Improving microbial electrosynthesis with biochar electrodes in production of CO2 derived biochemicals and biofuels within circular economy systems

Abstract

The urgent need to mitigate greenhouse gas emissions and transition to a circular economy has driven the exploration of bioelectrochemical technologies including microbial electrosynthesis (MES). MES offers a promising pathway for CO₂ conversion into valuable biochemicals and biofuels; however, its scalability is limited by challenges such as high cathode costs, inefficient electron transfer, and poor microbial attachment. Biochar, derived from waste biomass, presents a sustainable and cost-effective alternative to conventional carbon-based electrodes due to its high porosity, tunable surface chemistry, and low associated production costs. However, the optimisation of biochar properties for MES applications, including its electrochemical performance and stability, has not been definitively analysed. This paper summarises the recent advancements in biochar electrodes for MES, focusing on material characteristics, modification strategies, and their impact on overall system efficiency. Furthermore, the potential of integrating MES with existing biogas facilities to enhance carbon recovery, and reduce resource consumption is discussed. Overcoming current challenges in consistent biochar electrode production, and its integration with existing infrastructure is essential for advancing MES technology in real world applications. The findings suggest that waste-derived biochar electrodes have the potential to improve MES scalability and economic viability, supporting the development of sustainable biochemicals within circular economy systems.