Halovenus rubra sp. nov., isolated from salted brown alga Laminaria

Halophilic archaeal strain R28(T) was isolated from the brown alga Laminaria produced at Dalian, Liaoning Province, China. The cells of the strain were pleomorphic and lysed in distilled water, stained Gram-negative, and formed red-pigmented colonies. Strain R28(T) was able to grow at 25-50 °C (optimum 42 °C), in the presence of 3.1-5.1 M NaCl (optimum 3.9 M NaCl), with 0.005-1.0 M MgCl(2) (optimum 0.01 M MgCl(2)) and at pH 6.0-9.5 (optimum pH 7.0-7.5). The minimal NaCl concentration to prevent cell lysis was 15 % (w/v). The major polar lipids of the strain were identified as phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, and two glycolipids chromatographically identical to those of Halovenus aranensis CGMCC 1.11001(T). The 16S rRNA gene and rpoB' gene of strain R28(T) were phylogenetically related to the corresponding genes of Hvn. aranensis CGMCC 1.11001(T) (91.9-97.2 and 82.9 % nucleotide identity, respectively). The DNA G+C content of strain R28(T) was determined to be 56.3 mol%. The phenotypic, chemotaxonomic, and phylogenetic properties suggest that strain R28(T) (=CGMCC 1.10592(T) = JCM 17269(T)) represents a novel species of the genus Halovenus, for which the name Halovenus rubra sp. nov. is proposed.