Halovenus aranensis gen. nov., sp. nov., an extremely halophilic archaeon from Aran-Bidgol salt lake

Abstract

A novel red-pigmented halophilic archaeon, strain EB27(T), was isolated from Aran-Bidgol salt lake, a hypersaline playa in Iran. Cells of strain EB27(T) were non-motile and pleomorphic (rods to triangular or disc-shaped). Strain EB27(T) required at least 2.5 M NaCl and 0.1 M MgCl(2) for growth. Optimal growth was achieved at 4 M NaCl and 0.5 M MgCl(2). The optimum pH and temperature for growth were pH 7.5 and 40 °C; it was able to grow at pH 6.0-8.0 and 25-50 °C. 16S rRNA gene sequence analysis showed that strain EB27(T) is a member of the family Halobacteriaceae; however, levels of 16S rRNA gene sequence similarity were as low as 90.0, 89.3 and 89.1 % to the most closely related haloarchaeal taxa, namely Halalkalicoccus tibetensis DS12(T), Halosimplex carlsbadense 2-9-1(T) and Halorhabdus utahensis AX-2(T), respectively. The DNA G+C content of strain EB27(T) was 61 mol%. Strain EB27(T) contained phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester, common phospholipids found in haloarchaea, together with two minor phospholipids. The only quinone present was MK-8(II-H(2)). Physiological, biochemical and phylogenetic differences between strain EB27(T) and recognized genera of extremely halophilic archaea suggest that this strain represents a novel species in a new genus within the family Halobacteriaceae, for which the name Halovenus aranensis gen. nov., sp. nov. is proposed. The type strain of Halovenus aranensis, the type species of the new genus, is strain EB27(T) ( = IBRC-M 10015(T) = CGMCC 1.11001(T)).