Aequorivita sediminis sp. nov. and Aequorivita marina sp. nov., isolated from marine sediment.

Two Gram-stain-negative, rod-shaped, non-motile, strictly aerobic strains, forming yellow colonies and designated F6058T and S2608T, were isolated from marine sediment collected in Weihai, PR China. Both strains grow at 4-40 °C (optimum, 30-33 °C), pH 6.0-7.5 (optimum, pH 6.5) and in the presence of 0-7.0 % (w/v) NaCl. The optimum NaCl concentrations for strains F6058T and S2608T were 2.0 % and 2.5 %, respectively. Phylogenetic analysis of the 16S rRNA gene sequences indicated that strains F6058T and S2608T share an evolutionary lineage with members of the genus Aequorivita. The isolates exhibited a 16S rRNA gene sequence similarity of 96.7 % to each other. Strains F6058T exhibited the highest 16S rRNA gene sequence similarity to Aequorivita xiaoshiensis F64183T (98.8 %), and S2608T was most similar to Aequorivita capsosiphonis A71T (96.9 %). Iso-C15:0, anteiso-C15:0 and iso-C17:0 3-OH were the major fatty acids of strains F6058T and S2608T. The sole respiratory quinone of both isolates was menaquinone 6 (MK-6). The polar lipid profiles of the isolates both consisted of phosphatidylethanolamine and phosphoglycolipids; however, strain F6058T exhibited one glycolipid, one aminolipid and two unidentified polar lipids, and strain S2608T also had two glycolipids and one unidentified polar lipid. The DNA G+C contents of strains F6058T and S2608T were 34.6 % and 37.7 mol%, respectively. Based on their phenotypic, chemotaxonomic and genomic characteristics, strains F6058T and S2608T were considered to represent novel species of the genus Aequorivita, for which the names Aequorivita sediminis sp. nov. and Aequorivita marina sp. nov. were proposed. The type strains are F6058T (=KCTC 92653T=MCCC 1H01358T) and S2608T (KCTC 92652T=MCCC 1H01361T).

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

A Gram-stain-negative, facultative anaerobic, motile, rod-shaped and orange bacterium, designated A06T, was obtained off the coast of Weihai, PR China. Cells were 0.4-0.5×0.6-1.0 µm in size. Strain A06T 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 C15:0 2-OH, iso-C15:0, anteiso-C15:0 and iso-C15:1 ω6c. The DNA G+C content of strain A06T 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 A06T is a member of the family Prolixibacteraceae and exhibited the highest sequence similarity to Mangrovibacterium diazotrophicum DSM 27148T (94.3 %). Based on its phylogenetic and phenotypic characteristics, strain A06T 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 A06T (=KCTC 92029T=MCCC 1H00491T). 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 A06T uses an enrichment method, so the isolation of strain A06T is of great significance to the enrichment of marine microbial resources.

Robiginitalea aurantiaca sp. nov. and Algoriphagus sediminis sp. nov., isolated from coastal sediment.

Two novel rod-shaped, Gram-stain-negative, aerobic and non-motile bacterial strains, designated M39T and C2-7T, were isolated from the coastal sediment of Xiaoshi Island, Weihai, PR China. Growth of strain M39T occurred at 15-37 °C, at pH 6.0-9.0 and in the presence of 1.0-9.0 % (w/v) NaCl. Strain C2-7T grew at 15-40 °C, at pH 6.0-8.0 and in the presence of 0.5-8.0 % (w/v) NaCl. Phylogenetic analysis based 16S rRNA gene sequences revealed that strains M39T and C2-7T belong to the phylum Bacteroidota. Based on the results of 16S rRNA gene sequence analysis, the closest relative of strain M39T was Robiginitalea marina KCTC 92035T (95.4 %), and the closest relative of strain C2-7T was Algoriphagus namhaensis DPG-3T (97.0 %). The percentage of conserved protein and average nucleotide identity values between strain M39T and some species of the genus Robiginitalea were 66.9-77.6% and 69.3-71.0 %, respectively, while those between strain C2-7T and some species of the genus Algoriphagus were 68.0-70.1% and 56.1-72.6 %, respectively. The major cellular fatty acids (>10 %) of strain M39T consisted of iso-C15 : 1 F, iso-C15 : 0 and iso-C17 : 0 3-OH, while those of strain C2-7T were iso-C15 : 0 and C16 : 1 ω7c/C16 : 1 ω6c. MK-6 was the only respiratory quinone that was compatible with the genus of strain M39T. The predominant menaquinone of strain C2-7T was MK-7. The major polar lipids of strain M39T were phosphatidylethanolamine and glycolipids, and those of strain C2-7T were phosphatidylethanolamine, one unidentified aminolipid and four unidentified lipids. The DNA G+C contents of strains M39T and C2-7T were 46.9 and 40.8 mol%, respectively. Based upon the results presented in this study, strains M39T and C2-7T represent novel species of the genera Robiginitalea and Algoriphagus, respectively, for which the names Robiginitalea aurantiaca sp. nov. and Algoriphagus sediminis sp. nov. are proposed with the type strains M39T (=MCCC 1H00498T=KCTC 92014T) and C2-7T (=MCCC 1H00414T=KCTC 92027T).

Robiginitalea marina sp. nov., isolated from coastal sediment.

A Gram-stain-negative, orange, aerobic, non-motile, rod-shaped marine bacterium, designated as 2V75T, was isolated from the coastal sediment of Xiaoshi Island, Weihai, China. The strain 2V75T grew at 20-45 °C (optimum, 37 °C), from pH 7.0 to 9.0 (optimum, pH 7.0) and in the presence of 0.5-5% (w/v) NaCl (optimum, 3%). Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain 2V75T was affiliated to the genus Robiginitalea and had the highest sequence similarity with R. biformata KCTC 12146T (93.7%). The ANI values between strain 2V75T and R. biformata KCTC 12146T were 72.6%, respectively. The DNA G + C content was 54.8 mol%. MK-6 was the only respiratory quinone. Based on the phenotypic, phylogenetic and chemotaxonomic data, strain 2V75T should be classified as a novel species in the genus Robiginitalea, for which the name Robiginitalea marina is proposed. The type strain is 2V75T (= KCTC 92035T = MCCC 1H00484T).

Aestuariirhabdus haliotis sp. nov., isolated from abalone viscera and emended description of the genus Aestuariirhabdus.

Two novel strains, Z083T and Z084, were isolated from the viscera of abalone, Haliotis discus hannai, sampled in Weihai, PR China. The phenotypic, chemotaxonomic and genomic characteristics of the two strains were studied. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 99.8 and 98.9 %, respectively, suggesting that the two strains belonged to the same species. The 16S rRNA gene sequence analysis showed 99.8 % similarity between the two strains, while the genome analysis indicated that they were not from one clonal origin. Phylogenetic analysis of 16S rRNA gene sequences showed the two strains belonged to the genus Aestuariirhabdus and Aestuariirhabdus litorea JCM 32043T was the closest strain (97.5 %). Genomic analysis, including calculations of ANI, dDDH, amino acid identity (AAI) and percentage of conserved proteins (POCP), between Z083T, Z084 and A. litorea JCM 32043T clearly separated those two strains from A. litorea JCM 32043T as the values were below the thresholds for species delineation. The genome size of strains Z083T and Z084 were approximately 4.16 and 4.23 Mbp, respectively, and the DNA G+C contents of both strains were 51.8 mol%. According to the phenotypic, chemotaxonomic and phylogenetic characterizations and the results of genome analysis, Z083T and Z084 could be identified as belonging to a novel species of the genus Aestuariirhabdus, for which the name Aestuariirhabdus haliotis sp. nov., is proposed, with Z083T (=MCCC 1H00501T=KCTC 92006T) as the type strain.