Haloarchaeobius iranensis gen. nov., sp. nov., an extremely halophilic archaeon isolated from a saline lake

Abstract

Strain EB21T was isolated from a brine sample from Aran-Bidgol salt lake, a saline playa in Iran. Strain EB21T was an orange–red-pigmented, motile rod and required at least 2 M NaCl but not MgCl2 for growth. Optimal growth was achieved at 3.5 M NaCl and 0.2 M MgCl2. The optimum pH and temperature for growth were pH 7.5 and 40 °C, while it was able to grow at pH 6.0–8.0 and 25–55 °C. Analysis of the 16S rRNA gene sequence revealed that strain EB21T is a member of the family Halobacteriaceae, showing low levels of similarity to other members of the family. The highest sequence similarities, 91.8, 91.7 and 91.5 %, were obtained with the 16S rRNA gene sequences of the type strains of Halobiforma lacisalsi, Haloterrigena thermotolerans and Halalkalicoccus tibetensis, respectively. Polar lipid analyses revealed that strain EB21T contains phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and phosphatidylglycerol sulfate. Three unidentified glycolipids and one minor phospholipid were also observed. The only quinone present was MK-8(II-H2). The G+C content of its DNA was 67.7 mol%. On the basis of the data obtained, the new isolate could not be classified in any recognized genus. Strain EB21T is thus considered to represent a novel species in a new genus within the family Halobacteriaceae, order Halobacteriales, for which the name Haloarchaeobius iranensis gen. nov., sp. nov. is proposed. The type strain of Haloarchaeobius iranensis is EB21T ( = IBRC-M 10013T = KCTC 4048T).