US EPA

5075735 

Journal Article 

Co-expression of YieF and PhoN in Deinococcus radiodurans R1 improves uranium bioprecipitation by reducing chromium interference 

Xu, R; Wu, K; Han, H; Ling, Z; Chen, Z; Liu, P; Xiong, J; Tian, F; Zafar, Y; Malik, K; Li, X 

2018 

Yes 

Chemosphere
ISSN: 0045-6535
EISSN: 1879-1298 

211 

1156-1165 

English 

30223331 

10.1016/j.chemosphere.2018.08.061 

WOS:000446149600126 

Overexpression of the enzyme phosphatase (PhoN/PhoK) in the radiation-resistant bacterium Deinococcus radiodurans could be an efficient strategy for uranium remediation. However, the presence of other metals in nuclear wastes often interferes with uranium bioprecipitation. In our study, the uranium-precipitating ability of the PhoN-expressing D. radiodurans strain (Deino-phoN) significantly decreased by 45.4% in 13 h in the presence of chromium (VI); however, it was partially recovered after supplementation with chromium (III). Therefore, the reduction of chromium (VI) to chromium (III) was obtained by the co-expression of the YieF protein and PhoN in D. radiodurans (Deino-phoN-yieF). As a result, an increase in the chromium (VI) reduction (25.1%) rate was observed in 24 h. Furthermore, uranium precipitation also increased by 28.0%. For the decontamination of groundwater, we immobilized Deino-phoN-yieF cells using Polyvinyl alcohol (PVA)-sodium alginate (SA) beads, followed by incubation in a bioreactor. Approximately 99% of chromium (VI) and uranium (VI) was removed after 4 continuous cycles operated for a period of over 20 days at room temperature (25 °C). Therefore, Deino-phoN-yieF could be used as a potential biological agent for mixed radioactive nuclear waste remediation.