Developing reactors for electrifying bio-methanation: a perspective from bio-electrochemistry

Abstract

Next-generation electro-bioreactors will require development of novel reactor-tailored components to improve reactor productivity while maintaining high energy efficiency and biocompatible reactor conditions.

Electrochemistry‐Based CO2 Removal Technologies

“…Selecting microbes, cathode materials, and operating conditions is key in development and design of sustainable and large-scale microbial electrosynthesis systems. [51] Microbial electrosynthesis is the utilization of cathodederived electrons for CO 2 reduction, which can occur in two different ways: 1) by a direct transfer of electrons from the cathode to a microbe or 2) indirectly by microbial use of electrochemically-generated hydrogen in the cathode compartment. The latter platform has proven most efficient for many reasons: 1) only a limited number of microbial species are able to accept electrons directly from a cathode, 2) it is a great engineering challenge to develop and maintain a high metabol- ic rate in biofilm on a cathode 3) the intrinsic propensity of cathodes to produce H 2 at the low potentials applied is minimal, and 4) H 2 -consumption in an anoxic bioreactor is wellunderstood providing easier operation of such reactors.…”

“…The presence of oxygen at the cathode can create a toxic environment for the microbes, resulting in a significant reduction of the faradaic efficiency. [51] Microbial electrosynthesis, when coupled to metabolicallydependent microorganisms using renewable electricity is a highly favorable platform for production of multi-carbon compounds from CO 2 . [52] This includes e-fuels and chemical precursors such as of methane, acetate, ethanol, caproate, butyrate, and butanol, to name a few compounds.…”

“…Developments within genetic engineering and systems biology are expected to further expand the spectrum of applicable microbes. Selecting microbes, cathode materials, and operating conditions is key in development and design of sustainable and large‐scale microbial electrosynthesis systems [51] …”

“…A selective membrane separates the cathode and anode chambers; thereby, preventing mixing of the reaction components. The presence of oxygen at the cathode can create a toxic environment for the microbes, resulting in a significant reduction of the faradaic efficiency [51] …”

Identification of 2-Hydroxyacyl-CoA Synthases with High Acyloin Condensation Activity for Orthogonal One-Carbon Bioconversion

“…Advances in electrochemical reduction of CO 2 powered by rapid deployment of carbon-free electricity have spurred an interest in the use of one-carbon (C1) compounds as attractive feedstocks for sustainable biomanufacturing. While electrochemistry can offer an efficient route to convert CO 2 to C1 compounds such as carbon monoxide, formic acid (formate), formaldehyde, methanol, and methane, biochemistry has a great potential in creating carbon–carbon (C–C) bonds from C1 compounds to produce value-added multicarbon products. Since industrial platform organisms such as Escherichia coli or Saccharomyces cerevisiae do not metabolize C1 compounds, C1-based biomanufacturing requires either the conversion of these microbial platforms into synthetic C1-trophs or the engineering of native C1-trophs to produce desired products .…”