Salinivibrio proteolyticus sp. nov., a moderately halophilic and proteolytic species from a hypersaline lake in Iran

A novel moderately halophilic, Gram-negative, curved-rod-shaped bacterium, designated strain AF-2004T, was isolated from Bakhtegan Lake, a hypersaline lake with 17 % (w/v) total salt located in the southern region of Iran. Strain AF-2004T was a facultative anaerobe, motile by one polar flagellum, non-sporulating and oxidase- and catalase-positive. It grew at salinities of 1-17 % (w/v) NaCl, showing optimal growth at 5 % (w/v). Growth occurred at 10.0-45.0 degrees C and pH 5.0-9.5, with optimum growth at 32.0-35.0 degrees C and pH 8.0-8.5. Phylogenetic analyses based on 16S rRNA gene sequence comparisons indicated that strain AF-2004T is a member of the genus Salinivibrio. Strain AF-2004T had C18 : 1omega7c (31.6 %), C16 : 1omega7c (22.1 %) and C16 : 0 (20.7 %) as the predominant fatty acids and Q-8 as the major respiratory lipoquinone. The DNA G+C content was 49.5 mol%, which is in the range of values for members of the genus Salinivibrio. On the basis of differentiation from Salinivibrio costicola by phenotypic and chemotaxonomic characteristics, 16S rRNA sequence analysis and DNA-DNA relatedness, it is proposed that strain AF-2004T (=DSM 19052T =CIP 109598T) should be placed in the genus Salinivibrio as the type strain of a novel species, Salinivibrio proteolyticus sp. nov.