Martínez-Rodríguez Pablo, Sánchez-Castro Iván, Ojeda Jesús J, Abad María M, Descostes Michael, Merroun Mohamed Larbi
Department of Microbiology, University of Granada, Granada, Spain.
Department of Chemical Engineering, Faculty of Science and Engineering, Swansea University, Swansea, United Kingdom.
Front Microbiol. 2023 Jan 9;13:1092184. doi: 10.3389/fmicb.2022.1092184. eCollection 2022.
Industrial activities related with the uranium industry are known to generate hazardous waste which must be managed adequately. Amongst the remediation activities available, eco-friendly strategies based on microbial activity have been investigated in depth in the last decades and biomineralization-based methods, mediated by microbial enzymes (e.g., phosphatase), have been proposed as a promising approach. However, the presence of different forms of phosphates in these environments plays a complicated role which must be thoroughly unraveled to optimize results when applying this remediation process.
In this study, we have looked at the effect of different phosphate sources on the uranium (U) biomineralization process mediated by sp. Be9, a bacterial strain previously isolated from U mill tailings. We applied a multidisciplinary approach (cell surface characterization, phosphatase activity, inorganic phosphate release, cell viability, microscopy, etc.).
It was clear that the U removal ability and related U interaction mechanisms by the strain depend on the type of phosphate substrate. In the absence of exogenous phosphate substrate, the cells interact with U through U phosphate biomineralization with a 98% removal of U within the first 48 h. However, the U solubilization process was the main U interaction mechanism of the cells in the presence of inorganic phosphate, demonstrating the phosphate solubilizing potential of the strain. These findings show the biotechnological use of this strain in the bioremediation of U as a function of phosphate substrate: U biomineralization (in a phosphate free system) and indirectly through the solubilization of orthophosphate from phosphate (P) containing waste products needed for U precipitation.
与铀工业相关的工业活动会产生必须妥善管理的危险废物。在现有的修复活动中，基于微生物活性的生态友好策略在过去几十年中得到了深入研究，并且由微生物酶（如磷酸酶）介导的基于生物矿化的方法已被提出作为一种有前景的方法。然而，这些环境中不同形式磷酸盐的存在起着复杂的作用，在应用这种修复过程时，必须彻底弄清楚这一点以优化结果。
在本研究中，我们研究了不同磷酸盐来源对由菌株Be9介导的铀生物矿化过程的影响，该菌株先前从铀矿尾矿中分离得到。我们采用了多学科方法（细胞表面表征、磷酸酶活性、无机磷酸盐释放、细胞活力、显微镜检查等）。
很明显，该菌株的铀去除能力及相关的铀相互作用机制取决于磷酸盐底物的类型。在没有外源磷酸盐底物的情况下，细胞通过铀磷酸盐生物矿化与铀相互作用，在最初的48小时内铀的去除率达到98%。然而，在存在无机磷酸盐的情况下，铀溶解过程是细胞主要的铀相互作用机制，这表明了该菌株的磷酸盐溶解潜力。这些发现表明了该菌株在铀生物修复中的生物技术应用，这取决于磷酸盐底物：铀生物矿化（在无磷酸盐系统中）以及间接通过溶解含磷废物中的正磷酸盐来实现铀沉淀所需。
