In the present study, uranium absorption capacity of Bacillus pantothenticus and Bacillus megaterium, previously isolated from the environmental air surrounding the 60Co gamma source, is reported. Pseudomonas putida and Pseudomonas chlororaphis were used as reference species. Concerning uranium uptake, the local species were more efficient than the reference ones. The maximum uptake was achieved by B. megaterium and B. pantothenticus at 20 microgram U mL-1 and by B. pantothenticus at 30 microgram U mL-1. The transmission electron microscope examination indicated that uranium was absorbed onto the cell surface of the studied isolates. Furthermore, the increase in biomass concentration has shown an increase in the total amount of uranium removed. Dead cells exhibited uranium uptake to the same or greater extent than living cells. B. pantothenticus, P. putida, and P. chlororaphis achieved maximum uptake at pH 4.0, whereas B. megaterium it was pH 6.0. Temperature had an important role in uranium absorption of all the studied species except B. pantothenticus,. Metabolic inhibitors did not affect the uptake.U radu je proučavan kapacitet apsorpcije urana bakterija Bacillus pantothenticus i Bacillus megaterium izoliranih iz zraka izloženog izvoru gama-zračenja iz 60Co. Te bakterije su se pokazale učinkovitije u usporedbi s referentnim vrstama Pseudomonas putida i Pseudomonas chlororaphis. Maksimalna postignuta koncentracija bila je 10, 20, odnosno 30 µgU mL-1. Nadalje, povećanje koncentracije u biomasi pratilo je povećanje ukupne količine uklonjenog urana. Mrtve stanice su apsorbirale uran u istoj ili većoj mjeri nego žive stanice. Maksimum apsorpcije B. pantothenticus, P. putida i P. chlororaphis postignut je pri pH 4,0, a B. megaterium pri pH 6,0. Kod svih ispitivanih vrsta osim B. pantothenticus, temperatura je značajno utjecala na apsorpciju dok inhibitori metaboličkih reakcija nisu utjecali. Pretraživanje transmisijskim elektronskim mikroskopom ukazalo je da se uran apsorbirao na površinu stanice
