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

Abstract

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).