Thalassobacillus Cyri sp. nov., a Moderately Halophilic Gram-positive Bacterium from a Hypersaline Lake

A Gram-positive, moderately halophilic bacterium, designated strain HS286T, was isolated from water of the hypersaline Lake Howz-Soltan in Iran. Cells were strictly aerobic, rod-shaped, motile and able to produce ellipsoidal endospores at a central-subterminal position in swollen sporangia. Isolate HS286T grew in a complex medium supplemented with 1-15% (w/v) NaCl, with optimum growth at 8.0% (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that strain HS286T was closely related to Thalassobacillus devorans G-19.1T (99.4% gene sequence similarity). The other closest species were Halobacillus yeomjeoni MSS-402T (96.9 %) and other species of the genus Halobacillus (with 96.7-93.5% similarity). Strain HS286T had cell-wall peptidoglycan based on meso-diaminopimelic acid and MK-7 as the respiratory isoprenoid quinone. The major fatty acids were anteiso-C15:0 (43.8 %), iso-C16:0 (21.4 %), iso-C14:0 (9.4%), anteiso-C17:0 (8.7%) and iso-C15:0 (7.0%) and the polar lipid pattern consisted of diphosphatidylglycerol, phosphatidylglycerol, two phospholipids and a glycolipid. The DNA G+C content was 43.0 mol%. All of these features confirmed the placement of isolate HS286T within the genus Thalassobacillus. However DNA-DNA hybridization between strain HS286T and the only recognized species of the genus Thalassobacillus, T. devorans G-19.1T, was 27.3%, showing unequivocally that the novel isolate constituted a new genospecies. Strain HS286T could be clearly differentiated from T. devorans and other phylogenetic neighbours on the basis of several phenotypic, genotypic and chemotaxonomic features. Therefore, strain HS286T constitutes a novel species, for which the name Thalassobacillus cyri sp. nov. is proposed. The type strain is HS286T (=CCM 7597T=JCM 15722T).

Iranian Environment Department 3/42274

Ministerio de Educación y Ciencia BIO2006-06927

Junta de Andalucía P06-CVI-01829