Mangrovibacterium marinum sp. nov., isolated from a coastal sediment

Gaoshiqia sediminis gen. nov., sp. nov., isolated from coastal sediment

A Gram-stain-negative, facultative anaerobic, motile, rod-shaped and orange bacterium, designated A06^T, was obtained off the coast of Weihai, PR China. Cells were 0.4-0.5×0.6-1.0 µm in size. Strain A06^T grew at 20-40 °C (optimum, 33 °C), at pH 6.0-8.0 (optimum, pH 6.5-7.0) and in the presence of 0-8 % NaCl (w/v) (optimum, 2 %). Cells were oxidase and catalase positive. Menaquinone-7 was detected as the major respiratory quinone. The dominant cellular fatty acids were identified as C_15:0 2-OH, iso-C_15:0, anteiso-C_15:0 and iso-C_15:1  ω6c. The DNA G+C content of strain A06^T was 46.1 mol%. The polar lipids were phosphatidylethanolamine, one aminolipid, one glycolipid and three unidentified lipids. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain A06^T is a member of the family Prolixibacteraceae and exhibited the highest sequence similarity to Mangrovibacterium diazotrophicum DSM 27148^T (94.3 %). Based on its phylogenetic and phenotypic characteristics, strain A06^T is considered to represent a novel genus in the family Prolixibacteraceae, for which the name Gaoshiqia gen. nov. is proposed. The type species is Gaoshiqia sediminis sp. nov., with type strain A06^T (=KCTC 92029^T=MCCC 1H00491^T). The identification and acquisition of microbial species and genes in sediments will help broaden the understanding of microbial resources and lay a foundation for its application in biotechnology. Strain A06^T uses an enrichment method, so the isolation of strain A06^T is of great significance to the enrichment of marine microbial resources.

Aquipluma nitroreducens gen. nov. sp. nov., a novel facultatively anaerobic bacterium isolated from a freshwater lake

A novel facultatively anaerobic, nitrate-reducing bacterium, designated MeG22^T, was isolated from a freshwater lake in Japan. Cells of the strain were straight rods (0.8×2.5-10 µm), motile, and Gram-stain-negative. For growth, the optimum NaCl concentration was 0 % and the optimum temperature was 30 °C. Under anoxic conditions, strain MeG22^T reduced nitrate to nitrite. Major cellular fatty acids were C_15 : 1 ω6c (13.6 %), C_17 : 0 (11.9 %), anteiso-C_15 : 0 (10.6 %) and iso-C_15 : 0 (10.6 %). The major respiratory quinone was menaquinone-7. The genome sequence of strain MeG22^T consists of 5 712 279 bp with a G+C content of 40.3 mol%. Phylogenetic analysis based on the 16S rRNA gene revealed that the novel strain belonged to the family Prolixibacteraceae within the phylum Bacteroidetes. The closest relative of strain MeG22^T was Sunxiuqinia faeciviva strain JAM-BA0302^T with a 16S rRNA gene sequence similarity of 90.9 %. On the basis of phylogenetic and phenotypic characterization, Aquipluma nitroreducens, gen. nov., sp. nov., belonging to the family Prolixibacteraceae is proposed with the type strain MeG22^T (=NBRC 112896^T=DSM 106262^T).

Mangrovibacterium lignilyticum sp. nov., a facultatively anaerobic lignin-degrading bacterium isolated from mangrove sediment

An alkali lignin-degrading, Gram-stain-negative, rod-shaped, non-motile and facultatively anaerobic bacterium, designated BM_7^T, was isolated from mangrove sediment of the supralittoral zone in the Jiulong river estuary, PR China. The cells of strain BM_7^T were 0.4-0.6 µm wide and 1.0-8.5 µm long. Oxidase and catalase activities were positive. Strain BM_7^T could grow at 10-37 °C (optimum, 25-28 °C), at pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 0.5-6 % (w/v) NaCl (optimum, 2%). Phylogenetic analysis of 16S rRNA gene sequences indicated that strain BM_7^T belonged to the genus Mangrovibacterium of the family Prolixibacteraceae. It showed the highest similarity to Mangrovibacterium diazotrophicum JCM 19152^T (96.8 %), followed by Mangrovibacterium marinum KCTC 42253^T (96.1%). The values of average nucleotide identity and DNA-DNA hybridization were calculated as 76.9, 24.3 and 76.1, 17.4 % between strain BM_7^T with M. diazotrophicum JCM 19152^T and M. marinum KCTC 42253^T, respectively. The major respiratory quinone of strain BM_7^T was MK-7. The polar lipids were detected as phosphatidylethanolamine, three unidentified phospholipids and four unidentified aminolipids. The dominant fatty acids consisted of iso-C_15 : 0, anteiso-C_15 : 0, C_15 : 1  ω6c, iso-C_17 : 0 3-OH, C_17 : 1  ω6c, C_17 : 0 3-OH and C_17 : 0. The genome size of strain BM_7^T is 5.6 Mb, with G+C content of 43.4 mol%. Based on the phylogenetic and phenotypic characteristics, strain BM_7^T was considered to represent a novel species of the genus Mangrovibacterium, and the name Mangrovibacterium lignilyticum sp. nov. is proposed. The type strain is BM_7^T (=MCCC 1A15882^T=KCTC 72696^T).

Description of Maribellus sediminis sp. nov., a marine nitrogen-fixing bacterium isolated from sediment of cordgrass and mangrove

Two marine bacterial strains designated Y2-1-60^T and GM1-28 were isolated from sediments of cordgrass and mangrove along the Luoyang estuary in Quanzhou Bay, China, respectively. Both strains were Gram-staining-negative, straight rod-shaped, non-flagellum, facultatively anaerobic, nitrogen-fixing, and did not contain carotenoid pigment. Catalase activities were found to be weak positive and oxidase activities negative. The 16S rRNA gene sequences of the two strains were identical and had maximum similarity of 98.0% with Maribellus luteus XSD2^T, and of <94.5% with other species. ANI value (96.9%) and DDH estimate (71.5%) between the two strains supported that they belonged to the same species. ANI value and DDH estimate between the two strains and M. luteus XSD2^T was 74.3% and 19.4%, respectively, indicating that they represent a novel species. Phylogenetic analysis based on 16S rRNA gene and phylogenomic analysis indicated that strains Y2-1-60^T and GM1-28 formed a monophyletic branch within the genus Maribellus. The respiratory quinone was menaquinone MK-7. The major fatty acid (>10%) consisted of iso-C_15:0, and iso-C_17:0 3-OH. The polar lipids consisted of phosphatidylethanolamine and several unidentified lipids. The genomic G+C contents were 41.9-42.0mol%. Gene annotation revealed that strains Y2-1-60^T and GM1-28 contained a set of nif gene cluster (nifHDKENB) responsible for nitrogen fixation. Based on the above characteristics, strains Y2-1-60^T and GM1-28 represent a novel species within the genus Maribellus. Thus, Maribellus sediminis sp. nov. is proposed with type strain Y2-1-60^T (=MCCC 1K04285^T=KCTC 72884^T), isolated from cordgrass sediment and strain GM1-28 (=MCCC 1K04384=KCTC 72880), isolated from mangrove sediment.

Puteibacter caeruleilacunae gen. nov., sp. nov., a facultatively anaerobic bacterium isolated from Yongle Blue Hole in the South China Sea

Blue holes are unique geomorphological units characterized by steep redox and biogeochemical gradients. Yongle Blue Hole is located on the largest atoll (Yongle Atoll) of the western Xisha Islands in the South China Sea. A Gram-stain-negative, facultatively anaerobic, non-motile, non-flagellated marine bacterium with creamy white colonies, designated JC036T, was isolated from Yongle Blue Hole. Cells were short-rod-shaped and catalase-negative. 16S rRNA gene sequence analysis showed that sequence similarities were lower than 91.6 % against all validly named species in the familyProlixibacteraceae; a reconstructed phylogenetic tree indicated that strain JC036Tformed a lineage with strains in the familyProlixibacteraceae. Growth occurred at 4–37 °C (optimum, 28 °C), at pH 5.0–9.0 (optimum, 7.0) and in the presence of 2–6 % (w/v) NaCl (optimum, 3 %). The prevalent isoprenoid quinone of strain JC036Twas menaquinone-7 (MK-7). Iso-C15 : 0and iso-C17 : 03-OH were the predominant fatty acids. The major polar lipids included a phospholipid, phosphatidylethanolamine, an aminophospholipid and four unidentified lipids. The genomic DNA G+C content of strain JC036Twas 37.8 mol%. Based on physiological and biochemical characteristics and whole genome comparisons, we propose a new genus and species,Puteibacter caeruleilacunaegen. nov., sp. nov., within the familyProlixibacteraceae. The type strain ofPuteibacter caeruleilacunaeis JC036T(=JCM 33128T=MCCC 1K03579T). From this study, a deeper understanding of the community of the microorganism and their roles in biogeochemical cycles, especially anaerobic bacteria, is provided.