Anaerobic Reduction of U(Vi) by Bacillius Sp. X02 and its Electron Transfer Mechanism

To explore the electron transfer mechanism of U(VI) reduction by microorganisms under anaerobic conditions, this study conducted experiments on the facultative anaerobic bacterium Bacillus sp. X02 for anaerobic reduction of U(VI). The results showed that the reduction rate of U(VI) by Bacillus sp. X02 was 62.43%. While the addition of the electron transfer inhibitor NaN3 reduced the reduction rate of U(VI) for 25.37%. Raman spectroscopy, electrochemical experiments and iTRAQ results showed that the cytochrome c and oxidative phosphorylation signaling pathway was involved in the anaerobic reduction of U(VI) by Bacillus sp. X02. Specifically, with glucose as the electron donor, NADH is generated by glycolysis, oxidized by complex I (or complex II) to generate electrons, which were transferred to complex III via ubiquinone (coenzyme-Q), and then by cytochrome c-mediated transfer to complex IV, and finally to the solution, where U(VI) gets an electron reduction to U(V) and then to U(IV).