"SCREENINIG OF SOME MICROBIAL STRAINS CAPABLE OF REMOVING URANIUM FROM POLLUTED AREA S

Abstract

In the present work, two bacterial isolates namely B. pantothenticus, and B. megaterium, previously isolated from the environmental air surrounding the gamma irradiation industrial facility of the National Center for Radiation Research and Technology (NCRRT) have been chosen to evaluate their sorption capacity of uranium from solutions. These bacterial isolates were characterized by their high lipids and phospholipids contents. Besides, reference species designated as P. putida and P. chlororaphis were used for companson. First, the toxic effect of uranium on the growth of these bacterial species was studied at different uranium concentrations (50-400)ppm. The results have indicated that P. chlororaphis was the most resistant species, it was survived uranium concentrations up to 400ppm, while P. putida, B. pantothenticus, and B. megaterium were died at concentrations lower than 400ppm uranium. The ability of these species to adsorb uranium as (uranyl nitrate hexahydrate) was examined at different uranium concentrations (10-300)ppm. The results have shown that the local isolates were more efficient than the reference species, removing larger amount of uranium especially at high uranium concentrations. Moreover, the different factors which may affect the biosorption process including, uranium concentration, cell concentration, physiological state of the cells (living, heat­ killed or gamma radiation-killed), pH, temperature and metabolic inhibitors were also studied.