Isolation and identification of cobalt- and caesium-resistant bacteria from a nuclear fuel storage pond.

One of the issues facing the nuclear power industry is how to store spent nuclear fuel which is contaminated with radionuclides produced during nuclear fission, including caesium ((134)Cs(+), (135)Cs(+) and (137)Cs(+)) and cobalt ((60)Co(2+)). In this study, we have isolated Co(2+)- and Cs(+)-resistant bacteria from water collected from a nuclear fuel storage pond. The most resistant Cs(+) and Co(2+) isolates grew in the presence of 500 mM CsCl and 3 mM CoCl2. Strain Cs67-2 is resistant to fourfold more Cs(+) than Cupriavidus metallidurans str. CH34 making it the most Cs(+)-resistant strain identified to date. The Cs(+)-resistant isolates were closely related to bacteria in the Serratia and Yersinia genera, while the Co(2+)-resistant isolates were closely related to the Curvibacter and Tardiphaga genera. These new isolates could be used for bioremediation.