Conductively functionalized E. coli cells for enhancement of biological hydrogen production with electrical...

Biological hydrogen production is an attractive route toward sustainable fuel generation, but its efficiency remains limited by poor electron transfer across the bacterial envelope. Here, we construct a conductive biohybrid electrode (CC/PPy@E. coli) by decorating Escherichia coli (E. coli) with Fe^3 +-initiated polypyrrole (PPy) and immobilizing hybrid cells on the carbon cloth (CC) surface. Spectroscopic and microscopic characterizations confirm the formation of a PPy layer on the bacterial surface and the stable attachment of the hybrid to the conductive scaffold. Under optimized conditions, CC/PPy@E. coli produces 2.0 times hydrogen within 24 h than the output of CC/E. coli under the same electrical stimulation and 1.7 times that of the same biohybrid electrode without electrical stimulation. The biohybrid electrode further maintains a clear performance advantage during repeated operation and retains relatively high activity at seawater. Metabolite profiling further suggests that electrical stimulation redistributes intracellular carbon flux around pyruvate, favoring the formate-linked branch associated with hydrogen evolution while suppressing the competing lactate pathway. These results identify conductive polymer engineering of the biotic-abiotic interface as an effective strategy for improving electrical stimulated microbial hydrogen production.