Natronorubrum sulfidifaciens sp. nov., an extremely haloalkaliphilic archaeon isolated from Aiding salt lake in Xin-Jiang, China

An extremely haloalkaliphilic archaeon, strain AD2^T, was isolated from Aiding salt lake in Xin-Jiang China. Strain AD2^T required at least 12% NaCl for growth. MgCl₂ was not required. The isolate was able to grow over a pH range of 8.0-10.0 and temperature range of 20-55°C, with optimal growth at pH 8.7-9.2 and 44-47°C. The major polar lipids of strain AD2^T were phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester; glycolipids were not detected. Analysis of its 16S rRNA gene sequence indicated that strain AD2^T was phylogenetically related to members of the genus Natronorubrum, with sequence similarities to the type strains of Natronorubrum bangense, Natronorubrum tibetense and Natronorubrum aibiense of 97.1, 95.9 and 96.1%, respectively. The G + C content of its DNA was 60.9 mol% (T_m). Levels of DNA-DNA relatedness between strain AD2^T and the type strains of Nrr. bangense, Nrr. tibetense and Nrr. aibiense were 49, 38 and 41%, respectively. It was concluded that strain AD2^T represents a novel species of the genus Natronorubrum, for which the name Natronorubrum sulfiditaciens sp. nov. is proposed. The type strain is AD2^T (=CGMCC 1.6307^T=JCM 14089^T).