Abstract:A sulfate-reducing bacterial strain, A1SXC21Q, was enriched and isolated from the soil in a uranium mine, and the desulfurization and uranium-fixing properties of the strain and the stability of its uranium-fixing products were investigated under different pH value, temperature, and SO42- condition. The results show that elevated pH favores the removal of SO42- and uranium by the bacterial strain, and the removal of both SO42- and uranium can reach higher than 95% under the initial pH value of 5.5—7.0. Increasing initial SO42- concentration decreases the removal rate of SO42- and uranium, however, the removal rate of SO42- and uranium can still reach 75.42% and 50.57% when the initial SO42- concentration is 2 000 mg/L. The removal of SO42- and uranium can be accelerated significantly by increasing temperature, and the removal rate of both SO42- and uranium reaches about 95% at 25—35 ℃. A1SXC21Q can transfer uranium enriched on its surface to the interior of the cell and form multiple "nucleated" uranyl phosphate complexes, resulting in a stabilized uranium-fixing product. From the perspective of the desulfurization and uranium fixation effect of A1SXC21Q and the stability of its solid uranium fixation products, it is expected that A1SXC21Q can be used in the subsequent experimental research of groundwater bioremediation technology in the retired mining area of acid leaching uranium mines in the future.