Bacillus iranensis sp. nov., a moderate halophile from a hypersaline lake

Abstract

A Gram-positive, moderately halophilic rod, designated X5BT, was isolated from saline mud of the hypersaline lake Aran-Bidgol in Iran. Strain X5BT was a strictly aerobic, motile bacterium that produced ellipsoidal endospores at a central-subterminal position in non-swollen sporangia. The isolate grew at pH 7.0-10.0 (optimum pH 7.5), at 25-45 °C (optimum 35 °C) and with 2.5-15 % (w/v) NaCl (optimum 5-7.5 %). On the basis of 16S rRNA gene sequences, strain X5BT belonged to the genus Bacillus and showed highest similarity with Bacillus persepolensis HS136T (95.6 % 16S rRNA gene sequence similarity) and Bacillus salarius BH169T (95.5 %). The DNA G+C content was 42.4 mol%. The major cellular fatty acids were anteiso-C15:0 and iso-C15:0 and the polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, three phospholipids and two glycolipids. The diamino acid found in the cell-wall peptidoglycan was meso-diaminopimelic acid and the isoprenoid quinones were MK-7 (92 %), MK-6 (6 %) and MK-5 (2 %). On the basis of phylogenetic, chemotaxonomic and phenotypic data, a novel species of the genus Bacillus is proposed, with the name Bacillus iranensis sp. nov. The type strain is X5BT (=IBRC 10446T=DSM 23995T).