A new uranium bioremediation approach using radio-tolerant Deinococcus radiodurans biofilm

Deinococcus radiodurans is the most radiation-tolerant organism ever known. It has gained importance in recent years as a potential candidate for bioremediation of heavy metals, especially the radioactive type. This study investigates the efficiency of a recombinant D. radiodurans (DR1-bf⁺) strain with an ability to form biofilm for uranium remediation. The modified Arsenazo III dye method was used to estimate the uranium concentration. Uranyl nitrate aqueous solution was generated during the operation of nuclear fuel reprocessing. The D. radiodurans biofilm (DR1-bf⁺) grown in the presence of 20 mM Ca²⁺ showed remarkable ability of uranyl ion removal. DR1-bf⁺ (Ca²⁺) biofilm removed ~75+/-2% of 1000 mg/L uranium within 30 min post-treatment from uranyl nitrate aqueous solution. Uranium removal rate was also found to be directly proportional to biofilm age. This study discusses the ability of D. radiodurans biofilm in uranium removal.