Investigation of ultraviolet radiation resistance bacteria indigenous to south of Iran isolated from near-water soils

Background and Aim : Areas with high ultraviolet radiation which are known as extreme environments are harmful for living organisms. Although there are variety of microorganisms existing in these environments and they are adapted to chemical and physical stresses such as UVB radiation. UVB resistant microorganisms are great source of beneficial metabolites which may be used to improve skin drugs and skincare products. Also, they can be used as anticancer and antioxidants.Methods : Eighty-two pure colonies with different shapes and colors were isolated from seven samples of soil which were collected from the Hormoz island, Qeshm island and Bandar Abbas city which are in south of Iran and they have high levels of solar radiations. To study UVB resistant bacteria soil samples were cultured on Luria Bertani Agar and Tryptone Soy Agar medium and colonies were exposure to UVB lamp (Phillips/۲۰w/۳۱۲nm) in distance of thirty centimeters. After UVB treatment to prevent photoreactivation they wrapped in foils and incubated at ۳۰◦ C. Also, photo reactivation was tested by incubating UVB irradiated colonies under photo-active radiation lamps at ۳۰◦ C.Results : There were four bacteria that they showed high resistance to UVB radiation which include a rod shaped, gram positive, spore forming, catalase and oxidase positive and nonmotile bacterium with pink pigmentation and a coccoid gram positive, catalase positive, oxidase negative and nonmotile bacterium with pink pigmentation which are isolated from Hormoz island’s red soil samples, a coccoid, gram positive, catalase and oxidase positive and motile bacterium with orange pigmentation which was isolated from soil sample of Qeshm island, a coccoid, gram positive, catalase positive, oxidase negative and nonmotile bacterium with pink pigmentation that was isolated from Bandar Abbas’s soil sample. They were able to tolerate ۸۰, ۶۰, ۵۰ and ۶۰ minutes of UVB radiation respectively.Conclusion : UVB resistant bacteria were isolated from the Hormoz island, Qeshm island and Bandar Abbas city which are in south of Iran. These bacteria may have secondary metabolites that have anticancer and antioxidant properties.

کلیدواژه ها:

ultra violet ، antioxidant ، UVB resistant bacteria