Phenotypic and genotypic characterization of Marinobacterium weihaiense sp. nov. and Marinobacterium marinum sp. nov., isolated from marine sediment, and genomic properties of the genus Marinobacterium.

In this study, two novel bacterial strains were isolated from coastal sediment of Weihai, China. The two strains were Gram-stain-negative and facultatively aerobic, designated 3-1745T and A346T. Based on phenotypic, genetic and phylogenetic properties, strains 3-1745T and A346T represent two novel species of the genus Marinobacterium. The results of genome analysis revealed many central carbohydrate metabolism pathways such as gluconeogenesis, pyruvate oxidation, tricyclic acid cycle, pentose phosphate pathway and PRPP biosynthesis in the genus Marinobacterium. The ability of strains 3-1745T and A346T to utilize volatile fatty acids was experimentally confirmed. Polyhydroxyalkanoate synthases (PhaA, PhaB and PhaC) for the synthesis of polyhydroxyalkanoates were prevalent in the genus Marinobacterium. Multiple BGCs (biosynthetic gene clusters) including betalactone, ectoine, ranthipeptide, redox-cofactor, RiPPs (ribosomally synthesized post-translationally modified peptides) and T3PKS (polyketide synthases) in the genome of the genus Marinobacterium were found. Additional genome analyses suggested that the genus Marinobacterium contained diverse potential mechanisms of salt tolerance and mainly utilized oligosaccharides. This is the first report on broad genomic analyses of the genus Marinobacterium with the description of two novel species and potential ecological and biotechnological implications.

Fulvivirga sedimenti sp.nov, isolated from the sediment of oceanic tidal zone.

A yellow-orange, rod-shaped (0.3-0.4 × 2.2-3.8 µm), Gram-stain-negative, non-motile, atrichous bacterium, designated strain 1062T, was isolated from tidal zone sediment collected from Xiaoshi Island, Weihai, Shandong Province, China. Growth of strain 1062T occurred at 15-43 °C (optimum, 37 °C), pH 6.0-9.5 (optimum, pH 7.5) and with 0.5-7.0% (w/v) NaCl (optimum, 2.0-3.0%). Nitrate was not reduced to nitrite or nitrogen. Positive for catalase and oxidase activity, as well as the hydrolysis of casein, DNA, starch and Tweens 20, 40, 60, but negative for hydrolysis of alginate, CM-cellulose, agar and Tweens 80. The 16S rRNA gene sequence comparisons indicated that strain 1062T had a sequence similarity of 96.2% with Fulvivirga lutimaris KCTC 42720T and 94.3% with Fulvivirga kasyanovii KCTC 12832T. Phylogenetic analysis showed that strain 1062T belonged to the genus Fulvivirga. The genomic DNA G + C content was 45.1 mol%. The ANI values of strain 1062T in comparison to F. kasyanovii KCTC 12832T and F. lutimaris KCTC 42720T were all lower than 70%. The dDDH values of strain 1062T in comparison to F. kasyanovii KCTC 12832T and F. lutimaris KCTC 42720T were all lower than 20%. The average amino acid identity values of strain 1062T in comparison to F. kasyanovii KCTC 12832T and F. lutimaris KCTC 42720T were all lower than 60%. The major fatty acids (> 5%) of strain 1062T were iso-C15:0, iso-C15:0 G, iso-C15:0 3OH, iso-C17:0 3-OH and summed feature 3 (C16:1ω7c/C16:1ω6c). The polar lipids consist of an aminolipid, phosphatidylethanolamine, phosphatidyglycerol and diphosphatidylglycerol. The major respiratory quinone was MK-7. Based on the results of physiological, biochemical and chemotaxonomic characteristics, the strain 1062T (= KCTC 72868T = MCCC 1H00499T) was identified as a new species of the genus Fulvivirga and the name Fulvivirga sedimenti sp. nov, is proposed.

Description and Genomic Characterization of Oceaniferula flavus sp. nov., a Novel Potential Polysaccharide-Degrading Candidate of the Difficult-to-Cultivate Phylum Verrucomicrobiota Isolated from Seaweed.

A novel strain, isolate 5K15T, which belongs to difficult-to-cultivate phylum Verrucomicrobiota, was recovered from kelp collected from Li Island, Rongcheng, China. The genome sequence of the strain (genome size 3.95 Mbp) showed the presence of four putative biosynthetic gene clusters (BGCs), namely, two terpene biosynthetic gene clusters, one aryl polyene biosynthetic cluster, and one type III PKS cluster. Genomic analysis revealed 79 sulfatase-encoded genes, 24 sulfatase-like hydrolase/transferase-encoded genes, and 25 arylsulfatase-encoded genes, which indicated the great potential of 5K15T to degrade sulfated polysaccharides. Comparative analysis of 16S rRNA gene sequence showed that the novel strain was most closely related to Oceaniferula marina N1E253T (96.4%). On the basis of evidence from a polyphasic study, it is proposed that the strain 5K15T (= KCTC 82748T = MCCC 1H00442T = SDUM 810003T) be classified as Oceaniferula flavus sp. nov. The strain has the ability of carbohydrate transport and metabolism. This ability allows it to survive in carbohydrate-rich materials such as kelp. It has the potential to be used in the marine drug industry using seaweed.

Maribellus maritimus sp. nov., isolated from marine sediment.

A novel facultatively anaerobic and Gram-stain-negative bacterial strain, designated 5E3T, was isolated from intertidal sediments of Xiaoshi Island of Weihai, People's Republic of China. Cells of strain 5E3T were long rod-shaped with widths of 0.3-0.5 µm and lengths of 4.0-6.0 µm. Optimum growth of strain 5E3T occurred at 33 °C, pH 6.5-7.0 and with 3% (w/v) NaCl. Oxidase activity was negative but catalase activity was weakly positive. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strain 5E3T was most closely related to 'Maribellus comscasis' WC007 (99.5%), followed by M. sediminis MCCC 1K04285T (95.9%) and M. luteus XSD2T (95.6%). Genome comparisons between strain 5E3T and strain 'M. comscasis' WC007, using average nucleotide identity (ANI) value (93.0%) and DNA-DNA hybridization (DDH) value (50.1%), confirmed low genome relatedness. The major cellular fatty acids (≥ 10%) were iso-C15:0 and iso-C17:0 3-OH. The sole respiratory quinone was MK-7. The polar lipids consisted of phosphatidylethanolamine (PE), one unidentified aminolipid (AL) and three unidentified lipids (L1, L2, L3). The DNA G + C content was 37.9 mol%. According to the integrated results of phylogenetic, physiological, biochemical and chemotaxonomic characteristics, we propose that strain 5E3T represents a novel species of the genus Maribellus, for which the name Maribellus maritimus sp. nov. is proposed. The type strain is 5E3T (= KCTC 82744T = MCCC 1H00473T).