Zhu Ting, Zeng Qian, Zhao Changsong, Wen Yufeng, Li Shangqing, Li Feize, Lan Tu, Yang Yuanyou, Liu Ning, Sun Qun, Liao Jiali
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 Bio-resources & Eco-environment of the Ministry of Education, College of Life Sciences, 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.
J Environ Radioact. 2023 May;261:107126. doi: 10.1016/j.jenvrad.2023.107126. Epub 2023 Feb 18.
Uranium biomineralization can slow uranium migration in the environment and thus prevent it from further contaminating the surroundings. Investigations into the uranium species, pH, inorganic phosphate (Pi) concentration, and microbial viability during biomineralization by microorganisms are crucial for understanding the mineralization mechanism. In this study, Bacillus thuringiensis X-27 was isolated from soil contaminated with uranium and was used to investigate the formation process of uranium biominerals induced by X-27. The results showed that as biomineralization proceeded, amorphous uranium-containing deposits were generated and transformed into crystalline minerals outside cells, increasing the overall concentration of uramphite. This is a cumulative rather than abrupt process. Notably, B. thuringiensis X-27 precipitated uranium outside the cell surface within 0.5 h, while the release of Pi into the extracellular environment and the change of pH to alkalescence further promoted the formation of uramphite. In addition, cell viability determination showed that the U(VI) biomineralization induced by B. thuringiensis X-27 was instrumental in alleviating the toxicity of U(VI) to cells. This work offers insight into the mechanism of U(VI) phosphate biomineralization and is a reference for bioremediation-related studies.
铀生物矿化能够减缓环境中铀的迁移，从而防止其进一步污染周围环境。研究微生物进行生物矿化过程中的铀物种、pH值、无机磷酸盐（Pi）浓度以及微生物活力，对于理解矿化机制至关重要。在本研究中，从受铀污染的土壤中分离出苏云金芽孢杆菌X-27，并用于研究由X-27诱导的铀生物矿物的形成过程。结果表明，随着生物矿化的进行，无定形含铀沉积物生成并在细胞外转化为结晶矿物，增加了板菱铀矿的总体浓度。这是一个累积而非突然的过程。值得注意的是，苏云金芽孢杆菌X-27在0.5小时内就在细胞表面外沉淀出铀，而Pi释放到细胞外环境以及pH值变为碱性进一步促进了板菱铀矿的形成。此外，细胞活力测定表明，苏云金芽孢杆菌X-27诱导的U(VI)生物矿化有助于减轻U(VI)对细胞的毒性。这项工作为U(VI)磷酸盐生物矿化机制提供了见解，是生物修复相关研究的参考。
