Current status of fermentation and electroactive fermentation technologies for biofuel production: A systematic review

The sustainable production of biofuels remains a central challenge in the transition to low-carbon energy systems. Fermentative processes have been extensively developed for ethanol, butanol, methane, and hydrogen, yet their efficiency is constrained by redox imbalances which cause metabolic regulation bottlenecks. Electroactive Fermentative Technologies (EAFT), including electrofermentation and other bioelectrochemical systems, offer bioelectrochemical control of microbial metabolism to improve yields, product selectivity and energy efficiency. This systematic review synthesizes current progress in traditional fermentation and Electroactive Fermentative Technologies, focusing on performance indicators, techno-economic implications, and environmental impacts. Findings were harmonized through unit standardization for quantitative outcomes and thematic synthesis for qualitative evidence. The analysis highlights that while EAFT can enhance redox balance, increase substrate selectivity, and couple microbial metabolism with renewable electricity, it remains at a low technology readiness level and faces operational, economic, and scale-up barriers. Common challenges across both conventional and electrofermentative approaches include feedstock variability, inefficient downstream recovery, and the lack of integrated techno-economic and life-cycle assessments. Future research should prioritize systems biology and metabolic engineering for pathway optimization, hybrid configurations combining EAFT with established processes, and demonstration at pilot and commercial scale. Although EAFT is not yet a mature substitute for traditional fermentation, its ability to couple microbial metabolism with bioelectrochemical control positions it as a transformative platform for next-generation biofuel and biorefinery applications. • This review maps recent advances in fermentation and EAFT across four biofuels. • EAFT improves redox control, boosts yields, and enhances carbon-use efficiency. • Scale-up is constrained by mass transfer, metabolic limits, and reactor design. • Environmental and techno-economic evidence remains limited across biofuel systems. • Future progress needs integrated biorefineries plus better strains and reactors.