Natronorubrum aibiense sp. nov., an extremely halophilic archaeon isolated from Aibi salt lake in Xin-Jiang, China, and emended description of the genus Natronorubrum.

An extremely halophilic archaeon (strain 7-3(T)) was isolated from Aibi salt lake in Xin-Jiang, China. It formed small (<1.0 mm), red, elevated colonies on salt-milk agar medium. Strain 7-3(T) was able to grow at pH 6.5-9.5 (optimum pH 8.0) and at 20-50 degrees C (optimum 45 degrees C). Analysis of its 16S rRNA gene sequence indicated that strain 7-3(T) was phylogenetically related to members of the genus Natronorubrum, with sequence similarities of 97.0 % to Natronorubrum bangense A33(T) and 95.2 % to Natronorubrum tibetense GA33(T). The G+C content of its DNA was 61.2 mol% (T(m)). Levels of DNA-DNA relatedness to Nrr. bangense and Nrr. tibetense were 45 and 37 %, respectively. It is concluded that strain 7-3(T) (=CGMCC 1.4299(T)=JCM 13488(T)) should be classified as the type strain of a novel species of the genus Natronorubrum, for which the name Natronorubrum aibiense sp. nov. is proposed. Based on the properties of Nrr. aibiense given here and of those of Nrr. bangense and Nrr. tibetense described previously, an emended description of the genus Natronorubrum is presented.