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.
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http://dx.doi.org/10.1016/j.biortech.2015.06.037 | DOI Listing |
Biotechnol Bioeng
December 2024
Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark.
Acetogenic bacteria play an important role in various biotechnological processes, because of their chemolithoautotrophic metabolism converting carbon dioxide with molecular hydrogen (H) as electron donor into acetate. As the main factor limiting acetogenesis is often H, insights into the H consumption kinetics of acetogens are required to assess their potential in biotechnological processes. In this study, initial H consumption rates at a range of different initial H concentrations were measured for three different acetogens.
View Article and Find Full Text PDFJ Ind Microbiol Biotechnol
December 2024
Department of Biology, Washington University in St. Louis, St. Louis, MO, USA.
In this review, we focus on how purple non sulfur bacteria (PNSB) can be leveraged for sustainable bioproduction to support the circular economy (CE). We discuss the state of the field with respect to the use of purple bacteria for energy production, their role in wastewater treatment, as a fertilizer, and as a chassis for bioplastic production. We explore their ability to serve as single cell protein and production platforms for fine chemicals from waste materials.
View Article and Find Full Text PDFFoods
November 2024
College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China.
Utilizing (), this study constructed a dual-chamber microbial electrosynthesis system, based on microbial electrolysis cells, that was capable of producing lycopene. Cultivation within the electrosynthesis chamber yielded a lycopene concentration of 282.3722 mg/L when the optical density (OD) reached 0.
View Article and Find Full Text PDFTrends Biotechnol
December 2024
Institute of Technical Microbiology, Hamburg University of Technology (TUHH), Kasernenstraße 12 (F), 21073 Hamburg, Germany. Electronic address:
Autotrophic microbial electrosynthesis (MES) processes are mainly based on organisms that rely on carbon dioxide (CO) as an electron acceptor and typically have low biomass yields. However, there are few data on the process and efficiencies of oxic MES (OMES). In this study, we used the knallgas bacterium Kyrpidia spormannii to investigate biomass formation and energy efficiency of cathode-dependent growth.
View Article and Find Full Text PDFEng Microbiol
September 2024
State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China.
The consumption of non-renewable fossil fuels has directly contributed to a dramatic rise in global carbon dioxide (CO) emissions, posing an ongoing threat to the ecological security of the Earth. Microbial electrosynthesis (MES) is an innovative energy regeneration strategy that offers a gentle and efficient approach to converting CO into high-value products. The cathode chamber is a vital component of an MES system and its internal factors play crucial roles in improving the performance of the MES system.
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