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 γ-Proteobacteria, designated JC2042T and JC2043T, 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 JC2042T and JC2043T 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 C16 : 0, C18 : 1 ω7c and a mixture of C16 : 1 ω7c and iso-C15 : 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, JC2042T=IMSNU 14006T=KCTC 12042T=DSM 15300T) and Aestuariibacter halophilus sp. nov. (type strain, JC2043T=IMSNU 14007T=KCTC 12043T=DSM 15266T). Aestuariibacter salexigens is the type species of the genus. In addition, an emended description of Alteromonas macleodii is proposed.