铁锰代谢菌胞外氧化还原驱动的矿物形成与应用

发布时间：2018-01-28 17:35

  本文关键词： 铁锰代谢菌 硒铁成矿 生物合成材料 光热治疗 环丙沙星降解 元素循环 氧化还原驱动力　出处：《中国科学技术大学》2017年硕士论文　论文类型：学位论文

【摘要】：铁锰代谢菌所具有的氧化还原驱动力是其被应用于环境领域的基础,虽然已有一些关于铁锰代谢菌在环境领域应用的报道,但是对其在有微量元素成矿机制、元素循环与污染物降解中作用的认识尚不够清晰。本论文主要探索几种模式铁锰代谢菌在微量元素成矿、材料生物合成以及污染物降解中的作用。论文的主要内容和结果如下:1.以环境中含量较高且广受关注的Se作为微量元素代表、水合氧化铁作为自然界中广泛存在的铁矿物代表,以铁锰还原菌Geobacter sulfurreducens为对象,开展了铁锰还原菌介导的微量元素成矿试验。通过一系列固相表面的表征,证明了 Geobacter可以实现水合铁与Se032-的共还原,且在较长的时间尺度下(120天)能够在HFO表面形成FeSe复合物。此外,还证明了Geobactr的铁还原过程受电子供体种类和电子穿梭体存在与否的影响,发现以氢气作为电子供体能够加快铁还原速率但是降低细菌活性,电子穿梭体的加入则能够显著加快铁的还原速率,弥补了乙酸钠作为电子供体相对于氢气的不足。2.以铁锰还原菌ShewanellaoneidensisMR-1的胞外还原能力为基础,充分发挥其能够利用多种电子供体的优势,胞外合成纳米材料。将S2O32-作为S源还原生成S2-,后与Cu2+结合合成了 CuS纳米颗粒;通过投加原料比的调控,显著简化了纳米材料的分离纯化步骤,得到了尺寸均一、小粒径、高分散的CuS纳米颗粒;通过对CuS纳米颗粒光热性能的检测表明,该生物合成颗粒具有优于贵金属的光热转化效率,且拥有优异的循环稳定性;利用人肺癌细胞A594R的体外实验则显示出S.oneidensis MR-1生物合成的CuS纳米颗粒能够在不损伤正常组织细胞的情况下高效杀死癌细胞。3.以锰氧化物氧化分解环丙沙星(CIP)为切入点,构建了生物强化的污染物化学降解系统。利用PseudomonasputidaMnB-1氧化Mn~(2+)形成MnO_2的能力,通过投加Mn~(2+)获得高反应活性的MnO_2颗粒,从而完成环丙沙星的高效降解;观察到MnO_2的存在使细菌保持活性,实现将环丙沙星还原的MnO_2的再次氧化,从而构成了锰元素的微生物循环,进而实现了环丙沙星的非生物降解;Mn(Ⅲ)络合剂的加入导致环丙沙星降解速率的降低,从而证明Mn(Ⅲ)在这该循环反应中所起的促进作用。
[Abstract]:The redox driving force of ferromanganese metabolites is the basis of their application in the field of environment. Although there have been some reports on the application of ferromanganese metabolites in the field of environment, there are metallogenic mechanisms of trace elements in them. The role of element cycling and pollutant degradation is not clear. In this paper, several models of iron and manganese metabolism bacteria in trace element mineralization. The main contents and results of this paper are as follows: 1. The high content of se in the environment and its widespread concern are taken as the representative of trace elements. As the representative of iron minerals widely existed in nature, hydrated iron oxide takes ferromanganese reducing bacteria Geobacter sulfurreducens as the object. Through a series of solid surface characterization, it is proved that Geobacter can realize the co-reduction of iron hydrate and Se032-. In addition, FeSe complex can be formed on the surface of HFO at a longer time scale (120 days). It is also proved that the process of iron reduction of Geobactr is affected by the type of electron donor and the existence of electron shuttle. It is found that hydrogen can accelerate the rate of iron reduction but reduce the activity of bacteria. The addition of electron shuttle can significantly accelerate the reduction rate of iron. It makes up the deficiency of sodium acetate as electron donor relative to hydrogen. It is based on the extracellular reduction ability of ferromanganese reducing bacteria ShewanellaoneidensisMR-1. S2O32- was used as the source of S to form S2-and then combined with Cu2 to synthesize CuS nanoparticles. By adjusting the ratio of raw materials, the separation and purification of nanomaterials were greatly simplified, and CuS nanoparticles with uniform size, small particle size and high dispersion were obtained. The photothermal properties of CuS nanoparticles showed that the biosynthetic particles were superior to precious metals in photothermal conversion efficiency and had excellent cycling stability. In vitro experiments using human lung cancer cell line A594R showed that S. oneidensis. The CuS nanoparticles synthesized by MR-1 can efficiently kill cancer cells without damaging normal tissue cells. The oxidative decomposition of ciprofloxacin (ciprofloxacin) with manganese oxide (MNO). CIP) as the entry point. A bioenhanced chemical degradation system for pollutants was constructed. The ability of PseudomonasputidaMnB-1 to oxidize Mn~(2 to form MnO_2 was established. The highly reactive MnO_2 particles were obtained by adding Mn~(2) to achieve the efficient degradation of ciprofloxacin. It was observed that the presence of MnO_2 kept the bacteria active and reoxidized the MnO_2 that reduced ciprofloxacin, thus forming the microbial cycle of manganese. The non-biodegradation of ciprofloxacin was realized. The addition of mn (鈪，

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