Electro-fermentation driven detoxification of furfural to methane

Anaerobic digestion of pretreated lignocellulosic hydrolysates valorizes biowaste into biomethane; however, the inherent inhibitory by-products severely suppress microbial metabolism. Electro-fermentation offers a promising strategy to simultaneously address the challenges of furfural detoxification and carbon recovery. Herein, we report the effect of externally applied voltages (0.0-1.6 V) on furfural detoxification and methanogenesis. An applied voltage of 1.2 V achieved the highest methane yield of 37.50 mL with complete furfural removal, outperforming both the open-circuit condition and higher voltages. This superior performance was attributed to the formation of dense electroactive biofilms and the upregulation of functional genes (e.g., hmf, fwd/fmd), which promoted the electrochemical reduction of furfural to furan derivatives and subsequent microbial ring-opening into acetate/CO₂ at the biotic-abiotic interface. This study provides new design guidelines for converting toxic by-products in hydrolysates into biomethane via electro-fermentation.