Engineering of Deinococcus radiodurans R1 for bioprecipitation of uranium from dilute nuclear waste

Abstract

Genetic engineering of radiation-resistant organisms to recover radionuclides/heavy metals from radioactive wastes is an attractive proposition. We have constructed a Deinococcus radiodurans strain harboring phoN, a gene encoding a nonspecific acid phosphatase, obtained from a local isolate of Salmonella enterica serovar Typhi. The recombinant strain expressed an ~27-kDa active PhoN protein and efficiently precipitated over 90% of the uranium from a 0.8 mM uranyl nitrate solution in 6 h. The engineered strain retained uranium bioprecipitation ability even after exposure to 6 kGy of ⁶⁰Co gamma rays. The PhoN-expressing D. radiodurans offers an effective and eco-friendly in situ approach to biorecovery of uranium from dilute nuclear waste.