The mechanism of neutral red-mediated microbial electrosynthesis in Escherichia coli: menaquinone reduction

Journal Article · Tue Sep 01 00:00:00 EDT 2015 · Bioresource Technology

DOI:https://doi.org/10.1016/j.biortech.2015.06.037· OSTI ID:1416694

Harrington, Timothy D.; Tran, Vi N.; Mohamed, Abdelrhman; Renslow, Ryan; Biria, Saeid; Orfe, Lisa; Call, Douglas R.; Beyenal, Haluk

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.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1416694
• Report Number(s): PNNL-SA-110736
• Journal Information: Bioresource Technology, Vol. 192, Issue C; ISSN 0960-8524
• Publisher: Elsevier
• Country of Publication: United States
• Language: English