. are proposed, the type strains are F26243T (= KCTC 92640T = MCCC 1H01345T) and F60267T (= KCTC 92638T = MCCC 1H01346T).

The Description of Pseudoalteromonas apostichopi sp. nov., Vibrio apostichopi sp. nov., and Marinobacter apostichopi sp. nov. from the Fertilized Eggs and Larvae of Apostichopus japonicus.

Three novel bacterial strains, FE4T, FE10T, and LA51T, which are phylogenetically affiliated to the genera Pseudoalteromonas, Vibrio, or Marinobacter, respectively, isolated from fertilized eggs and juveniles of sea cucumber Apostichopus japonicus were characterized by a genome-based taxonomical approach including multilocus sequence analysis (MLSA) combined with classical phenotypic and chemotaxonomic characterizations. A molecular network reconstructed on the basis of nucleotide sequences of four phylogenetic maker protein genes revealed that the strains FE4T, FE10T, and LA51T were closely related to Pseudoalteromonas shioyasakiensis, Vibrio lentus, and Marinobacter similis, respectively. Average nucleotide identity (ANI) comparisons against phylogenetically related species to FE4T, FE10T, and LA51T demonstrated that each newly described strain could not be identified as any previously described species within each genus showing < 95% ANI: 91.3% of FE4T against P. shioyasakiensis JCM 18891 T, 92.6% of FE10T against "V. bathopelagicus" Sal10, and 92.6% of LA51T against M. similis A3d10T, in maximum, respectively. Here, we show molecular phylogenetic, genomic, phenotypic, and chemotaxonomic features of the newly described species FE4T, FE10T, and LA51T. We also propose Pseudoalteromonas apostichopi sp. nov. with FE4T (JCM 36173 T = LMG 33143 T) as the type strain, Vibrio apostichopi sp. nov. with FE10T (JCM 36174 T = LMG 33144 T) as the type strain, and Marinobacter apostichopi sp. nov. with LA51T (JCM 36175 T = LMG 33145 T) as the type strain.

Marinobacter mangrovi sp. nov., isolated from mangrove sediment.

A novel marine bacterium, designated strain CHFG3-1-5T, was isolated from mangrove sediment sampled at Jiulong River estuary, Fujian, PR China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CHFG3-1-5T belonged to the genus Marinobacter, with the highest sequence similarity to Marinobacter segnicrescens SS011B1-4T (97.6%), followed by Marinobacter nanhaiticus D15-8WT (97.5%), Marinobacter bohaiensis T17T (97.1%) and Marinobacter hydrocarbonoclasticus SP.17T (90.6%). The bacterium was Gram-stain-negative, facultative anaerobic, oxidase- and catalase-positive, rod-shaped and motile with a polar flagellum. Strain CHFG3-1-5T grew optimally at 32-37 °C, pH 6.0-8.0 and in the presence of 2.0-3.0% (w/v) NaCl. The G+C content of the chromosomal DNA was 61.1 mol%. The major respiratory quinone was determined to be Q-9. The principal fatty acids were C16 : 0, summed feature 3 (C16 : 1 ω7c/ω6c), C12 : 0, summed feature 9 (C17 : 1 iso ω9c and/or C16 : 0 10-methyl), C12 : 0 3-OH and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, three phospholipids, one glycolipid and two aminolipids. The average nucleotide identity and digital DNA-DNA hybridization values among the genomes of strain CHFG3-1-5T and the reference strains were 73.4-79.4 and 19.6-22.4%, respectively. Like many other species reported in the genus Marinobacter, strain CHFG3-1-5T was able to oxidise iron. The combined genotypic and phenotypic data showed that strain CHFG3-1-5T represents a novel species within the genus Marinobacter, for which the name Marinobacter mangrovi sp. nov. is proposed, with the type strain CHFG3-1-5T (=MCCC 1A18306T=KCTC 82398T).

Marinobacter nauticus (Baumann et al. 1972) comb. nov. arising from instances of synonymy and the incorrect interpretation of the International Code of Nomenclature of Prokaryotes.

Studies on Pseudomonas nautica Baumann et al. 1972 (Approved Lists 1980) and Marinobacter hydrocarbonoclasticus Gauthier et al. 1992 have shown that they should be treated as heterotypic synonyms. As a consequence, they have been treated as belonging to a single species, Marinobacter hydrocarbonoclasticus Gauthier et al. 1992. This interpretation of the International Code of Nomenclature of Bacteria/Prokaryotes is, however, based on a fundamental flaw in the interpretation of the wording of Rule 15 as documented in the 1975 and 1990 revisions where the wording has been partially corrected in the 2008 revision. A key aspect of the incorrect interpretation is that the nomenclatural type of a taxon, in this case Marinobacter hydrocarbonoclasticus Gauthier et al. 1992 (the nomenclatural type of the Marinobacter Gauthier et al. 1992) must be used instead of recognising the priority of the epithet in Pseudomonas nautica Baumann et al. 1972 (Approved Lists 1980), with the creation of a new combination Marinobacter nauticus (Baumann et al. 1972). It is now clear that there is no justification for that interpretation and it is necessary to create a new combination, Marinobacter nauticus (Baumann et al. 1972) in the situation where Marinobacter hydrocarbonoclasticus Gauthier et al. 1992 and Pseudomonas nautica Baumann et al. 1972 (Approved Lists 1980) are treated as heterotypic synonyms. Additional studies have shown that Marinobacter aquaeolei Nguyen et al. 1993 and Marinobacter hydrocarbonoclasticus Gauthier et al. 1992 should also be treated as heterotypic synonyms.

Marinobacter halodurans sp. nov., a halophilic bacterium isolated from sediment of a salt flat.

A Gram-staining-negative, aerobic, cream-coloured, marine bacterium, with rod-shaped cells, designated strain YJ-S3-2T, was isolated from salt flat sediment of Yongyu-do, Republic of Korea. YJ-S3-2T grew at pH 5.0-9.0 (optimum pH 7.0), 4-45 °C (optimum 30 °C) and with 1-18 % (w/v) NaCl (optimum 6 %). The results of 16S rRNA gene sequence analysis indicated that YJ-S3-2T was closely related to Marinobacter segnicrescens SS011B1-4T (97.0 %) followed by, 'Marinobacter nanhaiticus' D15-8W (96.7 %), Marinobacter bryozoorum 50-11T (96.7 %), Marinobacter koreensis DSMZ 179240T T (96.5 %) and Marinobacter bohaiensis T17T (96.5 %). The average nucleotide identity (ANI) and the genome to genome distance calculator (GGDC) estimate values between YJ-S3-2T and related type strains were 73.7-79.8 and 19.9-22.5 %, and also 73.5 and 20.7 % with Marinobacter hydrocarbonoclasticus. YJ-S3-2T was characterized as having Q-9 as the predominant respiratory quinone and the principal fatty acids (>10 %) were C16 : 0 (22.3 %), summed feature 9 (C17 : 1iso ω9c/C16 : 0 10-methyl, 13.8 %) and 3 (C16 : 1ω7c/C16 : 1ω6c, 11.9 %). The polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, two unidentified aminolipids and two unidentified phospholipids. The DNA G+C content of YJ-S3-2T is 60.9 mol%. On the basis of the polyphasic taxonomic evidence presented in this study, YJ-S3-2T should be classified as representing a novel species within the genus Marinobacter, for which name Marinobacter halodurans sp. nov. is proposed, with the type strain YJ-S3-2T (=KACC 19883T=KCTC 62937T=JCM 33109T).

Marinobacter vulgaris sp. nov., a moderately halophilic bacterium isolated from a marine solar saltern.

A facultatively anaerobic, Gram-stain-negative and non-gliding bacterium, designated F01T, was isolated from marine solar saltern in Weihai, PR China. Cells of F01T were 0.2-0.4 µm wide and 1.4-4.1 µm long, weakly catalase-positive and oxidase-negative. Growth of F01T was determined to occur at 4-40 °C (optimum, 33-37 °C), pH 6.5-8.5 (optimum, 7.0-8.0), and with 0.5-18.0 % (w/v) NaCl (optimum, 3.0-6.0 %). The 16S rRNA gene sequence analysis indicated that F01T represented a member of the genus Marinobacter within the family Alteromonadaceae. Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate was most closely related to Marinobacter algicola DSM 16394T, with a sequence similarity of 97.5 %. The DNA G+C content of the isolate was 57.6 mol%. The major respiratory quinone of F01T was ubiquinone-9 (Q-9) and the major fatty acids were anteiso-C15 : 0, C16 : 0 and C18 : 1ω9c. The major polar lipids were phosphoaminolipid, phosphatidylglycerol and phosphatidylethanolamine. On the basis of the results of the phylogenetic analysis and phenotypic properties, it is concluded that F01T can be considered to represent a novel species in the genus Marinobacter, for which the name Marinobacter vulgaris sp. nov. is proposed. The type strain is F01T (=MCCC 1H00290T=KCTC 52700T).

Marinobacter salinexigens sp. nov., a marine bacterium isolated from hadal seawater of the Mariana Trench.

A Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterium, designated ZYF650T, was isolated from the hadal seawater (9600 m) of the Mariana Trench. Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that ZYF650T formed a lineage within the family Alteromonadaceae that was distinct from the most closely related species Marinobacter mobilis and Marinobacter nitratireducens with 16S rRNA gene sequences similarities of 98.0 and 97.7 %, respectively. Strain ZYF650T showed average nucleotide identity values of 75.7 % with Marinobacter hydrocarbonoclasticus, 73.3 % with Marinobacter mobilis and 79.3 % with Marinobacter nitratireducens, and DNA-DNAhybridization values of 21.5, 21.3 and 22.0 % with M. hydrocarbonoclasticus, M. mobilis and M. nitratireducens, respectively, which were lower than the threshold for species delineation. Strain ZYF650T grew with 0-14 % (w/v) NaCl (optimum, 7-8 %) at a temperature range of 10-45 °C (optimum, 28 °C) and pH 6.0-9.5 (optimum, pH 7.0-8.0). The sole respiratory quinone was ubiquinone-9 (Q-9). The polar lipids in ZYF650T comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, three unidentified polar lipids, two unidentified aminolipids and two phospholipids. The predominant fatty acids (more than 10 % of total fatty acids) were C18 : 1 ω9c (21.9 %), C16 : 0 (21.7 %), C12 : 0 3-OH (14.0 %), C16 : 1 ω9c (13.2 %) and C12 : 0 (12.2 %). The DNA G+C content of strain ZYF650T was 55.6 %. On the basis of polyphasic taxonomic analysis, strain ZY650T is considered to represent a novel specie of the genus Marinobacter in the family Alteromonadaceae, for which the name Marinobacter salinexigens sp. nov. is proposed. The type strain is ZYF650T (=JCM 33013T=MCCC 1K03552T).

Marinobacter denitrificans sp. nov., isolated from marine sediment of southern Scott Coast, Antarctica.

A novel bacterium, designated JB02H27T, was isolated from marine sediment collected from the southern Scott Coast, Antarctica. Cells were Gram-stain-negative, facultatively anaerobic, polar-flagellated and motile rods. Growth occurred at 4-45 °C, at pH 7.0-9.0 and with 3-25 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences showed that strain JB02H27T consistently fell within the genus Marinobacter and formed a clade together with Marinobacter algicola DG893T (98.8 % similarity), Marinobacter confluentis KCTC 42705T (98.4 %), Marinobacter salarius R9SW1T (98.4%) and Marinobacter halotolerans CP12T (97.9 %), which were subsequently used as reference strains for comparisons of phenotypic and chemotaxonomic characteristics. Average nucleotide identity values between strain JB02H27T and the four related type strains were 80.9, 76.6, 81.9 and 76.3 %, respectively. The major fatty acids were summed feature 3, C16 : 0, C18 : 1 ω9c and C16 : 0 N alcohol. The polar lipids included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and an unidentified phospholipid, aminolipid, aminophospholipid and glycolipids. The sole respiratory quinone was ubiquinone-9. The DNA G+C content was 56.9 mol%. Based on the genomic, phylogenetic, phenotypic and chemotaxonomic analysis, we propose that strain JB02H27T represents a novel species of the genus Marinobacter, for which the name Marinobacter denitrificans sp. nov. is proposed. The type strain is JB02H27T (=GDMCC 1.1528T=KCTC 62941T).

Marinobacter fonticola sp. nov., isolated from deep sea cold seep sediment.

In this study, we report a novel Gram-negative bacterium, designated as strain CS412T, isolated from deep-sea sediment collected in a cold seep area of the South China Sea. Growth of strain CS412T occurred at 4-40 °C (optimum, 28 °C), pH 5.0-11.0 (optimum, pH 6.0) and with 0-19 % (w/v) NaCl (optimum, 1-2 %). Phylogenetic analysis based on 16S rRNA gene sequence data indicated that strain CS412T belonged to the genus Marinobacter. The closest phylogenetic neighbours of strain CS412T were Marinobacter pelagius HS225T (96.9 %), Marinobacter szutsaonensis NTU-104T (96.8%), Marinobacter santoriniensis NKSG1T (96.4%) and Marinobacter koreensisdd-M3T (96.3 %). The genomic DNA G+C content of strain CS412T was 58.0 mol%. The principal respiratory quinone was ubiquinone-9 (Q-9). The polar lipids of CS412T contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, aminophospholipidand and four glycolipids. The major fatty acids of CS412T contained cyclo-C19 : 0ω8c, C16 : 0, C18 : 1ω7c and C18 : 1ω7c 11-methyl. The results of phylogenetic, physiological, biochemical and morphological analyses suggested that strain CS412T represents a novel species of the genus Marinobacter, and the name Marinobacter fonticola sp. nov. is proposed with the type species CS412T (=CCTCC AB 2019197T=KCTC 72475T).

Marinobacter changyiensis, sp. nov., isolated from offshore sediment.

An aerobic, Gram-stain-negative bacterium, designated CLL7-20T, was isolated from a marine sediment sample from offshore of Changyi, Shandong Province, China. Cells of strain CLL7-20T were rod-shaped, motile with one or more polar flagella, and grew optimally at pH 7.0, at 28 °C and with 3 % (w/v) NaCl. The principal fatty acids of strain CLL7-20T were C16 : 0 and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c). The main polar lipids of strain CLL7-20T were phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG) and an unidentified aminolipid (AL). Strain CLL7-20T contained Q-9 as the major respiratory quinone. The G+C content of its genomic DNA was 56.2 mol%. Phylogenetically, strain CLL7-20T branched within the genus Marinobacter, with M. daqiaonensis YCSA40T being its closest phylogenetic relative (96.7 % 16S rRNA gene sequence similarity), followed by M. sediminum R65T (96.6 %). Average nucleotide identity and in silico DNA-DNA hybridization values between strain CLL7-20T and the closest related reference strains were 73.2% and 19.8 %, respectively. On the basis of its phenotypic, phylogenetic and chemotaxonomic characteristics, we suggest that strain CLL7-20T (=MCCC 1A14855T=KCTC 72664T) is the type strain of a novel species in the genus Marinobacter, for which the name Marinobacter changyiensis sp. nov. is proposed. Based on the genomic analysis, siderophore genes were found from strain CLL7-20T, which indicate its potential as a promising alternative to chemical fertilizers in iron-limitated environments such as saline soils.

Marinobacter maroccanus sp. nov., a moderately halophilic bacterium isolated from a saline soil.

During the taxonomic investigation of exopolymer-producing halophilic bacteria, a rod-shaped, motile, Gram-stain-negative, halophilic bacterium, designated strain N4T, was isolated from a saline soil located in northern Morocco. Optimal growth of the isolate was at 30-37 ºC and at pH 7.0-8.0, in the presence of 5-7 % (w/v) NaCl. Useful characteristics for the phenotypic differentiation of strain N4T from other Marinobacter species included α-chymotrypsin and α-glucosidase activities and the carbohydrate assimilation profile. The major fatty acids detected in strain N4T were C16:0 and C18:1ω9c and the predominant respiratory quinone was ubiquinone-9. Sequence analysis of the 16S rRNA gene indicated that strain N4T belonged to the genus Marinobacter and was closely related to the type strains of Marinobacter adhaerens (99.04 % similarity), Marinobacter salsuginis (98.97 %) and Marinobacter flavimaris (98.36 %). Phylogenetic analysis of the rpoD gene sequence also showed that the nearest neighbours of strain N4T were M. salsuginis (91.49 % similarity), M. adhaerens and M. flavimaris (90.63 %). Strain N4T showed 87.98 % average nucleotide identity with M. flavimaris and M. salsuginis, and 87.47 % with M. adhaerens. Regarding in-silico genome-to-genome distance, strain N4T showed DNA-DNA hybridization values of 33.30 % with M. adhaerens, 34.60 % with M. flavimaris and 34.70 % with M. salsuginis. The DNA G+C content of strain N4T was 57.3 mol%. Based on the results of phenotypic characterization, phylogenetic analysis and genome comparison, strain N4T represents a novel species of the genus Marinobacter, for which the name Marinobacter maroccanus sp. nov. is proposed. The type strain is N4T (=CECT 9525T=LMG 30466T).

Marinobacter profundi sp. nov., a slightly halophilic bacterium isolated from a deep-sea sediment sample of the New Britain Trench.

A piezotolerant, cold-adapted, slightly halophilic bacterium, designated strain PWS21T, was isolated from a deep-sea sediment sample collected from the New Britain Trench. Cells were observed to be Gram-stain negative, rod-shaped, oxidase- and catalase-positive. Growth of the strain was observed at 4-45 °C (optimum 37 °C), at pH 5.0-9.0 (optimum 7.0) and in 0.5-20% (w/v) NaCl (optimum 3-4%). The optimum pressure for growth was 0.1 MPa (megapascal) with tolerance up to 70 MPa. 16S rRNA gene sequence analysis showed that strain PWS21T is closely related to Marinobacter guineae M3BT (98.4%) and Marinobacter lipolyticus SM19T (98.2%). Multilocus sequence analysis (MLSA) based on sequences of housekeeping genes gyrB, recA, atpD, rpoB and rpoD indicates that strain PWS21T represents a distinct evolutionary lineage within the genus Marinobacter. Furthermore, strain PWS21T showed low ANI and diDDH values to the closely related species. The principal fatty acids were identified as C12:0, C12:0 3-OH, C16:1ω9c, C16:0 and C18:1ω9c. Ubiquinone-9 was identified as the major respiratory quinone. The polar lipids were identified as phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), aminophospholipid (APL), two unidentified lipids and an unidentified phospholipid (PL). The G + C content of the genomic DNA was determined to be 60.3 mol%. On the basis of phenotypic, chemotaxonomic and molecular data, we conclude that strain PWS21T represents a novel species of the genus Marinobacter, for which the name Marinobacter profundi sp. nov. is proposed (type strain PWS21T = KCTC 52990T = MCCC 1K03345T).

Marinobacter fuscus sp. nov., a marine bacterium of Gammaproteobacteria isolated from surface seawater.

A Gram-stain-negative bacterium, designated NH169-3T, was isolated from a surface seawater sample of the South China Sea and subjected to a taxonomic polyphasic investigation. Strain NH169-3T was strictly aerobic, non-motile, non-spore-forming and rod-shaped. The colony was 1.0-2.0 mm in diameter after the growth on marine agar at 30 °C for 72 h. The centre of the colony was smooth, circular, convex and brown with a transparent periphery. Strain NH169-3T was able to grow at temperatures between 4-40 °C (optimum, 37 °C), pH 5.5-9.0 (pH 7.5) and with 0-12.5 % (w/v) NaCl (3.0 %). Chemotaxonomic analysis showed that the sole respiratory quinone of strain NH169-3T was ubiquinone 9; major fatty acids were C16 : 0 and C18 : 1ω9c, and major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and one unidentified glycolipid. The DNA G+C content was 52.7 mol%. The comparison of 16S rRNA gene sequences showed that strain NH169-3T was closely related to Marinobacter shengliensis SL013A34A2T with a similarity of 98.0 %. Three phylogenetic trees reconstructed with neighbour-joining, maximum-parsimony and maximum-likelihood methods using 16S rRNA gene sequences showed that strain NH169-3T was grouped into a separated branch with M. shengliensis SL013A34A2T in a clade of the genus Marinobacter and closely related to Marinobacter halophilus JCM 30472T, Marinobacter vinifirmus DSM 17747T and Marinobacter hydrocarbonoclasticus DSM 8798T. Analyses of both phenotypic and phylogenetic properties have suggested that strain NH169-3T was distinctive from species with validly published names in genus Marinobacter. Thus, strain NH169-3T (=MCCC 1K03455T=KCTC 62226T) is proposed as a novel species in genus Marinobacter with the name Marinobacter fuscus sp. nov.

Marinobacter bohaiensis sp. nov., a moderate halophile isolated from benthic sediment of the Bohai Sea.

A Gram-stain-negative, motile, aerobic and rod-shaped bacterial strain, designated T17T, was isolated from benthic sediment sampled at Jiaozhou Bay, Bohai Sea, China, and its taxonomic position was investigated. The 16S rRNA gene sequence of strain T17T exhibited the highest similarity values to those of the type strain Marinobacter lacisalsi FP2.5 (96.2 %) and Marinobacter koreensis DD-M3T (96.2 %). Strain T17T grew optimally at 35 °C, pH 7.0-8.0 and in the presence of 6.0-10.0 % (w/v) NaCl. The predominant ubiquinone in strain T17T was identified as Q-9. The major fatty acids of strain T17T were C12 : 0, C16 : 0 and C16 : 0 10-CH3. The major polar lipids of strain T17T were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidglycerol, an unidentified aminolipid and an unidentified phospholipid. The DNA G+C content of strain T17T was 63.0 mol%. The draft genome sequence of strain T17T includes 4 755 891 bp in total (N50=2 856 325 bp) with a medium read coverage of 100.0x and 11 scaffolds. In silico DNA-DNA hybridization with the three type strains showed 20.3, 19.7 and 19.9 % relatedness to Marinobacter santoriniensis NKSG1T, Marinobacter segnicrescens SS11B1-4T and Marinobacter daqiaonensis CGMCC 1.9167T, respectively. On the basis of the phenotypic, phylogenetic, genomic and chemotaxonomic properties, strain T17T is considered to represent a novel species within the genus Marinobacter, for which the name Marinobacterbohaiensis sp. nov. is proposed. The type strain is T17T (=KCTC 52710T=MCCC 1K03282T).

A non-toxic microbial surfactant from Marinobacter hydrocarbonoclasticus SdK644 for crude oil solubilization enhancement.

This study aims to investigate the ability of a biosurfactant produced by Marinobacter hydrocarbonoclasticus strain SdK644 isolated from hydrocarbon contaminated sediment to enhance the solubilization rate of crude oil contaminated seawater. Phylogenetic analysis shows that strain SdK644 was very closely related to M. hydrocarbonoclasticus with 16S rRNA gene sequence similarity of 97.44%. Using waste frying oil as inducer carbon source, the producing biosurfactant by strain SdK644 was applied to improve crude oil solubilization in seawater. The preliminary characterization of the produced biosurfactant by FT-IR analysis indicates its possible classification in a glycolipids group. Results from crude oil solubilization assay showed that SdK644 strain biosurfactant was 2-fold greater than Tween 80 surfactant in crude oil solubilization and 12-fold higher than seawater control, as shown by GC-MS analysis of aliphatic compounds. Furthermore, this bioactive compound was shown to be nontoxic against Artemia larvae in short-term acute toxicity bioassay. Generally, the results showed the possible use of M. hydrocarbonoclasticus strain SdK644 biosurfactant in bioremediation processes of the marine environments.

Changes in morphology and metabolism enable Mn-oxidizing bacteria from mid-oceanic ridge environment to counter metal-induced stress.

Mn-oxidizing potential of two metal-tolerant bacterial strains - Halomonas meridiana and Marinobacter algicola isolated from the South West Indian Ridge waters were compared at varying concentrations of Mn (II), i.e., 1, 10, and 100 µmol and mmol L-1 . Accompanying changes in their morphology and metabolism were also determined. At concentrations >1 mmol L-1 Mn (II), Mn-oxidizing potential of M. algicola was 2-7 times greater than that of H. meridiana. Scanning electron microscopy revealed that exposure to elevated metal content prompted bacterial cells especially those of M. algicola to been enveloped in exopolymeric material and form aggregates. Energy dispersive spectrometric analysis showed that exopolymeric material acts as a nucleation site for Mn deposition and oxide formation which occurs in the form of microspherical aggregates. These features show striking resemblance to biogenically produced Fe-Mn oxide deposits from Lau Basin. Surprisingly, diffractograms of auto-oxidized and bacterially formed Mn-oxide showed similarities to the hydrothermal vein mineral Rhodochrosite indicating that it can also be produced biotically. Elongation of cells by up to 4× the original size and distortion in cell shape were evident at Mn (II) concentrations >100 µmol L-1 . Marked differences in C-substrate utilization by the test strains were also observed in presence of Mn (II). A shift in use of substrates that are readily available in oceanic waters like N-acetyl-d-glucosamine to those that can be used under changing redox conditions (d-cellobiose) or in the presence of metal ions (d-arabinose, l-asparagine) were observed. These findings highlight the significant role of autochthonous bacteria in transforming reduced metal ions and aiding in the formation of metal oxides. Under natural or laboratory conditions, the mode of bacterially generated Mn-oxide tends to remain the same.

Marinobacter aquaticus sp. nov., a moderately halophilic bacterium from a solar saltern.

A moderately halophilic bacterium designated strain M6-53T was isolated from water of a pond from a marine saltern located in Huelva, south-west Spain. Cells of the strain were Gram-stain-negative, strictly aerobic, motile, slightly curved rods, able to grow in media containing 5-25 % (w/v) NaCl (optimal growth at 10 %, w/v), at temperatures from 20 to 40 °C (optimally at 37 °C) and at pH 6.5-9 (optimally at pH 7.0). Phylogenetic analysis based on 16S rRNA gene sequences placed the new isolate within the genus Marinobacter, with the type strains of the most closely related species being Marinobacter persicus IBRC-M 10445T (98.5 % similarity), Marinobacter oulmenensis Set74T (97.2 %) and Marinobacter hydrocarbonoclasticus ATCC 49840T (97.1 %). The major fatty acids present in strain M6-53T were C18 : 1ω9c (29.5 %), C16 : 0 (26.7 %), C12 : 0 3-OH (15.1 %), C18 : 0 (10.2 %) and C16 : ω9c (9.6 %). The G+C content of the genomic DNA for this strain was determined to be 56.4 mol%. The DNA-DNA hybridization values between strain M6-53T and M. persicus CECT 7991T, M. oulmenensis CECT 7499T and M. hydrocarbonoclasticus DSM 50418 were 8, 41 and 38 %, respectively. These values are lower than the accepted 70 % threshold and showed that the new isolate represented a different species within the genus Marinobacter. Phylogenetic analysis based on the 16S rRNA gene sequence and the phenotypic, genotypic and chemotaxonomic features of this new isolate support the placement of strain M6-53T as a representative of a novel species of the genus Marinobacter, for which we propose the name Marinobacter aquaticus sp. nov., with strain M6-53T (=CECT 9228T=LMG 30006T) as the type strain.

Marinobacter salexigens sp. nov., isolated from marine sediment.

A novel bacterium, designated as strain HJR7T, was isolated from a marine sediment sample collected from the coastal area of Weihai, China (121° 57' E, 37° 29' N). Cells were Gram-stain-negative, facultative anaerobic, non-motile and rod-shaped. The temperature, pH and NaCl ranges for growth were determined as 4-40 °C, pH 6.5-9.5 and 0.5-15.0 % (w/v), respectively. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain HJR7T belongs to the genus Marinobacter in the family Alteromonadaceae. The most closely related species were Marinobacter aromaticivorans (97.6 % 16S rRNA gene sequence similarity) and Marinobacter maritimus (97.3 % similarity). Ubiquinone 9 (Q-9) was the only respiratory quinone detected in strain HJR7T. The major fatty acids of strain HJR7T were C12 : 0, C16 : 0, C16 : 0 N alcohol, C18 : 1ω9c and C18 : 3ω6, 9, 12c. The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, and an unidentified phospholipid. The DNA G+C content of strain HJR7T was 53.7 mol%. On the basis of phylogenetic, genotypic, phenotypic, and chemotaxonomic analyses, strain HJR7T represents a novel species within the genus Marinobacter, for which the name Marinobacter salexigens sp. nov. is proposed. The type strain is HJR7T (=KCTC 52545T=MCCC 1H00176T).

Marinobacter salinus sp. nov., a moderately halophilic bacterium isolated from a tidal flat environment.

Two Gram-stain-negative, aerobic, motile, halophilic, rod-shaped bacteria, designated Hb8T and Hb20, were isolated from a tidal flat environment located on the South-West Korean peninsula. The isolates grew at 10-37 °C, at pH 5.0-9.0 and in NaCl concentrations of 0.5-15 % (w/v; optimum, 3.0-6.0 %). Sequence analysis of the 16S rRNA indicated that the isolates belong to the genus Marinobacter and are most closely related to Marinobacter sediminumR65T (98.3 %), followed by Marinobacter lipolyticus SM19T, Marinobacter salsuginis SD-14BT and Marinobacter similis A3d10T. The overall 16S rRNA gene sequence similarity with these species was 97.9 %, but Hb8T and Hb20 showed 100 % sequence similarity with each other. DNA-DNA relatedness values of H8T and Hb20 suggested that these isolates represent a single species, while DNA-DNA relatedness values of the two novel isolates with M. sediminum DSM 27079T and M. similis DSM 15400T were only 21.3 and 22.9 %, respectively. The major fatty acids present in strain Hb8T were identified as C16 : 0, C16 : 1ω9c, C18 : 1ω9c, C18 : 0 3-OH and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). Ubiquinone-9 was the main respiratory quinone in both the novel strains. The polar lipids found to be present included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, four unidentified phospholipids and five unidentified lipids. The genomic DNA G+C content of Hb8T and Hb20 was 54.5 mol%. Polyphasic analysis indicated that the two isolates are representatives of a novel species of the genus Marinobacte, for which the name Marinobacter salinus sp. nov. is proposed. The type strain is Hb8T (=KCTC 52255T=JCM 31416T).

Marinobacter halotolerans sp. nov., a halophilic bacterium isolated from a saltern crystallizing pond.

A Gram-stain-negative, moderately halophilic, motile bacterium, designated strain CP12T, was isolated from a crystallizing pond of a saltern of the Yellow Sea in Korea. Cells of strain CP12T were non-spore-forming rods and produced whitish-yellow colonies. Growth was observed at 10-37 °C (optimum 37 °C), at pH 6.0-9.0 (optimum pH 7.0), and in the presence of 0.5-20 % (w/v) NaCl (optimum 3 %). Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain CP12T was closely related to Marinobacter flavimaris SW-145T (98.4 % 16S rRNA gene sequence similarity), Marinobacter algicola DG893T (98.2 %), Marinobacter adhaerens HP15T (98.2 %), Marinobacter salsuginis SD-14BT (97.9 %), Marinobacter salarius R9SW1T (97.6 %) and Marinobacter lipolyticus SM19T (97.1 %). DNA-DNA hybridization studies showed values lower than 18.6 % between strain CP12T and any of these species. The predominant respiratory isoprenoid quinone was ubiquinone-9 and the major cellular fatty acids of strain CP12T were C16 : 0, C12 : 0 3-OH, C12 : 0, Summed feature 3, C16 : 0 10-methyl and C18 : 1ω9c. On the basis of phenotypic properties, and phylogenetic and chemotaxonomic data, it is evident that strain CP12T represents a novel species of the genus Marinobacter, for which the name Marinobacter halotolerans sp. nov. is proposed. The type strain is CP12T (=KACC 18381T=NBRC 110910T).