Aestuariibacter salexigens gen. nov., sp. nov. and Aestuariibacter halophilus sp. nov., isolated from tidal flat sediment, and emended description of Alteromonas macleodii

Abstract

Two strictly aerobic, halophilic strains of the gamma-Proteobacteria, designated JC2042(T) and JC2043(T) were obtained from a sediment sample of getbol, the Korean tidal flat. Comparative 16S rDNA sequence studies revealed that the test strains were related most closely to the type strains of the genera Alteromonas (93.5-95.5%) and Glaciecola (91.1-93.3%). Phylogenetic analyses demonstrated that strains JC2042(T) and JC2043(T) formed a distinct monophyletic clade within the family Alteromonadaceae and clustered distantly with the genera Alteromonas and Glaciecola. Physiological, biochemical and chemotaxonomic data also indicated that the two getbol isolates were significantly different from members of these two genera and others with validly published names. Cells were rod-shaped and motile with a polar flagellum. The major isoprenoid quinone was Q8. The predominant cellular fatty acids were C-16:0, C(18:1)omega7c and a mixture of C(16:1)omega7c and iso-C-15:0 2-OH. DNA G + C contents were 48-54 mol%. On the basis of this polyphasic study, Aestuariibacter gen. nov. is proposed with two novel species, Aestuariibacter salexigens sp. nov. (type strain, JC2042(T) = IMSNU 14006(T) = KCTC 12042(T) = DSM 15300(T)) and Aestuariibacter halophilus sp. nov. (type strain, JC2043(T) = IMSNU 14007(T) = KCTC 12043(T) = DSM 15266(T)). Aestuariibacter salexigens is the type species of the genus. In addition, an emended description of Alteromonas macleodii is proposed.