Haloplanus salinarum sp. nov., an extremely halophilic archaeon isolated from a solar saltern.

An extremely halophilic archaeal strain SP28 was isolated from the Gomso solar saltern, Republic of Korea. Cells of the new strain SP28 were pleomorphic and Gram stain negative, and produced red-pigmented colonies. These grew in medium with 2.5-4.5 M NaCl (optimum 3.1 M) and 0.05-0.5 M MgCl2 (optimum 0.1 M), at 25-50 °C (optimum 37 °C) and at a pH of 6.5-8.5 (optimum pH 8.0). Mg was required for growth. A concentration of at least 2 M NaCl was required to prevent cell lysis. Polar lipids included phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and one glycolipid chromatographically identical to sulfated mannosyl glucosyl diether. 16S rRNA and rpoB' gene sequence analyses showed that strain SP28 is closely related to Haloplanus ruber R35 (97.3 and 94.1 %, 16S rRNA and rpoB' gene sequence similarity, respectively), Haloplanus litoreus GX21 (97.0 and 92.1 %), Haloplanus salinus YGH66 (96.0 and 91.9 %), Haloplanus vescus RO5-8 (95.9 and 90.9 %), Haloplanus aerogenes TBN37 (95.6 and 90.3 %) and Haloplanus natans RE-101 (95.3 and 89.8 %). The DNA G+C content of the novel strain SP28 was 66.2 mol%, which is slightly higher than that of Hpn.litoreus GX21 (65.8 mol%) and Hpn.ruber R35 (66.0 mol%). DNA-DNA hybridization values betweenHpn.ruber R35 and strain SP28 and between Hpn.litoreus GX21 and strain SP28 were about 24.8 and 20.7 %, respectively. We conclude that strain SP28 represents a novel species of the genus Haloplanus and propose the name Haloplanus salinarum sp. nov. The type strain is SP28 (=JCM 31424=KCCM 43210).