基于粉末微电极的铜绿假单胞菌阳极界面自介导电子传递机理研究
发布时间：2018-10-12 08:00
【摘要】：微生物燃料电池(microbial fuel cell,MFC)是一种利用微生物作为催化剂将有机物中的化学能转化为电能的装置。它将污水处理与电力生产有效的结合在一起,为能源和环境问题提供了新思路和新方法。MFC用可以自我复制再生的微生物替代了传统化学燃料电池的贵金属作为催化剂,同时微生物种类繁多、代谢途径丰富且易调控,理论上能够催化所有小分子有机物甚至部分无机物降解而产生能量,因而它是具有低成本、高效率、无污染等优点,在污水处理、生态修复和便携式能源等领域具有巨大的应用前景。现阶段,MFC的功率密度相对较低,这主要是由于细菌代谢导致的活化损失,尤其是低效的电子转移比例(库伦效率)和电子转移速率(电流产量),因此而限制了其商业化应用。就此而言,深入了解微生物胞外电子传递过程对微生物燃料电池的实施十分重要。在微生物燃料电池中,无论电子传递途径如何,生物膜的形成对于电池产电效率具有至关重要的影响。目前,由于验证手段和方法的限制,微生物燃料电池阳极界面电子传递过程研究仍然相对滞后。对于生物膜在依赖自分泌电子介体所介导胞外电子传递中的作用尚不清楚。为了明确阳极界面电子传递机制,尤其是仅依赖自分泌介体进行界面电子传递机制中阳极生物膜的作用,需要发展一种简便易行的新方法对产电过程中阳极室内的电子介体进行实时分析,同时对生物膜形成与产电性能之间进行系统研究和深入探讨。本研究以铜绿假单胞菌(Pseudomonas aeruginosa ATCC 9027)为产电菌株,通过粉末微电极的应用和合适的分析方法的选择,实现不同位置的阳极液中电子介体(吩嗪)的实时监测和利用生物膜抑制剂(鱼腥草素钠)抑制生物膜的形成,并通过电化学分析方法进行研究,提出铜绿假单胞菌胞外电子传递机理。主要研究内容和结果如下:1.吩嗪作为铜绿假单胞菌一种代谢产物,在MFC中,吩嗪是铜绿假单胞菌的电子介体可以将电子传递到阳极,从而实现放电。但是目前研究仍然没有确定吩嗪如何影响MFC的放电。本研究在MFC操作过程,利用粉末微电极高灵敏度对MFC阳极液中P.aeruginosa分泌的吩嗪浓度变化进行实时监测。采用粉末微电极实时监测过程中可以看到吩嗪在电位-0.45 V处存在一对氧化还原峰,且峰电流的大小随着时间不断发生变化,这是由于P.aeruginosa生长过程中吩嗪浓度先是逐渐增加至平台期,120小时后开始下降。与此同时,在距离MFC阳极不同位置处,吩嗪的呈现不同的浓度大小,在阳极近端吩嗪的浓度小于远端。所以由此推断吩嗪浓度的变化不仅决定于MFC放电过程中细菌的代谢,而且受阳极表面生物膜的影响。因此,本研究提出一种关于MFC放电过程吩嗪的分泌情况以及吩嗪在胞外介导P.aeruginosa电子传递过程的机理,且提供一种简便高效准确的研究手段用于MFC自介导胞外电子传递过程的研究。2.细菌生物膜在MFC细菌放电过程中尤其是放电初期扮演着十分重要的角色。然而到目前为止生物膜提高MFC产电电压的详细机理并不是特别清楚,尤其对于仅仅依靠自介导电子介体进行胞外电子传递的细菌。本研究利用生物膜抑制剂(鱼腥草素钠)用于在MFC中构建P.aeruginosa“无膜”阳极,同时几乎不影响细菌的生长。然后通过比较MFC中“有膜”和“无膜”阳极的放电电流密度、吩嗪浓度变化和阳极的电化学分析,可以看到生物膜可以显著提高电池的放电电流。这主要是由于生物膜的形成不仅可以使更多的微生物用于催化反应而且通过在阳极表面富集大量的电子介体实现快速界面电子传递。与此同时,阳极液中吩嗪浓度变化可以在MFC放电过程初期作为判断生物膜生长情况的指标。本研究证明了生物膜在MFC放电过程中可以通过富集电子介体(吩嗪)提高电极界面介体浓度而实现胞外电子传递快速有效的进行。
[Abstract]:Microbial fuel cell (MFC) is a device that uses microorganism as catalyst to convert chemical energy in organic matter into electric energy. It combines sewage treatment with electric power production effectively, and provides new ideas and new methods for energy and environmental problems. MFC can replace traditional chemical fuel cell noble metal as catalyst by using microorganisms capable of self-replicating and regenerating, and meanwhile, the microbial species are various, the metabolic pathway is abundant and easy to regulate, and the theory can catalyze all small molecule organic matters and even partially inorganic matters to degrade to generate energy, Therefore, it has the advantages of low cost, high efficiency, no pollution and the like, and has great application prospect in the fields of sewage treatment, ecological restoration and portable energy. At this stage, the power density of MFC is relatively low, mainly due to the activation loss caused by bacterial metabolism, especially inefficient electron transfer ratio (electron transfer efficiency) and electron transfer rate (current yield), thus limiting its commercial application. In this regard, an in-depth understanding of the external electron transfer process of microbial cells is of great importance to the implementation of microbial fuel cells. In microbial fuel cells, biofilm formation is of critical importance to cell electricity efficiency, regardless of the electron transport pathway. At present, the research on the electron transfer process in the anode interface of microbial fuel cell is still relatively lagging due to the limitation of verification methods and methods. The effect of biofilm on electron transfer mediated by autocrine electron mediator is not clear. in ord to clarify that electron transfer mechanism of the anode interface, in particular to the effect of the anode biological membrane in the interface electron transfer mechanism only depend on the autocrine mediator, a simple and convenient method is needed to carry out real-time analysis on the electron mediator in the anode cham in the electric production process, At the same time, the system research and discussion about the formation of biofilm and electrical properties were carried out. Pseudomonas aeruginosa ATCC 9027 was used as an electric strain, and the application of powder microelectrode and the selection of suitable analytical methods were studied. In order to realize the real-time monitoring of electron mediator in anode liquid at different positions and the formation of biofilm by using biofilm inhibitor (sodium cordate sodium), the mechanism of extracellular electron transfer of Pseudomonas aeruginosa was proposed by electrochemical analysis. The main contents and results are as follows: 1. As a metabolite of Pseudomonas aeruginosa in MFC, the electron mediator of Pseudomonas aeruginosa in MFC can transfer electron to the anode so as to realize discharge. But the current study still hasn't yet been able to determine how it affects the discharge of MFC. In this study, the concentration of P. aeruginosa secreted by the MFC anode was monitored in real time by the high sensitivity of the powder microelectrodes during MFC operation. A pair of redox peaks at potential-0. 45V can be seen in the real-time monitoring of powder microelectrode, and the magnitude of peak current changes with time. At the same time, at different locations from the MFC anode, the concentration of the hydrogen bromide at the anode proximal end is smaller than the distal end. Therefore, it is concluded that the change of the concentration of the anode slime not only determines the metabolism of bacteria during MFC discharge but also is influenced by the biofilm on the surface of the anode. Therefore, this study provides a simple and efficient method for the study of MFC self-mediated extracellular electron transfer process. Bacterial biofilm plays a very important role in MFC bacterial discharge, especially in the early stage of discharge. However, the detailed mechanism of improving the electrical voltage produced by MFC so far is not particularly clear, especially for bacteria that rely solely on self-mediated electron mediator for extracellular electron transfer. Biofilm inhibitor (sodium cordate sodium) was used to construct P. aeruguinosa 鈥渕embraneless鈥，
本文编号：2265378
[Abstract]:Microbial fuel cell (MFC) is a device that uses microorganism as catalyst to convert chemical energy in organic matter into electric energy. It combines sewage treatment with electric power production effectively, and provides new ideas and new methods for energy and environmental problems. MFC can replace traditional chemical fuel cell noble metal as catalyst by using microorganisms capable of self-replicating and regenerating, and meanwhile, the microbial species are various, the metabolic pathway is abundant and easy to regulate, and the theory can catalyze all small molecule organic matters and even partially inorganic matters to degrade to generate energy, Therefore, it has the advantages of low cost, high efficiency, no pollution and the like, and has great application prospect in the fields of sewage treatment, ecological restoration and portable energy. At this stage, the power density of MFC is relatively low, mainly due to the activation loss caused by bacterial metabolism, especially inefficient electron transfer ratio (electron transfer efficiency) and electron transfer rate (current yield), thus limiting its commercial application. In this regard, an in-depth understanding of the external electron transfer process of microbial cells is of great importance to the implementation of microbial fuel cells. In microbial fuel cells, biofilm formation is of critical importance to cell electricity efficiency, regardless of the electron transport pathway. At present, the research on the electron transfer process in the anode interface of microbial fuel cell is still relatively lagging due to the limitation of verification methods and methods. The effect of biofilm on electron transfer mediated by autocrine electron mediator is not clear. in ord to clarify that electron transfer mechanism of the anode interface, in particular to the effect of the anode biological membrane in the interface electron transfer mechanism only depend on the autocrine mediator, a simple and convenient method is needed to carry out real-time analysis on the electron mediator in the anode cham in the electric production process, At the same time, the system research and discussion about the formation of biofilm and electrical properties were carried out. Pseudomonas aeruginosa ATCC 9027 was used as an electric strain, and the application of powder microelectrode and the selection of suitable analytical methods were studied. In order to realize the real-time monitoring of electron mediator in anode liquid at different positions and the formation of biofilm by using biofilm inhibitor (sodium cordate sodium), the mechanism of extracellular electron transfer of Pseudomonas aeruginosa was proposed by electrochemical analysis. The main contents and results are as follows: 1. As a metabolite of Pseudomonas aeruginosa in MFC, the electron mediator of Pseudomonas aeruginosa in MFC can transfer electron to the anode so as to realize discharge. But the current study still hasn't yet been able to determine how it affects the discharge of MFC. In this study, the concentration of P. aeruginosa secreted by the MFC anode was monitored in real time by the high sensitivity of the powder microelectrodes during MFC operation. A pair of redox peaks at potential-0. 45V can be seen in the real-time monitoring of powder microelectrode, and the magnitude of peak current changes with time. At the same time, at different locations from the MFC anode, the concentration of the hydrogen bromide at the anode proximal end is smaller than the distal end. Therefore, it is concluded that the change of the concentration of the anode slime not only determines the metabolism of bacteria during MFC discharge but also is influenced by the biofilm on the surface of the anode. Therefore, this study provides a simple and efficient method for the study of MFC self-mediated extracellular electron transfer process. Bacterial biofilm plays a very important role in MFC bacterial discharge, especially in the early stage of discharge. However, the detailed mechanism of improving the electrical voltage produced by MFC so far is not particularly clear, especially for bacteria that rely solely on self-mediated electron mediator for extracellular electron transfer. Biofilm inhibitor (sodium cordate sodium) was used to construct P. aeruguinosa 鈥渕embraneless鈥，
本文编号：2265378
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