Bioelectrochemical systems and engineered living materials: a tutorial on carbon capture and sustainable energy

Bioelectrochemical systems (BESs) and engineered living materials (ELMs) are revolutionizing sustainable energy and carbon management by addressing thermodynamic and kinetic barriers in energy conversion and carbon capture. However, misconceptions about the terminology along with a lack of comprehensive environmental footprint and lifecycle assessments still impact the BESs. In this context, this Tutorial Review highlights the distinct roles of bio-batteries and biofuel cells (BFCs) and addresses the substrate-specific effects on electron transfer (ET), carbon flux, and metabolic byproducts. In yeast, the glucose substrate facilitates rapid, high-flux ET suitable for immediate applications, while fructose supports prolonged ET activity, demonstrating flexibility in carbon capture and energy conversion, as the core of the BES. Thermodynamic analysis reveals the energy potential of extracellular polymeric substances (EPSs), storing energy, while kinetic analyses feature the influence of enzymatic efficiency and mass transport limitations. Additionally, ethanol production integrates energy efficiency with environmental sustainability. By overcoming thermodynamic, kinetic, and scalability challenges, BESs and ELMs emerge as transformative tools advancing carbon neutrality, circular economy, and green energy innovation. Strategic research directions, including synthetic biology and scalable materials, are proposed to enhance the modularity and accelerate the transition to commercial viability.