Bioeduction of U(VI) in the presence of citrate, NTA, and EDTA

Suzuki, Yoshinori; Tanaka, Kazuya  ; Kozai, Naofumi   ; Onuki, Toshihiko

Reduction of U(VI) by Shewanella putrefaciens in the presence of citrate, NTA, and EDTA was examined to elucidate effects of strong complexation agents on the biological reduction. In the control media containing no citrate, NTA, and EDTA, the concentration of dissolved U decreased with time and precipitates were observed. In the presence of citrate, NTA, or EDTA, the reduced species of U(IV) were soluble U(IV)-organic complexes. The initial reduction rate of U(VI) in the citrate media was much slower than those in the NTA and EDTA media. These results indicate that the presence of strong complexation agents affect the chemical species of U(IV) and the reduction rate of U(VI).