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

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

Macroporous and Monolithic Anode Based on Polyaniline Hybridized Three-Dimensional Graphene for High-Performance Microbial Fuel Cells

Microbial fuel cell (MFC) is of great interest as a promising green energy source to harvest electricity from various organic matters. However, low bacterial loading capacity and low extracellular electron transfer efficiency between the bacteria and the anode often limit the practical applications of MFC. In this work, a macroporous and monolithic MFC anode based on polyaniline hybridized three-dimensional (3D) graphene is demonstrated. It outperforms the planar carbon electrode because of its abilities to three-dimensionally interface with bacterial biofilm, facilitate electron transfer, and provide multiplexed and highly conductive pathways. This study adds a new dimension to the MFC anode design as well as to the emerging graphene applications