3D-Printed Methane-Producing Electrodes for Microbial Fuel Cells Developed Using Biogel Ink Containing Live Methanogens and White Charcoal |
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Authors: | Masaki Umetsu Yosuke Watanabe Masato Ueno Tatsuya Kobayashi Hidemitsu Furukawa Chika Tada |
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Affiliation: | 1. Graduate School of Environmental Studies, Tohoku University, 6-6-20 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8579 Japan;2. Graduate School of Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata, 992-8510 Japan;3. Graduate School of Agricultural Science, Tohoku University, 232–3 Yomogida, Naruko-onsen, Osaki, Miyagi, 989-6711 Japan |
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Abstract: | Methanogens are used as catalysts for cathodes in microbial fuel cells, to reduce CO2 to CH4. However, the attachment of microbes to the electrodes via culturing is time-consuming, and inadequate biofilm formation can lead to lesser surface area coverage, resulting in reduced methane formation. This study aims to improve the production efficiency and performance of methanogen cathodes developed using 3D printing of bioink containing live methanogens. A progressive cavity pump is used for the 3D gel-printing of methanogens and micro-sized white charcoal particles into the desired structure. Despite the absence of anaerobic conditions during printing, the 3D-printed cathodes with higher concentrations of microbial inoculum in the bioink produce more methane gas. Even with an unconcentrated inoculum, the methanogens multiply 800-fold during incubation, resulting in increased methane gas production. The predominant methanogens in the electrodes included the hydrogenotrophic Methanobacterium spp. Therefore, the technique used in this study can be used to successfully develop 3D-printed biocathodes catalyzed by methanogenic microbes with verifiable practical applicability. This study is the first to report the growth of methanogens and their methanogenic activity in 3D-printed cathodes. |
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Keywords: | 3D printing charcoal methane methanogens microbial fuel cell progressive cavity pump |
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