定電位馴養電活性菌應用於微流道微生物燃料電池快篩系統

Abstract

微生物燃料電池為一種再生能源，電池中具有電化學活性之微生物，能氧化廢水中的營養物質，達到處理污染物同時又產生電能之效果，因而此技術逐漸受到關注。本研究施加恆電位(200 mV、0 mV、−200 mV、−400 mV)於陽極進行電化學活性菌之馴養，待系統穩定後進行次世代定序與電化學活性(極化曲線、功率密度曲線、循環伏安法與電化學阻抗分析)的分析。分析完畢後，進行單一菌株分離之篩選，將馴養之混菌分離成為單一純菌，並將其置於微流道系統中進行單一菌株產電能力之評估。 結果顯示，施加−200 mV恆電位馴養之生物陽極具有較佳表現，該系統產生最大功率密度187.3 mW m-2，並於電化學阻抗分析中觀測出電極極化阻抗由9206降至105.8 ohms、總內阻為337 ohms，並由循環伏安法觀測出明顯之氧化還原波峰。 本研究所純化出的單一菌落普遍具有生物修復性，其中五株菌株Acinetobacter brisouii、Arcobacter lacus、Chryseobacterium cucumeris、Pseudomonas citronellolis、Pseudomonas delhiensis為尚未被評估產電能力之菌株，於本研究所建立之快篩系統觀測出具相當產電潛力。最後期許未來能將此系統加以精進並廣泛應用，以利後人更加了解單一微生物之電化學機制。

Microbial fuel cell (MFC) is one kind of green energy harvesting techniques. Although many exoelectrogens as essential anode-respiring bacteria have been proved to be able to produce electricity and treat pollutants simultaneously, there are still many potential exoelectrogens unclear and warrant the need for further research. In this study, mixed-culture exoelectrogens were steadily cultivated under constant potential in the dual-chamber microbial fuel cells with microbial community analyses and electrochemical performance of biofilms being evaluated by utilizing 16S rRNA gene high throughput sequencing and power density curve, polarization curve, electrochemical impedance spectroscopy and cyclic voltammetry. After isolating diverse pure bacterial strains from the anode biofilms, we established a fast-screening system using the microfluidic laminar flow MFC (MLFMFC). By inoculating the isolated strains in the anode of MLFMFC and measuring its open circuit and closed circuit voltages, we can rapidly and efficiently identify the electroactive bacteria among these isolates. Results showed the bioanode domesticated under a constant potential of −200 mV had the better performance with maximum power density of 187.3 mW m-2. Acinetobacter brisouii, Arcobacter lacus, Chryseobacterium cucumeris, Pseudomonas citronellolis, and Pseudomonas delhiensis were isolated and first proved to be capable of producing electricity in this study by our fast-screening systems. In conclusion, this fast-screening system was successfully established and verified and it is expected to be widely utilized in the future to better isolate effective exoelectrogens.