Isolation and identification of cyanobacteria from Kavir National Park hypersaline soils

Cyanobacteria are a unique group of photoautotrophic bacteria that some of them due to their structural characteristics show a significant tolerance to salinity. These organisms play an important role in terrestrial environments, especially in arid and semi-arid region. In this study, soil cyanobacteria were isolated from the desert regions of Iran and then isolates resistant to hypersaline conditions identified. 40 soil samples were collected from the Kavir National Park. Samples were separated after culture in BG11 and ASN III (3.5, 5, 6 and 7% of NaCl) mediums and incubated under appropriate conditions of temperature and light and identified initially using morphological keys and then by molecular methods. Out of 40 sampling sites cyanobacteria were isolated only from four hypersaline sites. Twenty-seven morphotypes were identified in medium without sodium chloride that five strains belonging to two genera were able to grow in the presence of 3.5% sodium chloride. Among the five strains, three strains in 5% and two strains in 6% of sodium chloride grew. Only Phormidium autumnale 61et was able to tolerate 7% sodium chloride that was isolated from the site with 87.80 dS/m. The results showed that some isolated cyanobacteria from soils of Kavir National Park can grow in extreme conditions such as salinity stress and create a biologically active mass.