Haladaptatus litoreus sp. nov., an extremely halophilic archaeon from a marine solar saltern, and emended description of the genus Haladaptatus

Two extremely halophilic archaea, strains RO1-28^T and RO1-22, were isolated from a marine solar saltern in Jiangsu, China. Both strains required at least 0.05 M Mg²⁺ and 1.7 M NaCl for growth. They were able to grow over a pH range of 6.0-8.5 and a temperature range of 25-55 °C, with optimal pH of 7.0 and optimal temperature of 37-40 °C. Based on 16S rRNA gene sequence analysis, strains RO1-28^T and RO1-22 were closely related to Haladaptatus paucihalophilus, the single species of the genus Haladaptatus, with similarities of 94.0-95.2 %. The major polar lipids of the two strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and three glycolipids chromatographically identical to the glycolipids of Haladaptatus paucihalophilus JCM 13897 ^T. Both strains RO1-28^T and RO1-22 had a DNA G+C content of 54.0 mol% (HPLC). The DNA-DNA hybridization value between the two strains was more than 70% (92 %) and both strains showed low levels of DNA-DNA relatedness (32% and 33 %) with Haladaptatus paucihalophilus JCM 13897^T. It was concluded that strains RO1-28^T and RO1-22 represent a novel species of the genus Haladaptatus, for which the name Haladaptatus litoreus sp. nov. is proposed. The type strain is RO1-28^T (=CGMCC 1.7737^T =JCM 15771^T).