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

Marinobacter albus sp. nov., Isolated from Sand Sediment in a Coastal Intertidal Zone

A Gram-stain-negative bacterium with a rod-to-ovoid shape, named strain M216T, was isolated from sand sediment from the coastal intertidal zone of Huludao, Liaoning Province, China. Growth was observed at 8-40 °C (optimal, 30 °C), pH 5.5-9.5 (optimal, pH 6.5) and 0.5-14.0% (w/v) NaCl (optimal, 6%). Strain M216T possessed ubiquinone-9 as its sole respiratory quinone and phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, one unidentified aminophosphoglycolipid, one unidentified aminophospholipid, two unidentified phosphoglycolipids, three unidentified phospholipids and three unidentified glycolipids as the main polar lipids. C12:0, C16:0, C12:0 3-OH, C16:1 ω9c, C18:1 ω9c and summed features 3 (C16:1 ω7c and/or C16:1 ω6c) were the major fatty acids (> 5%). The 16S rRNA gene sequence of strain M216T exhibited high similarity to those of 'Marinobacter arenosus' CAU 1620T and Marinobacter adhaerens HP15T (99.3% and 98.5%, respectively) and less than 98.5% similarity to those of the other type strains. The ANI and dDDH values between the strain M216T and 'Marinobacter arenosus' CAU 1620T were 87.4% and 33.3%, respectively; these values were the highest among the other type strains but lower than the species threshold. The G+C content of strain M216T was 58.3%. Genomic analysis revealed that strain M216T harbors the major CAZymes of GH13, GH23, GH73, and PL5, which are responsible for polysaccharide degradation and the potential ability to reduce nitrate to ammonia. Through phenotypic, genotypic, and chemotaxonomic analyses, we proposed the name Marinobacter albus sp. nov., a novel species in the genus Marinobacter, with its type strain M216T (= MCCC 1K08600T = KCTC 82894T).

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

Two moderately halotolerant bacterium strains, designated PJ-16^T and PJ-38, were isolated from a tidal flat of the red beach in Panjin City, Liaoning Province, PR China. Cells were found to be Gram-stain-negative, aerobic, motile, rod-shaped with a single polar flagellum. Optimum growth of strain PJ-16^T occurred at 30 °C, pH 7.0 and 0.2-8.0  % (w/v) NaCl, and strain PJ-38 at 30 °C, pH 6.0-7.0 and 0.2-8.0  % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain PJ-16^T was most closely related to Marinobacter denitrificans KCTC 62941^T (99.2 % 16S rRNA gene sequence similarity), Marinobacter algicola DSM 16394^T (98.6 %), Marinobacter salarius JCM 19399^T (98.4 %) and Marinobacter confluentis KCTC 42705^T (98.2 %), and strain PJ-38 was most closely related to M. denitrificans KCTC 62941^T (99.1 %), M. algicola DSM 16394^T (98.6 %), M. salarius JCM 19399^T (98.4 %) and M. confluentis KCTC 42705^T (98.1 %). The G+C content of the genomic DNA of strain PJ-16^T based on its draft genomic sequence was 57.4 mol%. The major cellular fatty acids of strain PJ-16^T were C_16 : 0, C_16 : 1  ω7c/C_16 : 1  ω6c and C_18 : 1  ω9c. The major respiratory quinone of PJ-16^T was ubiquinone-9 and the major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The results of the phenotypic, phylogenetic and genomic analyses revealed that strains PJ-16^T and PJ-38 represent a novel species of the genus Marinobacter, and the name Marinobacter panjinensis sp. nov. is proposed. The type strain is PJ-16^T (= CGMCC 1.13694^T= KCTC 72023^T).

Marinobacter mangrovi sp. nov., isolated from mangrove sediment

A novel marine bacterium, designated strain CHFG3-1-5^T, was isolated from mangrove sediment sampled at Jiulong River estuary, Fujian, PR China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CHFG3-1-5^T belonged to the genus Marinobacter, with the highest sequence similarity to Marinobacter segnicrescens SS011B1-4^T (97.6%), followed by Marinobacter nanhaiticus D15-8W^T (97.5%), Marinobacter bohaiensis T17^T (97.1%) and Marinobacter hydrocarbonoclasticus SP.17^T (90.6%). The bacterium was Gram-stain-negative, facultative anaerobic, oxidase- and catalase-positive, rod-shaped and motile with a polar flagellum. Strain CHFG3-1-5^T 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 C_{16 : 0}, summed feature 3 (C_{16 : 1} ω7c/ω6c), C_{12 : 0}, summed feature 9 (C_{17 : 1} iso ω9c and/or C_{16 : 0} 10-methyl), C_{12 : 0} 3-OH and summed feature 8 (C_{18 : 1} ω7c and/or C_{18 : 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 CHFG3-1-5^T 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 CHFG3-1-5^T was able to oxidise iron. The combined genotypic and phenotypic data showed that strain CHFG3-1-5^T represents a novel species within the genus Marinobacter, for which the name Marinobacter mangrovi sp. nov. is proposed, with the type strain CHFG3-1-5^T (=MCCC 1A18306^T=KCTC 82398^T).

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 changyiensis, sp. nov., isolated from offshore sediment

An aerobic, Gram-stain-negative bacterium, designated CLL7-20^T, was isolated from a marine sediment sample from offshore of Changyi, Shandong Province, China. Cells of strain CLL7-20^T 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 CLL7-20^T were C_16 : 0 and summed feature 3 (C_16 : 1 ω7c/C_16 : 1 ω6c). The main polar lipids of strain CLL7-20^T were phosphatidylethanolamine (PE), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG) and an unidentified aminolipid (AL). Strain CLL7-20^T contained Q-9 as the major respiratory quinone. The G+C content of its genomic DNA was 56.2 mol%. Phylogenetically, strain CLL7-20^T branched within the genus Marinobacter, with M. daqiaonensis YCSA40^T being its closest phylogenetic relative (96.7 % 16S rRNA gene sequence similarity), followed by M. sediminum R65^T (96.6 %). Average nucleotide identity and in silico DNA-DNA hybridization values between strain CLL7-20^T 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 CLL7-20^T (=MCCC 1A14855^T=KCTC 72664^T) 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 CLL7-20^T, which indicate its potential as a promising alternative to chemical fertilizers in iron-limitated environments such as saline soils.

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

A novel bacterium, designated JB02H27^T, 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 JB02H27^T consistently fell within the genus Marinobacter and formed a clade together with Marinobacter algicola DG893^T (98.8 % similarity), Marinobacter confluentis KCTC 42705^T (98.4 %), Marinobacter salarius R9SW1^T (98.4%) and Marinobacter halotolerans CP12^T (97.9 %), which were subsequently used as reference strains for comparisons of phenotypic and chemotaxonomic characteristics. Average nucleotide identity values between strain JB02H27^T 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, C_16 : 0, C_18 : 1 ω9c and C_16 : 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 JB02H27^T represents a novel species of the genus Marinobacter, for which the name Marinobacter denitrificans sp. nov. is proposed. The type strain is JB02H27^T (=GDMCC 1.1528^T=KCTC 62941^T).