Biosorption and biomineralization of U(VI) by Kocuria rosea: Involvement of phosphorus and formation of U–P minerals

The biosorption and biomineralization behavior of U(VI) by Kocuria rosea with uranium resistance higher than other general microorganisms was investigated in this study. The results showed the obvious effects of initial U(VI) concentration, biomass, time, and especially pH, and presented that U(VI) was immobilized to K. rosea by physical and chemical action. The characterization results for the precipitation proved that U-P minerals with U(VI) (H3OUO2PO4·3H2O, H2(UO2)2(PO4)2·8H2O) or U(IV) (CaU(PO4)2) were dominant, and the crystallization level increased with time. In the process, the phosphorous containing groups, amino, hydroxyl and carboxyl groups played important roles in adsorption of U(VI), and the phosphate groups were crucial in immobilization of uranium, showing the importance of groups containing phosphorus in both biosorption and biomineralization processes. Our findings focus on the biosorption and biomineralization mechanism of U(VI) by K. rosea, emphasize the synergy of physical adsorption and chemical immobilization in the process and formation of U(VI)-P and U(IV)-P minerals, and highlight the significance of phosphorus involvement in the reaction.