Enhanced electron transfer on microbial electrosynthesis biocathode by polypyrrole-coated acetogens. (August 2020)

• Record Type: Journal Article
• Authors: Luo, Haiping; Qi, Jiaxin; Zhou, Meizhou; Liu, Guangli; Lu, Yaobin; Zhang, Renduo; Zeng, Cuiping
• Is Part Of: Bioresource technology. Volume 309(2020)
• Publication Date: 2020-08
• Subjects: Microbial electrosynthesis system -- Biocathode -- Polypyrrole-coated acetogens -- Extracellular electron transfer; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2020.123322
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: PPy coating increased acetate production rate of biocathode by 3–6 times. PPy-coated biocathode have 30–60% lower charge transfer resistance than uncoated. 3. Quinone loop and NADH to ubiquinone were involved in PPy-coated biocathode. 4. C-type cytochromes played a less important role on biocathode EET. Abstract: Extracellular electron transfer (EET) is a significant pathway to transport electrons between bacteria and electrode in microbial electrosynthesis systems (MESs). To enhance EET in the MES, a high-conductivity polymer, polypyrrole (PPy), was coated on the surface of mixed culture acetogens in situ and the PPy-coated bacteria were inoculated on the cathode of MES. The charge transfer resistance of PPy-coated biocathode was 33%–70% of that with PPy-uncoated. Acetate production rate and Faradic efficiency in PPy-coated biocathodes increased by 3 to 6 times. After 960 h operation, Acetobacterium, Desulfovibrio, and Acinetobacter dominate the community on the coated and uncoated biocathode. Quinone loop and NADH dehydrogenase to ubiquinone were involved in electron transfer pathway of biocathode and stimulated by PPy coating. Low-level expression of C-type cytochromes on biocathode indicated its less important role in inward EET. The study provided useful information for applications of high-conductivity chemicals in microbial electrosynthesis.