基于粉末微電極的銅綠假單胞菌陽極界面自介導(dǎo)電子傳遞機理研究
發(fā)布時間：2018-10-12 08:00
【摘要】：微生物燃料電池(microbial fuel cell,MFC)是一種利用微生物作為催化劑將有機物中的化學(xué)能轉(zhuǎn)化為電能的裝置。它將污水處理與電力生產(chǎn)有效的結(jié)合在一起,為能源和環(huán)境問題提供了新思路和新方法。MFC用可以自我復(fù)制再生的微生物替代了傳統(tǒng)化學(xué)燃料電池的貴金屬作為催化劑,同時微生物種類繁多、代謝途徑豐富且易調(diào)控,理論上能夠催化所有小分子有機物甚至部分無機物降解而產(chǎn)生能量,因而它是具有低成本、高效率、無污染等優(yōu)點,在污水處理、生態(tài)修復(fù)和便攜式能源等領(lǐng)域具有巨大的應(yīng)用前景�，F(xiàn)階段,MFC的功率密度相對較低,這主要是由于細菌代謝導(dǎo)致的活化損失,尤其是低效的電子轉(zhuǎn)移比例(庫倫效率)和電子轉(zhuǎn)移速率(電流產(chǎn)量),因此而限制了其商業(yè)化應(yīng)用。就此而言,深入了解微生物胞外電子傳遞過程對微生物燃料電池的實施十分重要。在微生物燃料電池中,無論電子傳遞途徑如何,生物膜的形成對于電池產(chǎn)電效率具有至關(guān)重要的影響。目前,由于驗證手段和方法的限制,微生物燃料電池陽極界面電子傳遞過程研究仍然相對滯后。對于生物膜在依賴自分泌電子介體所介導(dǎo)胞外電子傳遞中的作用尚不清楚。為了明確陽極界面電子傳遞機制,尤其是僅依賴自分泌介體進行界面電子傳遞機制中陽極生物膜的作用,需要發(fā)展一種簡便易行的新方法對產(chǎn)電過程中陽極室內(nèi)的電子介體進行實時分析,同時對生物膜形成與產(chǎn)電性能之間進行系統(tǒng)研究和深入探討。本研究以銅綠假單胞菌(Pseudomonas aeruginosa ATCC 9027)為產(chǎn)電菌株,通過粉末微電極的應(yīng)用和合適的分析方法的選擇,實現(xiàn)不同位置的陽極液中電子介體(吩嗪)的實時監(jiān)測和利用生物膜抑制劑(魚腥草素鈉)抑制生物膜的形成,并通過電化學(xué)分析方法進行研究,提出銅綠假單胞菌胞外電子傳遞機理。主要研究內(nèi)容和結(jié)果如下:1.吩嗪作為銅綠假單胞菌一種代謝產(chǎn)物,在MFC中,吩嗪是銅綠假單胞菌的電子介體可以將電子傳遞到陽極,從而實現(xiàn)放電。但是目前研究仍然沒有確定吩嗪如何影響MFC的放電。本研究在MFC操作過程,利用粉末微電極高靈敏度對MFC陽極液中P.aeruginosa分泌的吩嗪濃度變化進行實時監(jiān)測。采用粉末微電極實時監(jiān)測過程中可以看到吩嗪在電位-0.45 V處存在一對氧化還原峰,且峰電流的大小隨著時間不斷發(fā)生變化,這是由于P.aeruginosa生長過程中吩嗪濃度先是逐漸增加至平臺期,120小時后開始下降。與此同時,在距離MFC陽極不同位置處,吩嗪的呈現(xiàn)不同的濃度大小,在陽極近端吩嗪的濃度小于遠端。所以由此推斷吩嗪濃度的變化不僅決定于MFC放電過程中細菌的代謝,而且受陽極表面生物膜的影響。因此,本研究提出一種關(guān)于MFC放電過程吩嗪的分泌情況以及吩嗪在胞外介導(dǎo)P.aeruginosa電子傳遞過程的機理,且提供一種簡便高效準確的研究手段用于MFC自介導(dǎo)胞外電子傳遞過程的研究。2.細菌生物膜在MFC細菌放電過程中尤其是放電初期扮演著十分重要的角色。然而到目前為止生物膜提高MFC產(chǎn)電電壓的詳細機理并不是特別清楚,尤其對于僅僅依靠自介導(dǎo)電子介體進行胞外電子傳遞的細菌。本研究利用生物膜抑制劑(魚腥草素鈉)用于在MFC中構(gòu)建P.aeruginosa“無膜”陽極,同時幾乎不影響細菌的生長。然后通過比較MFC中“有膜”和“無膜”陽極的放電電流密度、吩嗪濃度變化和陽極的電化學(xué)分析,可以看到生物膜可以顯著提高電池的放電電流。這主要是由于生物膜的形成不僅可以使更多的微生物用于催化反應(yīng)而且通過在陽極表面富集大量的電子介體實現(xiàn)快速界面電子傳遞。與此同時,陽極液中吩嗪濃度變化可以在MFC放電過程初期作為判斷生物膜生長情況的指標。本研究證明了生物膜在MFC放電過程中可以通過富集電子介體(吩嗪)提高電極界面介體濃度而實現(xiàn)胞外電子傳遞快速有效的進行。
[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，
本文編號：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，
本文編號：2265378
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