(476b) Electro-Biodiesel Empowered By Co-Design of Microorganism and Electrocatalysis

Developing an efficient and sustainable method for fuel production is essential for reducing reliance on fossil fuels and advancing humanity's sustainable development goals. Proposed solutions like biofuels or electro-fuels seek to address this issue, but encounter constraints in either efficiency or the carbon chain length of their products, hindering their efforts to decarbonize critical sectors like long-range heavy-duty vehicle fuels. We have integrated electrocatalytic CO₂ reduction reaction (CO₂RR) for biocompatible C2+ production with microbial fermentation to generate lipids, establishing a novel route for CO₂-to-electro-biodiesel production. For the first time, we unveiled metabolic constraints in microbial C2 utilization through simulations and metabolomics. This systems biology analysis guided the further design of synthetic biology approaches to attain reductant balance, boost ATP production, enhance lipid conversion efficiency, and increase lipid yield. Additionally, we identified optimal ratios of ethanol and acetate to achieve co-substrate synergy for lipid production. Moreover, we designed a bimetallic catalyst tailored to produce the desired C2 product profile, facilitating an optimal lipid conversion. The co-design of microorganism and catalyst has enabled the electro-biodiesel system to achieve a solar-energy-to-lipid conversion efficiency of 4.6%. This platform combines efficient CO₂RR that can be powered by renewable energy with lipid biosynthesis using microbial cell factories, potentially reducing land use by 48-fold compared to current biodiesel methods and potentially leading to negative carbon emissions in contrast to traditional gasoline.