Algibacter agarivorans sp. nov. and Algibacter agarilyticus sp. nov., isolated from seawater, reclassification of Marinivirga aestuarii as Algibacter aestuarii comb. nov. and emended description of the genus Algibacter.

Two yellow-pigmented, rod-shaped, non-motile, Gram-reaction-negative and aerobic bacterial strains, designated KYW560(T) and KYW563(T), were isolated from seawater collected from Gwangyang Bay, Republic of Korea. The isolates required sea salts for growth. Flexirubin-type pigments were absent. The common major cellular fatty acids (>5% of total) of the two strains were C(16:0), C(18:0), iso-C(15:0), anteiso-C(15:0), iso-C(15:1) G, iso-C(17:0) 3-OH and summed feature 3 (C(16:1)ω6c and/or C(16:1)ω7c). Strain KYW560(T) also contained iso-C(15:0) 3-OH and C(20:1)ω9c as major fatty acids. The main polar lipids were phosphatidylethanolamine, an unidentified aminolipid and two unidentified lipids. The predominant isoprenoid quinone was MK-6. The DNA G+C contents of strains KYW560(T) and KYW563(T) were 41.0 ± 0.7 and 38.3 ± 0.4 mol% (mean ± sd of three determinations), respectively. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolates belonged to the family Flavobacteriaceae, and were related to the genus Algibacter. Based on data from this taxonomic study using a polyphasic approach, it is proposed that the isolates represent novel species of the genus Algibacter, for which the names Algibacter agarivorans sp. nov. (type strain, KYW560(T) =KCTC 23855(T) =JCM 18285(T)) and Algibacter agarilyticus sp. nov. (type strain, KYW563(T) =KCTC 23857(T) =JCM 18275(T)) are proposed. Reclassification of Marinivirga aestuarii as Algibacter aestuarii comb. nov. and emended description of the genus Algibacter are also proposed.