利用细菌生物氧化作用制备锰基键电池电极材料及降解毒死蜱的研究

发布时间：2018-05-11 12:12

本文选题：锰氧化矿物 + 表面展示　；参考：《华中农业大学》2017年博士论文

【摘要】：氧化锰矿物是经化学和生物氧化Mn~(2+)后形成的、具有高反应活性的一类金属矿物,通常以较高的含量和以球状、块状或不规则形等形状的聚集体的形式分布于土壤和水体沉积物中,能强烈地吸附多种重金属、放射性元素和微量元素等,影响或直接决定着它们在环境中的浓度、形态、迁移和转化过程,从而在元素的生物地球物化流动循环中充当重要环节。大量的研究已证实,多种微生物类群,尤其锰氧化细菌和锰氧化真菌类群,是自然界中氧化锰矿物形成的主要驱动力。本文基于实验室一株锰氧化假单胞菌(Pseudominas sp.)T34菌株和另一株表面展示多铜氧化酶的恶臭假单胞菌(Pseudomonas putida)重组菌MB285均可在Mn~(2+)诱导下形成生物锰氧化矿物聚集体的特性,制备了由Co~(2+)/Ni~(2+)等外源金属掺杂的多种纳米-微米级生物锰氧化物聚集体并进行了多重形貌与性能表征测定,然后利用聚集体作为生物模板进一步制备了MnO基质的中空、多孔和高氧化势能的电化学材料并测定了用于锂离子电池负极材料时的电化学性能。此外,利用多铜氧化酶对有机化合物的降解活性,研究了表面展示多铜氧化酶工程菌MB285菌株对有机磷农药毒死蜱的完全降解活性。其主要研究内容和结果如下:1.从实验室保藏的具有锰氧化活性的野生菌株中筛选到能形成锰氧化物聚集体的假单胞菌T34,另发现表面展示多铜氧化酶的恶臭假单胞菌MB285在含Mn~(2+)环境下连续培养时也具有类似活性。在培养过程中分别添加Co~(2+)和Ni~(2+),分析了氧化物矿化过程中这两种金属离子对野生菌株T34菌株和工程菌MB285菌株锰氧化活性的影响,证明了金属离子在锰氧化矿物形成的过程中与其存在互作。对T34和MB285形成的聚集体表观形貌和主要物相进行了多重表征,发现T34生成的聚集体为层状堆叠结构,MB285生成的聚集体为微球形;两种聚集体均为介孔材料,具有较高的比表面积,主要成分仍以生物质为主;形成的聚集体为高价态锰氧化物分散在细菌和胞外多糖等生物质中的微米-纳米结构。分析了影响锰氧化活性的多种因素尤其是锰氧化酶在锰氧化活动中的重要作用,明确了锰氧化物矿化作用的优化条件。2.以T34菌株和工程菌MB285形成的生物锰氧化物聚集体作为前驱物,利用生物矿化作用和金属离子沉降槽的特性实现了温和条件下Co和Ni元素的掺杂,然后利用生物模板法将聚集体前驱物在Ar气环境中以不同温度进行高温碳化,制备了由Co和Ni掺杂的多种复合材料。通过X射线光电子能谱、相组成和精细结构分析技术证实这些材料为以MnO纳米晶体为基相、多相彼此掺杂并共同镶嵌于碳基质的多孔复合物材料。研究表明,随碳化温度的提高,复合材料的石墨化程度逐渐提高,而适当的碳化温度可使材料形成中空和多孔形貌。对各温度下合成的材料作为锂离子电池负极材料的电化学循环性能和倍率性能进行比较。由于具有独特的中空多孔结构和呈多相掺杂的状态,由T34菌株制备的复合材料CMC-Co和CMC-Ni在循环过程中展现了良好的循环稳定性和可逆比容量,CMC-Co和CMC-Ni保留的可逆放电容量分别为650 m Ah g~(-1)和547.2 m Ah g~(-1)(0.1 Ag~(-1),50个循环)。由工程菌MB285制备的复合材料CMB-Co和CMB-Ni的比容量分别为361.44和379.29 m Ah g~(-1)(0.1 Ag~(-1),50个循环)。所有制备的掺杂Ni氧化物材料的循环稳定性都有大幅度的提高,并且在循环性能的测试中具备接近零容量损失的特性(200个循环),极化现象消失。3.研究了工程菌MB285对农药毒死蜱的生物降解能力。通过高效液相色谱和气相色谱-质谱联用技术对降解产物的组成进行分析的结果表明,MB285能够完全降解毒死蜱;而非细胞表面固定的游离多铜氧化酶仅能将毒死蜱转化为3,5,6-三氯-2-吡啶醇。工程菌MB285降解反应过程中存在两种中间代谢物,即3,5,6-三氯-2-吡啶醇和磷酸二乙酯,反映该菌对毒死蜱的完全降解是通过表面多铜氧化酶和部分细胞酶类的联合作用和分多步反应来实现的。降解反应可以在较宽范围的pH值(2?7)和温度(5?55℃)下进行且不需要Cu2+参与。使用秀丽隐杆线虫(Caenorhabditis elegans)作为指示生物的生物测定实验表明含毒死蜱培养物通过工程菌MB285降解后发生了完全脱毒作用。此外,该工程菌展示了可重复利用的高降解活性和进行连续降解反应的良好循环性能,以及在自然废水体系中对毒死蜱的强降解能力。因此,显示了在生物修复毒死蜱残留物污染方面的应用潜力。
[Abstract]:A mineral of manganese oxide, formed after chemical and biological oxidation of Mn~ (2+), has a highly reactive class of metal minerals, usually distributed in soil and water sediments in the form of higher content and aggregates of spherical, lumpy, or irregular shapes, and can strongly adsorb a variety of heavy metals, radioactive elements and trace elements, etc. It affects or directly determines their concentration, morphology, migration and transformation in the environment, and thus acts as an important link in the biological and physical flow cycle of the elements. A large number of studies have proved that a variety of microbial groups, especially manganese oxide bacteria and manganese oxide fungi, are the main driving forces of the formation of manganese oxide minerals in nature. Based on a laboratory strain of Pseudominas sp. (Pseudominas sp.) and another strain of Pseudomonas sp. (Pseudomonas putida), a recombinant strain of Pseudomonas aeruginosa (Pseudomonas putida) can be induced by Mn~ (2+) to form a biological manganese oxide aggregate, and a variety of exogenous metals, such as Co~ (2+) /Ni~ (2+) and so on, are prepared. The multimorphologies and properties of manganese oxide aggregates in rice micron grade were measured. Then the electrochemical properties of the MnO matrix were further prepared by using the aggregates as a template for the hollow, porous and high oxidation potential, and the electrochemical properties of the anode materials used in lithium ion batteries were measured. The degradation activity of organic compounds was studied. The total degradation activity of MB285 strain on the organophosphorus pesticide chlorpyrifos on the surface was studied. The main contents and results were as follows: 1. the Pseudomonas T34, which could form manganese oxide aggregates, was screened from the wild strains with manganese oxide activity preserved in the laboratory. It was found that the Pseudomonas malodum MB285 on the surface showed a similar activity in Mn~ (2+) environment. Co~ (2+) and Ni~ (2+) were added to the culture process, and the effects of these two metal ions on the manganese oxidation activity of the wild strain T34 strain and the MB285 strain of the engineering bacteria were analyzed in the process of oxide mineralization. The metal ions interacted with them during the formation of manganese oxide minerals. The aggregated surface morphology and main phase of T34 and MB285 were characterized. It was found that the aggregates formed by T34 were layered structure, and the aggregates formed by MB285 were microspheres, and the two aggregates were mesoporous materials with high specific surface area. The main components are mainly biomass, and the formed aggregates are micron and nanoscale structures of high valence manganese oxides dispersed in bacteria and extracellular polysaccharide and other biomass. The important effects of manganese oxidases on manganese oxidation activities are analyzed, and the optimal conditions for manganese oxide mineralization are confirmed by.2.. The biological manganese oxide aggregates formed by T34 strain and engineering bacteria MB285 are used as precursors. The doping of Co and Ni elements in mild conditions is realized by the properties of biomineralization and the characteristics of metal ion sink. Then, the polymer precursor in the Ar gas environment is carbonized at different temperatures by the biological template method, and Co is prepared by Co. And Ni doped composite materials. Through X ray photoelectron spectroscopy, phase composition and fine structure analysis, it is proved that these materials are porous composite materials which are doped with MnO nanocrystals and are multiphase and embedded in carbon matrix. The study shows that the degree of graphitization of the composites increases with the increase of carbonation temperature. The suitable carbonization temperature can make the material hollow and porous morphology. The materials synthesized at various temperatures are compared to the electrochemical cycle properties and ratio properties of the anode materials for lithium ion batteries. Because of the unique hollow porous structure and the state of multiphase doping, the composite material CMC-Co and CMC-Ni prepared by the T34 strain can be used. The cyclic stability and reversible specific capacity were shown in the cycle. The reversible discharge capacity retained by CMC-Co and CMC-Ni were 650 m Ah g~ (-1) and 547.2 m Ah g~ (-1) (-1), 50 cycles, respectively. The composite materials prepared by engineering bacteria were 361.44 and 379.29 respectively (0.1) and 50 respectively. Cycle). The cyclic stability of all the doped Ni oxide materials has been greatly improved, and there is a characteristic of close to zero loss in the cycle performance test (200 cycles). The polarization phenomenon disappears.3. to study the biodegradability of the engineering bacteria MB285 to the pesticide chlorpyrifos by high performance liquid chromatography and gas chromatography - The analysis of the composition of the degradation products by mass spectrometry shows that MB285 can completely reduce the detoxification of chlorpyrifos, and the non cell surface immobilized free polycupric oxidase can only convert chlorpyrifos to 3,5,6- three chloro -2- pyridine. There are two intermediate metabolites, namely, 3,5,6- three chloro -2- pyridine alcohol and phosphorus in the MB285 degradation process of engineering bacteria. Acid two ethyl ester, reflecting the complete degradation of chlorpyrifos by the bacteria by the combination of surface copper oxidase and partial cell enzymes and multistep reactions. The degradation reaction can be carried out at a wider range of pH values (2? 7) and temperature (5? 55 degrees) without the need of Cu2+ reference. The use of Caenorhabditis elegans as a cryptonematode. Biometric tests indicating that the bioassay of chlorpyrifos showed complete detoxification after the degradation of the engineered strain MB285. In addition, the engineered bacteria showed good reproducibility and good cycling performance for continuous degradation, as well as the strong degradation ability of Chlorpyrifos in the natural waste water system. The potential application of bioremediation of chlorpyrifos residues is shown.

【学位授予单位】：华中农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X592;TM912

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