Haloprofundus halophilus sp. nov., isolated from the saline soil of Tarim Basin

Abstract

A novel halophilic archaeon, designated NK23T, was isolated from an inland saline soil sampled from Xinjiang, China. The cells of strain NK23T were observed to be pleomorphic, to stain Gram-negative and form red-pigmented colonies on agar plates. The strain can grow at 25–50 °C (optimum 37 °C), at 0.9–4.8 M NaCl (optimum 2.1 M), at 0–1.0 M MgCl2 (optimum 0.05 M) and at pH 6.5–9.5 (optimum pH 7.0). The polar lipids were found to be phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, mannosyl glucosyl diether, sulfated mannosyl glucosyl diether, and three minor unidentified glycolipids, which were chromatographically identical to those detected in Haloprofundus (Hpf.) marisrubri CGMCC 1.14959T. On the basis of 16S rRNA gene and rpoB′ gene sequence similarities and phylogenetic analysis, strain NK23T was found to be related to Hpf. marisrubri CGMCC 1.14959T (97.8% and 94.1% similarities, respectively). The average nucleotide identity values and in silico DNA–DNA hybridization values between strain NK23T and Hpf. marisrubri SB9T were 85.22% and 29.3%, respectively. The DNA G+C content of the novel strain was determined to be 65.29 mol%. Based on the phenotypic and chemotaxonomic data, together with phylogenetic relationships, strain NK23T (= CGMCC 1.14944T = JCM 30670T) is considered to represent a new species of the genus Haloprofundus, for which the name Haloprofundus halophilus sp. nov. is proposed.