Hülya Bayburt, Jeong‐Min Kim, Byeong Jun Choi, Jae Kyeong Lee, Che Ok Jeon
Two Gram-stain-negative, obligately aerobic, non-motile rod-shaped bacteria, designated strains W23 T and W31 T , exhibiting catalase- and oxidase-positive activities, were isolated from the phycosphere of a marine red alga. Strain W23ᵀ grew optimally at 25 °C, pH 8.0–9.0, and 3.0–4.0 % ( w / v ) NaCl, whereas strain W31 T grew optimally at 25–30 °C, pH 8.0, and 3.0–4.0 % NaCl. Ubiquinone-8 was the major respiratory quinone in both strains. Strain W23 T predominantly contained C 16:0 , summed features 3 (C 16:1 ω 7 c and/or C 16:1 ω 6 c ) and 8 (C 18:1 ω 7 c and/or C 18:1 ω 6 c ), and C 12:0 as major fatty acids, with phosphatidylglycerol and phosphatidylethanolamine as main polar lipids. In contrast, strain W31 T exhibited isoC 15:0 , summed feature 1 (isoC 15:1 H and/or C 13:0 3-OH), C 12:0 , and isoC 11:0 , with diphosphatidylglycerol, phosphatidylethanolamine, and phosphatidylmonomethylethanolamine as dominant polar lipids. The genomic DNA G + C contents were 44.5 % for strain W23 T and 42.3 % for strain W31 T . Phylogenetic, genomic, and phenotypic analyses support the classification of strains W23ᵀ and W31ᵀ as novel species within the genera Ningiella and Marinicella , for which the names Ningiella algicola sp. nov. (W23 T = KACC 23126 T = JCM 35964 T ) and Marinicella algicola sp. nov. (W31 T = KACC 23129 T = JCM 35965 T ) are proposed. Genome-based phylogenomic analyses also supported the reclassification of Alteromonas lipolytica , Alteromonas alba , and Alteromonas oceani into the genus Marisediminitalea ; Alteromonas sediminis into a new genus, Paralteromonas ; and Alteromonas flava , Alteromonas facilis , and Alteromonas arenosi into another new genus, Neoalteromonas . Furthermore, Methylophaga aminisulfidivorans is reclassified as a later heterotypic synonym of Methylophaga thalassica .