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 M39^T and C2-7^T, were isolated from the coastal sediment of Xiaoshi Island, Weihai, PR China. Growth of strain M39^T occurred at 15-37 °C, at pH 6.0-9.0 and in the presence of 1.0-9.0 % (w/v) NaCl. Strain C2-7^T 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 M39^T and C2-7^T belong to the phylum Bacteroidota. Based on the results of 16S rRNA gene sequence analysis, the closest relative of strain M39^T was Robiginitalea marina KCTC 92035^T (95.4 %), and the closest relative of strain C2-7^T was Algoriphagus namhaensis DPG-3^T (97.0 %). The percentage of conserved protein and average nucleotide identity values between strain M39^T and some species of the genus Robiginitalea were 66.9-77.6% and 69.3-71.0 %, respectively, while those between strain C2-7^T 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 M39^T consisted of iso-C_{15 : 1} F, iso-C_{15 : 0} and iso-C_{17 : 0} 3-OH, while those of strain C2-7^T were iso-C_{15 : 0} and C_{16 : 1} ω7c/C_{16 : 1} ω6c. MK-6 was the only respiratory quinone that was compatible with the genus of strain M39^T. The predominant menaquinone of strain C2-7^T was MK-7. The major polar lipids of strain M39^T were phosphatidylethanolamine and glycolipids, and those of strain C2-7^T were phosphatidylethanolamine, one unidentified aminolipid and four unidentified lipids. The DNA G+C contents of strains M39^T and C2-7^T were 46.9 and 40.8 mol%, respectively. Based upon the results presented in this study, strains M39^T and C2-7^T 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 M39^T (=MCCC 1H00498^T=KCTC 92014^T) and C2-7^T (=MCCC 1H00414^T=KCTC 92027^T).

Keywords: 16S rRNA gene; Algoriphagus; Robiginitalea; polyphasic taxonomy.