RESUMEN
A novel extremely halophilic archaeon, designated SAH-A6T, was isolated from a sample of commercial rock salt in Ethiopia. Cells of SAH-A6T were aerobic and pleomorphic. The strain was able to grow at concentrations of 15-30â% (w/v) NaCl (optimum 20-25â% NaCl), at pH 6.0-9.0 (optimum pH 7.0) and in a temperature range of 30-55 °C (optimum 37-45 °C). Mg2+ was not required for growth of SAH-A6T cells. On the basis of 16S rRNA gene sequence analysis, strain SAH-A6T was closely related to Halorubrum halodurans Cb34T (99.1â%), Halorubrum rubrum YC87T (98.9â%), Halorubrum aquaticum EN-2T (98.7â%), Halorubrum cibi JCM 15757T (98.4â%), Halorubrum luteum CGSA15T (97.3â%), Halorubrum lipolyticum 9-3T (97.1â%), Halorubrum tibetense 8W8T (97.1â%), Halorubrum kocurii JCM 1478T (97.1â%), Halorubrum halophilum B8T (97.0â%) and Halorubrum persicum C49T (97.0â%). Phylogenetic analysis based on the rpoB' gene sequences showed that strain SAH-A6T was closely related to Hrr. halodurans Cb34T (99.7â%), Hrr. aquaticum JCM 14031T (99.3â%) and other members of the genus Halorubrum (<99.0â%). The DNA G+C content of the strain was 68.0 mol%. DNA-DNA hybridization between strain SAH-A6T and the most closely related members of the genus Halorubrum were below 55â%, suggesting that the new isolate constitutes a different genospecies. On the bases of chemotaxonomic, phenotypic and genotypic data, strain SAH-A6T (=KCCM 43215T=JCM 31519T) represents a novel species of the genus Halorubrum, for which the name Halorubrumaethiopicum sp. nov. is proposed.