Halogranum gelatinilyticum sp. nov. and Halogranum amylolyticum sp. nov., isolated from a marine solar saltern, and emended description of the genus Halogranum

Abstract

Two extremely halophilic archaeal strains, designated TNN44Tand TNN58T, were isolated from Tainan marine solar saltern near Lianyungang city, Jiangsu province, China. Cells of the two strains were pleomorphic and Gram-stain-negative; colonies were red-pigmented. Strains TNN44Tand TNN58Twere able to grow at 20–50 °C (optimum 37 °C for both), in the presence of 1.4–5.1 M NaCl (optimum 3.4–3.9 M NaCl) and at pH 5.5–9.0 (optimum pH 6.5–7.0); neither strain required Mg2+for growth. Cells lysed in distilled water. On the basis of 16S rRNA gene sequence analysis, strains TNN44Tand TNN58Twere related closely toHalogranum rubrumRO2-11T(96.2 and 97.2 % similarity, respectively). The polar lipids of the two strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate (trace), and one major glycolipid and one minor glycolipid chromatographically identical to sulfated mannosyl glucosyl diether and mannosyl glucosyl diether, respectively; other trace unidentified lipids were also detected. The DNA G+C content of strains TNN44Tand TNN58Twas 64.0 and 62.0 mol%, respectively. The level of DNA–DNA relatedness between strains TNN44Tand TNN58Twas 37.2 %, and these two strains showed a low level of DNA–DNA relatedness withHalogranum rubrumRO2-11T(40.6 and 44.4 %, respectively). Two novel species of the genusHalogranumare proposed to accommodate these two strains,Halogranum gelatinilyticumsp. nov. (type strain TNN44T = CGMCC 1.10119T = JCM 16426T) andHalogranum amylolyticumsp. nov. (type strain TNN58T = CGMCC 1.10121T = JCM 16428T).