Biostimulation of Indigenous Microbes for Uranium Bioremediation in Former U Mine Water: Multidisciplinary approach assessment.

Abstract

Characterising physicochemistry and microbial diversity in uranium (U) mine water is a key prerequisite for understanding the biogeochemical processes occurring in these water mass and for the design of an efficient bioremediation strategy. In this study water samples from two former U-mines in East Germany were analysed. The U and sulphate (SO42−) concentrations of Schlema-Alberoda mine water (U: 1 mg/L; SO42−: 335 mg/L) are 2 and 3 order of magnitude higher than those of the Pöhla sample (U: 0.01 mg/L; SO42−: 0.5 mg/L). U, SO42− and Fe seem to shape the differential microbial diversity of the two water samples. Microbial diversity analysis identified U(VI)-reducing bacteria (e.g., Desulfurivibrio) and wood-degrading fungi (e.g., Cadophora) providing electron donors for the growth of U-reducers. U-bioreduction experiments were performed to screen electron donors (glycerol, vanillic acid and gluconic acid) for Schlema-Alberoda U mine water bioremediation. Glycerol effectively removed 99% of soluble U (initially present as Ca2UO2(CO3)3(aq) and UO2(CO3)34−), along with 95% of Fe and 58% of SO42− from the mine water. The results may contribute to the design of low U concentrations bioremediation strategies based on the biostimulation of U-reducing bacteria.