A 20 L electrochemical continuous stirred-tank reactor for high rate microbial electrosynthesis of methane from CO2

Microbial electrosynthesis of acetate from CO2 under hypersaline conditions

“…BESs have been reported to show higher area-specific ohmic resistance, typically higher than 10 mΩ m 2 because of the low ionic conductivity of microbial compatible catholyte (generally around 10 mS cm −1 ) [ 4 , 26 ]. Considering that the electrolysis of water typically proceeds at the anode, this low apparent resistance of cathode would be expected to greatly affect the energy efficiency of MES, especially at high current densities [ 4 , 8 ]. The voltage used in this research was lower than values used in prior studies but was combined with a higher current density ( Table S1 ), further confirming the decreased energy input required by highly saline MES processes.…”

“…This process could potentially contribute to achieving a sustainable society by storing renewable energy as covalent chemical bonds based on reducing CO 2 [ 5 , 6 ]. MES using whole microorganisms as biocatalysts capable of self-generation and producing long-chain organic chemicals also shows the advantages of lower overpotential, longer operational stability, and milder operational conditions [ 9 , 10 ], compared with systems employing abiotic CO 2 reduction catalysts [ 5 , 7 , 8 ]. Acetate is the most common bioproduct generated by MES, and although low in value and difficult to separate from water, this compound can serve as a precursor for the synthesis of many multi-carbon volatile fatty acid (VFA) compounds of higher economic value, such as caproate, via chain elongation [ 9 ].…”

“…It appears therefore impossible yet to combine relevantly high current densities (i.e., high production rates) and relevantly low cell voltage (i.e., acceptable energy conversion efficiencies) [ 4 ]. Reducing the high ohmic resistance in BESs is therefore crucial to improve MES performance, especially for systems with high current densities or scaled-up structures due to the development trend for MES [ 4 , 6 , 8 ]. A possible solution is to use high-salinity electrolytes, as these reduce the ohmic resistance and thereby the applied voltage needed to drive a certain current density or can increase the current produced under a certain voltage [ 16 ], which would help to improve energy conversion efficiency or production rates in MES.…”

Construction of Cupriavidus necator displayed with a superoxide dismutase for enhanced growth in bioelectrochemical systems

“…Different from sugar or biomass-derived feedstocks, biotransformation of CO 2 faces challenges of inertness of CO 2 molecule and inadequate reducing power from biosystems themselves, leading to slow reaction rate and low conversion e ciency. Recently, renewable electricity-driven microbial electrosynthesis in bioelectrochemical systems (BES) has been emerged as one of the promising technologies for CO 2 biotransformation by overcoming thermodynamic and kinetic barriers of the process (Li et al 2022; Shang et al 2023). Particularly, via BES, CO 2 -derived microbial single cell protein (SCP) has been proposed as a potential alternative to revolutionize the production mode of food and feed in a carbon neutral or negative way (Mishra et al 2020; Yang et al 2022b).…”

Enhanced Anaerobic Digestion Effluent Treatment by an Electrochemical Membrane Bioreactor: Synergistic Roles of Forward Osmosis and Microbial Electrosynthesis

“…Microbial electrosynthesis (MES) has been recently reported as a promising approach for enhancing carbon capture from AD via yielding high-purified biogas. − In our previous work, an electrocatalytic cathode of MES was used to capture CO 2 in the biogas, achieving a high-efficiency biogas upgrading performance for AnOMBR. , In this AnOMBR-MES system, the unwanted CO 2 collected from the bioreactor was flowed into a cathodic chamber and then reduced to formate by a CO 2 reduction reaction (CO 2 RR). However, this ex situ mode was limited in understanding the mechanisms of carbon capture from a bulk solution since many factors cannot be investigated such as the effect of alkali products in the bioreactor and succession in the methanogen community structure .…”