Halalkalicoccus tibetensis gen. nov., sp. nov., representing a novel genus of haloalkaliphilic archaea.

A haloalkaliphilic archaeon (strain DS12T) isolated from Lake Zabuye, the Tibetan Plateau, China, was characterized to elucidate its taxonomy. The strain was aerobic, chemo-organotrophic, and grew optimally at 40 degrees C, pH 9.5-10.0 and 3.4 M NaCl. Cells of strain DS12T were non-motile cocci and stained Gram-variable. The major polar lipids of strain DS12T were diphytanyl and phytanyl-sesterterpanyl diether derivatives of phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester. No glycolipids were detected. Phylogenetic analysis revealed that the strain formed a distinct lineage within the family Halobacteriaceae. The low 16S rRNA gene sequence similarity values to its closest relatives (91.5-92.5 %) and its signature bases both suggest that the strain has no close affinity with any members of the family Halobacteriaceae with validly published names. Therefore, it is proposed that strain DS12T (=AS 1.3240T=JCM 11890T) represents the type strain of a novel species in a new genus, Halalkalicoccus tibetensis gen. nov., sp. nov.