Activation Enhancement of Citric Acid Cycle to Promote Bioelectrocatalytic Activity of <i>arcA</i> Knockout <i>Escherichia coli</i> Toward High-Performance Microbial Fuel Cell

Abstract

The bioelectrocatalysis in microbial fuel cells (MFCs) relies on both electrochemistry and metabolism of microbes. We discovered that under MFC microaerobic condition, an <i>arcA</i> knockout mutant Escherichia coli (arcA^–) shows enhanced activation of the citric acid cycle (TCA cycle) for glycerol oxidation, as indicated by the increased key enzymes’ activity in the TCA cycle. Meanwhile, a diffusive electron mediator (hydroxyl quinone derivative) is excreted by the genetically engineered arcA^–, resulting in a much higher power density than its parental strain toward glycerol oxidation. This work demonstrates that metabolic engineering is a feasible approach to construct efficient bioelectrocatalysts for high-performance MFCs