Molecular identification of ultraviolet-resistant bacteria indigenous to desert areas of Iran

Background and Aim : Hot and drouthy deserts have limitative factors as high temperature, drought, high solar radiation and salinity, but there are various microorganisms which lives in these extreme environments and they are adapted to harmful factors. UVB resistant bacteria can be used in medical and biotechnological industries due to their secondary metabolites which may be used as antioxidants and anticancer, and also, used in skincare products.Methods : Eight soil samples were collected from desert areas in Qazvin and Qom, cities with high levels of radiation in Iran. Soil samples were cultured on Tryptone Soy Agar and Luria Bertani Agar medium and ۱۱۲ colonies, with different shape and color, were isolated. Pure colonies were in exposure to UVB lamp (Philips/۲۰w) with wavelength of ۳۱۲ nm, from ۳۰ centimeters distance for ۲۰ to ۹۰ minutes. Then to avoid photoreactivation they were 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. All of experiments were repeated three times.Results : Finally, four bacteria were highly resistant to UVB radiation which include: ۱. A coccoid, gram positive, catalase and oxidase positive and nonmotile bacterium with yellow pigmentation ۲. A coccoid, gram positive, catalase positive, oxidase negative and nonmotile bacterium with orange pigmentation, ۳. A coccoid, gram positive, catalase positive, oxidase negative and nonmotile bacterium with orange pigmentation, that were isolated from Qazvin’s soil samples, ۴. A rod shaped, gram positive, spore forming, catalase and oxidase positive and nonmotile bacterium which were isolated from Qom’s soil samples and they could tolerate ۵۰, ۶۰, ۵۰ and ۸۰ minutes of UVB radiation, respectively.Conclusion : UVB resistant bacteria were isolated from desert area of Iran. These bacteria may have secondary metabolites that have anticancer and antioxidant properties and can be used as skincare products like sunscreen.

کلیدواژه ها:

ultra violet ، antioxidant ، UVB ، resistant bacteria