本文選題：產(chǎn)電微生物　切入點：CymA依賴性　出處：《江蘇大學(xué)》2017年碩士論文

【摘要】：伴隨著近年來在環(huán)境治理、納米材料合成和生物能源等領(lǐng)域的廣泛應(yīng)用,產(chǎn)電微生物越來越受到研究者的關(guān)注。Shewanella是一種典型的產(chǎn)電微生物。它擁有強大的厭氧異化呼吸能力,具有廣泛的環(huán)境適應(yīng)性。但是目前對于Shewanella跨膜電子傳遞路徑選擇的研究還不是很透徹,特別是關(guān)于內(nèi)膜蛋白CymA在跨膜電子傳遞過程中的作用尚存在許多爭議。另外,電子胞外釋放能力對于產(chǎn)電微生物的環(huán)境應(yīng)用具有重要影響。但是目前已建立的評估微生物胞外電子釋放能力的方法存在諸多缺陷,亟需發(fā)展一種便捷、高效、便宜的新方法來評估微生物的胞外產(chǎn)電能力。因此,本論文以模式產(chǎn)電微生物Shewanella oneidensis MR-1為研究對象,探究胞外電子釋放過程對胞內(nèi)電子傳遞途徑選擇的影響,并在此基礎(chǔ)上建立了一種基于染料胞外還原的高通量比色法用以微生物胞外產(chǎn)電效能的高效評估。本研究初步得到以下幾個結(jié)論:(1)胞內(nèi)電子傳遞途徑的選擇受到胞外電子釋放過程的影響。胞外電子受體性質(zhì)決定了c型細(xì)胞色素CymA在電子跨膜傳遞過程中的重要性。CymA對于易利用的檸檬酸鐵還原具有重要作用,但是對于難利用的Fe_2O_3胞外還原作用不大。通過添加胞外電子遞質(zhì)、提高檸檬酸鐵濃度以及增加電極電勢,加大胞外電子的釋放速度,都能提高CymA在跨膜電子轉(zhuǎn)運過程中的重要性。因此在胞外高電子傳遞速率條件下,胞內(nèi)電子傳遞過程對CymA依賴性比較大。而在低電子釋放速率條件下,其他的電子途徑可以彌補CymA缺失的影響。(2)微生物胞外電子釋放能力可以通過基于染料胞外還原的比色法進行高通量評估。實驗證明不能進入細(xì)胞的強極性染料甲基橙(MO)和萘酚綠B(NGB)可以作為評估微生物胞外產(chǎn)電能力的指示劑。在厭氧條件下監(jiān)測染料胞外還原速率不僅可以快速評估不同種微生物的胞外產(chǎn)電能力,還能區(qū)分出同種微生物的不同突變體之間產(chǎn)電能力的差異�；钚晕勰嘀械幕旌暇簩O脫色效能與MFC產(chǎn)電趨勢相耦合,進一步證明該方法不但可以評估純菌的胞外產(chǎn)電能力,還可以評估混合菌群的胞外產(chǎn)電能力。此外,該方法還能優(yōu)化碳源、溫度等實驗條件以提高微生物的胞外產(chǎn)電效能。因此本論文中所建立的高通量比色評估方法是一種簡單方便、準(zhǔn)確可靠、具有多功能利用的新型方法。
[Abstract]:In recent years, with the extensive application in the fields of environmental control, nano-material synthesis and bioenergy, the electroproducing microorganism has been paid more and more attention by researchers. Shewanella is a typical electric-producing microorganism. It has strong anaerobic dissimilatory respiration ability. However, the study of Shewanella transmembrane electron transport path selection is not very thorough, especially about the role of membrane protein CymA in the transmembrane electron transport process. In addition, there are still many controversies on the role of membrane protein CymA in the transmembrane electron transport process. The ability of extracellular electron release plays an important role in the environmental application of electrically producing microbes. However, there are many defects in the existing methods for evaluating the ability of electron release of microbes outside the cell, so it is necessary to develop a convenient and efficient method. Therefore, Shewanella oneidensis MR-1, a model electroproducing microorganism, was used to study the effect of extracellular electron release on the selection of intracellular electron transport pathway. On this basis, a high throughput colorimetric method based on dye extracellular reduction was established for the efficient evaluation of the extracellular electricity production efficiency of microorganisms. In this study, the following conclusions were preliminarily obtained: 1) the selection of intracellular electron transport pathway was evaluated. Effect of extracellular electron release process. The properties of extracellular electron receptors determine the importance of type c cytochrome CymA in electron transmembrane transport. CymA plays an important role in the readily available reduction of ferric citrate. By adding extracellular electron transmitters, increasing the concentration of ferric citrate and increasing the potential of electrode, the release rate of extracellular electrons was increased. Both can increase the importance of CymA in the transmembrane electron transport process. Therefore, at high extracellular electron transfer rate, the intracellular electron transfer process is highly dependent on CymA, but at low electron release rate, Other electron pathways can compensate for the loss of CymA. 2) the extracellular electron release ability of microorganisms can be evaluated by colorimetric method based on dye extracellular reduction. Under anaerobic conditions, monitoring the rate of extracellular reduction of dyes can not only rapidly evaluate the extracellular electricity production ability of different microorganisms, but also can be used as indicator for the evaluation of extracellular electricity production ability of different microorganisms. The mixed bacteria in activated sludge are coupled with the trend of MFC to decolorize MO. It is further proved that this method can not only evaluate the extracellular electricity production ability of pure bacteria, but also distinguish the difference of electricity production ability between different mutants of the same microorganism. It can also be used to evaluate the extracellular electricity production ability of the mixed bacteria. In addition, the method can also optimize the carbon source. The experimental conditions such as temperature are used to improve the extracellular electricity production efficiency of microorganisms. Therefore, the high throughput colorimetric evaluation method established in this paper is a simple, convenient, accurate and reliable method with multifunctional utilization.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X703;X172

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1 劉秋月;產(chǎn)電微生物胞內(nèi)電子傳遞途徑選擇及胞外電子釋放能力評估的研究[D];江蘇大學(xué);2017年

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本文編號：1658874