Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, 610064, PR China.
Key Laboratory of Radiation Physics and Technology of the Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu, 610064, PR China; Key Laboratory of Biological Resource and Ecological Environment of the Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610064, PR China.
Chemosphere. 2022 Jul;298:134196. doi: 10.1016/j.chemosphere.2022.134196. Epub 2022 Mar 8.
The important role of microbes in the biomineralization and migration behavior of uranium in the field of environmental chemistry has been well emphasized in previous work. However, limited work on mineralization processes of indigenous microorganism has prevented us from a deeper understanding of the process and mechanisms of uranium biomineralization. In this work, the dynamic process and mechanism of uranium biomineralization in Enterobacter sp. X57, a novel uranium-tolerant microorganism separated from uranium contaminated soil, were systematically investigated. Enterobacter sp. X57 can induce intracellular mineralization of U (VI) to Uramphite (NHUOPO·3HO) under neutral conditions by alkaline phosphatase. In this biomineralization process, soluble U (VI) first bonded with the amino and phosphate groups on the plasma membrane, providing initial nucleation site for the formation of U (VI) biominerals. Then the impairment of cell barrier function and the enhancement of alkaline phosphatase metabolism occurred with the accumulation of uranium in cells, creating a possible pathway for soluble U (VI) to diffuse into the cell and be further mineralized into U (VI)-phosphate minerals. All the results revealed that the intracellular biomineralization of uranium by Enterobacter sp. X57 was a combined result of biosorption, intracellular accumulation and phosphatase metabolism. These findings may contribute to a better understanding of uranium biomineralization behavior and mechanism of microorganisms, as well as possible in-situ bioremediation strategies for uranium by indigenous microorganisms.
先前的工作已经强调了微生物在环境化学领域中铀的生物矿化和迁移行为中的重要作用。然而，由于对土著微生物矿化过程的研究有限，我们仍无法深入了解铀的生物矿化过程和机制。在这项工作中，我们系统地研究了从铀污染土壤中分离出的新型耐铀微生物 Enterobacter sp. X57 中铀的生物矿化的动态过程和机制。Enterobacter sp. X57 可以通过碱性磷酸酶在中性条件下诱导 U（VI）向 Uramphite（NHUOPO·3HO）的细胞内矿化。在这个生物矿化过程中，可溶性 U（VI）首先与质膜上的氨基和磷酸基团结合，为 U（VI）生物矿的形成提供初始成核位点。然后，随着细胞内铀的积累，细胞屏障功能受损，碱性磷酸酶代谢增强，为可溶性 U（VI）扩散到细胞内并进一步矿化为 U（VI）-磷酸盐矿物创造了可能的途径。所有结果表明，Enterobacter sp. X57 对铀的细胞内生物矿化是生物吸附、细胞内积累和磷酸酶代谢的综合结果。这些发现可能有助于更好地理解微生物对铀的生物矿化行为和机制，以及土著微生物对铀的原位生物修复策略。
