Electrochemically enhanced microbial CO conversion to volatile fatty acids using neutral red as an electron mediator. (January 2018)

• Record Type: Journal Article
• Authors: Im, Chae Ho; Kim, Changman; Song, Young Eun; Oh, Sang-Eun; Jeon, Byong-Hun; Kim, Jung Rae
• Is Part Of: Chemosphere. Volume 191(2018)
• Page Start: 166
• Page End: 173
• Publication Date: 2018-01
• Subjects: Carbon monoxide -- Bioelectrochemical system -- Neutral red -- Electrosynthesis -- Biological CO conversion -- Reducing equivalent; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.10.004
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: Conversion of C1 gas feedstock, including carbon monoxide (CO), into useful platform chemicals has attracted considerable interest in industrial biotechnology. Nevertheless, the low conversion yield and/or growth rate of CO-utilizing microbes make it difficult to develop a C1 gas biorefinery process. The Wood-Ljungdahl pathway which utilize CO is a pathway suffered from insufficient electron supply, in which the conversion can be increased further when an additional electron source like carbohydrate or hydrogen is provided. In this study, electrode-based electron transference using a bioelectrochemical system (BES) was examined to compensate for the insufficient reducing equivalent and increase the production of volatile fatty acids. The BES including neutral red (BES-NR), which facilitated electron transfer between bacteria and electrode, was compared with BES without neutral red and open circuit control. The coulombic efficiency based on the current input to the system and the electrons recovered into VFAs, was significantly higher in BES-NR than the control. These results suggest that the carbon electrode provides a platform to regulate the redox balance for improving the bioconversion of CO, and amending the conventional C1 gas fermentation. Graphical abstract: Image 1 Highlights: Biological CO conversion in a bioelectrochemical system (BES) was examined. Electrode-based electron transference to microbes was enhanced by neutral red (NR). BES-based CO conversion produced acetate, butyrate, propionate, and isovalerate. VFAs production in BES-NR was significantly higher than the control. The coulomb recovery in BES-NR was estimated to be approximately 200%.