Emerging Technologies for Biobutanol Production via Syngas Fermentation

Abstract

Biobutanol offers significant advantages over ethanol as an advanced biofuel, but its large-scale production via syngas fermentation faces critical challenges including low product titers, carbon inefficiency, and microbial toxicity. To address these limitations and evaluate technological progress, this review summarizes recent progress in syngas-based butanol synthesis, focusing on microbial catalysts, metabolic pathways, and process optimization strategies. Particular emphasis is placed on acetogenic bacteria and the role of the Wood–Ljungdahl pathway in carbon fixation and energy conservation. Key factors affecting product distribution, including gas composition, reactor configuration, pH, temperature, and trace elements, are discussed in detail. Furthermore, recent developments in enhancement approaches such as metabolic engineering, co-cultivation systems, and electro-fermentation are critically examined. While several pilot and demonstration-scale ethanol production systems have been established, large-scale biobutanol production via syngas fermentation remains limited due to challenges related to low titers, carbon inefficiency, and product toxicity. Advancing this technology will require a multidisciplinary effort integrating microbial physiology, systems engineering, and process intensification. This review aims to provide a foundation for future research and technological development in the field of gas-to-liquid biofuel production.