Status, scale-up and microbial genes perspective in microbial electrosynthesis for multi-step carbon dioxide upgrading to value-added products

Increased atmospheric carbon dioxide (CO₂) emissions in the atmosphere due to excessive usage of fossil fuels, rapid industrial development and human growth have raised a global interest in the greenhouse effect. CO₂ conversion is important not just because it is a greenhouse gas that causes a variety of climate consequences, but also because it is the most abundant source of valuable organic chemicals. Upgrading CO₂ into valuable chemicals and materials offers a pathway toward net-zero or even carbon-negative production of fuels, pharmaceuticals, alcohols, plastics, etc. However, current CO₂ conversion technologies have the problems of high operational costs, high energy consumption, limited to a few-carbon products, and a risk of secondary pollutants. Microbial electrosynthesis (MES) is a novel microbial electrochemical technology that integrates the metabolic activities or genetic behaviour of microorganisms on electrodes to convert CO₂ into organics with electrical energy input. Recent developments in electrode and reactor design, synthetic biology-based strain engineering, and genetic engineering have enhanced the production rates and selectivity of MES. This review explores the transformative potential and recent progress of MES with CO₂ upgrading strategies, aiming to identify the determinants of the process and its future research directions.It also highlights the current challenges of MES related to upscaling, long-term stability, selecting optimal microbial strains, achieving net-negative carbon emissions, and other operational limitations that need to be addressed for commercial viability.