Facing the combined pollution of antibiotics and heavy metals caused by livestock excrement and industrial effluents, how to use microbial technology to remove these pollutants simultaneously is an important research topic in environmental remediation. In addition, quick separation of the bacteria-water after remediation is also an urgent problem. In this study, we gradually developed a dual-bacteria microbial treatment technology capable of removing Pb(Ⅱ), Cd(Ⅱ) and common antibiotics, as well as self-settling after treatment. The key technology in this study mainly includes modifying the bacterial membrane proteins using Pb-binding protein PbrR, Cd-binding protein CadR and bacterial laccase CotA via surface-display technology to maximize the removal of Pb(Ⅱ), Cd(Ⅱ) and antibiotics, separately. Besides, the introduction of nanobody-antigen adhesion facilitated the self-settling in dual-bacterial system. Then, we studied its effectiveness in removing single pollutants, analyzed the influence of different heavy metal ions, and conducted detailed studies on the kinetics. Further characterization of heavy metal biosorption behavior was conducted using SEM, SEM-EDS, FTIR, and XPS techniques. Via protein fusion and dual vector expression, we constructed a dual-bacteria treatment system that could achieve rapid, selective removal of combined pollutants at a wide pH range temperature range, ultimately precipitating at bottom. Finally, molecular dynamics simulation was employed to elucidate the molecular mechanism underlying the selective biosorption by metal-binding proteins. The findings in this study hold significant implications for achieving selective pollutant removal using engineering bacteria in complex water environments.

中文翻译：

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双菌系统同步脱除水中抗生素和Pb（II.）/Cd（II.）的合理设计


面对畜禽粪便和工业废水造成的抗生素和重金属的混合污染，如何利用微生物技术同时去除这些污染物是环境修复中的重要研究课题。此外，修复后细菌-水的快速分离也是一个紧迫的问题。在本研究中，我们逐步开发了一种能够去除 Pb（II.）、Cd（II.） 和常见抗生素，以及处理后自沉降的双细菌微生物处理技术。本研究的关键技术主要包括利用 Pb 结合蛋白 PbrR、Cd 结合蛋白 CadR 和细菌漆酶 CotA 通过表面显示技术对细菌膜蛋白进行修饰，以最大限度地分别去除 Pb（II.）、Cd（II.） 和抗生素。此外，纳米抗体-抗原粘附的引入促进了双细菌系统中的自我沉降。然后，我们研究了其去除单一污染物的有效性，分析了不同重金属离子的影响，并对其动力学进行了详细研究。使用 SEM、SEM-EDS、FTIR 和 XPS 技术对重金属生物吸附行为进行了进一步表征。通过蛋白质融合和双载体表达，我们构建了双细菌处理系统，可以在较宽的 pH 范围温度范围内实现快速、选择性地去除组合污染物，最终在底部沉淀。最后，采用分子动力学模拟阐明金属结合蛋白选择性生物吸附的分子机制。本研究的结果对于在复杂水环境中使用工程细菌实现选择性污染物去除具有重要意义。