Selective Enrichment Establishes a Stable Performing Community for Microbial Electrosynthesis of Acetate from CO2

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• 作者：Sunil A. Patil ; Jan B. A. Arends ; Inka Vanwonterghem ; Jarne van Meerbergen ; Kun Guo ; Gene W. Tyson ; Korneel Rabaey
• 刊名：Environmental Science & Technology
• 出版年：2015
• 出版时间：July 21, 2015
• 年：2015
• 卷：49
• 期：14
• 页码：8833-8843
• 全文大小：524K
• ISSN：1520-5851

文摘

The advent of renewable energy conversion systems exacerbates the existing issue of intermittent excess power. Microbial electrosynthesis can use this power to capture CO₂ and produce multicarbon compounds as a form of energy storage. As catalysts, microbial populations can be used, provided side reactions such as methanogenesis are avoided. Here a simple but effective approach is presented based on enrichment of a robust microbial community via several culture transfers with H₂:CO₂ conditions. This culture produced acetate at a concentration of 1.29 卤 0.15 g L^鈥? (maximum up to 1.5 g L^鈥?; 25 mM) from CO₂ at a fixed current of 鈭? Am^鈥? in fed-batch bioelectrochemical reactors at high N₂:CO₂ flow rates. Continuous supply of reducing equivalents enabled acetate production at a rate of 19 卤 2 gm^鈥?d^鈥? (projected cathode area) in several independent experiments. This is a considerably high rate compared with other unmodified carbon-based cathodes. 58 卤 5% of the electrons was recovered in acetate, whereas 30 卤 10% of the electrons was recovered in H₂ as a secondary product. The bioproduction was most likely H₂ based; however, electrochemical, confocal microscopy, and community analyses of the cathodes suggested the possible involvement of the cathodic biofilm. Together, the enrichment approach and galvanostatic operation enabled instant start-up of the electrosynthesis process and reproducible acetate production profiles.