CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China.
Environ Sci Technol. 2020 Sep 1;54(17):10713-10721. doi: 10.1021/acs.est.0c02175. Epub 2020 Aug 17.
Biotransformation of selenite to valuable elemental selenium nanoparticles (Se) is a promising avenue to remediate seleniferous environments and simultaneously recover selenium (Se). However, the underlying oxyanion competition and selenite transformation mechanism in prokaryotes are poorly understood. In this work, the impacts of phosphate on selenite uptake and transformation were elucidated with and its mutant deficient in phosphate transport as model microbial strains. Selenite uptake was inhibited by phosphate in . Moreover, the transformation of internalized Se was shifted from Se to toxic organo-Se with elevated phosphate levels, as evidenced by the linear combination fit analysis of the Se K-edge X-ray absorption near-edge structure. Such a phosphate-regulated selenite biotransformation process was mainly assigned to the competitive uptake of phosphate and selenite, which was primarily mediated by a low affinity phosphate transporter (PitA). Under phosphate-deficient conditions, the cells not only produced abundant Se nanoparticles but also maintained good cell viability. These findings provide new insights into the phosphate-regulated selenite biotransformation by prokaryotes and contribute to the development of new processes for bioremediating Se-contaminated environments, as well as bioassembly of Se.
亚硒酸盐到有价值的元素硒纳米颗粒（Se）的生物转化是修复硒污染环境并同时回收硒（Se）的一种很有前途的途径。然而，原核生物中亚硒酸盐的氧阴离子竞争和转化机制还了解甚少。在这项工作中，我们以 和其磷酸盐转运缺陷突变体作为模型微生物菌株，阐明了磷酸盐对亚硒酸盐摄取和转化的影响。磷酸盐会抑制 中的亚硒酸盐摄取。此外，随着磷酸盐水平的升高，内部 Se 的转化从 Se 转移到有毒的有机-Se，这可以通过 Se K 边缘 X 射线吸收近边缘结构的线性组合拟合分析得到证明。这种受磷酸盐调控的亚硒酸盐生物转化过程主要归因于磷酸盐和亚硒酸盐的竞争摄取，这主要是由低亲和力磷酸盐转运蛋白（PitA）介导的。在磷酸盐缺乏的条件下，细胞不仅产生了丰富的 Se 纳米颗粒，而且保持了良好的细胞活力。这些发现为原核生物中磷酸盐调控的亚硒酸盐生物转化提供了新的见解，并有助于开发新的过程来生物修复硒污染的环境，以及硒的生物组装。
