Isolation and characterization of Halobacterium salinarum from saline lakes in Iran

Introduction and objective: Extremely halophilic Archaea belonging to the order Halobacteriales had been isolated from various hyper saline environments such as the Dead Sea, the Great Salt Lake, Sabkhas Lake, and natural or artificial Salterns. The main aim of this study was to isolate and characterize Halobacterium salinarum strains from samples of saline soils and lake water collected from four distinct regions of Iran.

Materials and methods: Saline soil samples and lake water samples were collected from different zones of Iran including a high salinity lake in Qom and Fars and also Seawater of Oromiea Lake and Persian Gulf. For isolation of H. salinarum from collected samples, Halobacterium salinarum medium were used. Isolates were identified by biochemical tests such as motility and morphological features, then identification confirmed by molecular characterization. Optimum NaCl requirement, pH and temperature were determined.

Results: The obtained results showed two isolates were motile, rod, Gram-negative, oxidase and catalase positive, with red pigmentation which grew in the presence of 25% NaCl. Isolates could hydrolyze casein and gelatin. The result of molecular characterization showed that two strains were H. salinarum. Basic local alignment search tool (BLAST) analysis showed 99% homology between these strains and H. salinarum strain R1.

Conclusion: In this investigation we succeeded to isolate and identify H. salinarum in Iran saline ecosystems. There is a large diversity among halophilic bacteria in Iran ecosystems and isolation of H. salinarum from saline lakes will provide better information about halophilic bacteria in Iran ecosystems.