Halomicroarcula limicola sp nov., isolated from a marine solar saltern, and emended description of the genus Halomicroarcula

Halophilic archaeal strain YGHS32(T) was isolated from the Yinggehai marine solar saltern near Shanya city of Hainan Province, China. Cells of the strain were pleomorphic and lysed in distilled water, stained Gram-negative and formed red-pigmented colonies. Strain YGHS32(T) was able to grow at 20-50 degrees C (optimum 37 degrees C), in the presence of 0.9-4.8 M NaCl (optimum 2.1 M NaCl), with 0.005-1.0 M MgCl2 (optimum 0.3 M MgCl2) and at pH 6.0-8.5 (optimum pH 7.5). The minimal NaCl concentration to prevent cell lysis was 5% (w/v). The major polar lipids of the strain were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and four major glycolipids chromatographically identical to sulfated mannosyl glucosyl diether, mannosyl glucosyl diether, glucosyl mannosyl glucosyl diether and a diglycosyl diether. Strain YGHS32(T) had two dissimilar 16S rRNA genes and both of them were phylogenetically related to those of Halomicroarcula pellucida JCM 17820(T) (92.9-96.3% sequence similarity). The rpoB' gene sequence similarity between strain YGHS32T and Halomicroarcula pellucida JCM 17820(T) was 91.3%. The DNA G+C content of strain YGHS32(T) was 64.0 mol%. The DNA-DNA hybridization value between strain YGHS32(T) and Halomicroarcula pellucida JCM 17820(T) was 45%. It was concluded that strain YGHS32(T) (=CGMCC 1.12129(T)=JCM 18640(T)) represents a novel species of the genus Halomicroarcula, for which the name Halomicroarcula limicola sp. nov. is proposed. An emended description of the genus Halomicroarcula is also presented.