The mechanism of neutral red-mediated microbial electrosynthesis in Escherichia coli: menaquinone reduction. (September 2015)

• Record Type: Journal Article
• Authors: Harrington, Timothy D.; Tran, Vi N.; Mohamed, Abdelrhman; Renslow, Ryan; Biria, Saeid; Orfe, Lisa; Call, Douglas R.; Beyenal, Haluk
• Is Part Of: Bioresource technology. Volume 192(2015)
• Page Start: 689
• Page End: 695
• Publication Date: 2015-09
• Subjects: Neutral red -- Electron transfer -- Bioelectrochemical system -- Microbial electrosynthesis -- Menaquinone; 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.2015.06.037
• Languages: English
• ISSNs: 0960-8524

Abstract

Highlights: The mechanism of electro-synthesis with neutral red in E. coli was identified. Neutral red reduces menaquinone in the inner membrane. Resulting menaquinol drives anaerobic respiration with multiple electron acceptors. Sans electron acceptor, menaquinol reduces the arcB redox sensor. Reduced arcB causes transcriptional changes that alter metabolite profiles. Abstract: The aim of this work was to elucidate the mechanism of mediated microbial electrosynthesis via neutral red from an electrode to fermenting Escherichia coli cultures in a bioelectrochemical system. Chemical reduction of NAD + by reduced neutral red did not occur as predicted. Instead, neutral red was shown to reduce the menaquinone pool in the inner bacterial membrane. The reduced menaquinone pool altered fermentative metabolite production via the arcB redox-sensing cascade in the absence of terminal electron acceptors. When the acceptors DMSO, fumarate, or nitrate were provided, as many as 19% of the electrons trapped in the reduced acceptors were derived from the electrode. These results demonstrate the mechanism of neutral red-mediated microbial electrosynthesis during fermentation as well as how neutral red enables microbial electrosynthesis of reduced terminal electron acceptors.