Insight of synergy between biosurfactant-producing Klebsiella sp. HN02 and magnetic biochar mediators enables hydrophobic para-xylene-fed high-performance microbial fuel cells.

This study developed a microbial fuel cell (MFC) integrated with magnetic biochar (Fe3O4@BCFPs) and the biosurfactant-producing strain Klebsiella sp. HN02 (HN02) to realize synergistic degradation of hydrophobic para-xylene (PX) and power generation. Using 5 g/L Fe3O4@BCFPs, the system achieved rapid PX removal and enhanced power density by 1.94-fold to 0.53 ± 0.01 W/m3. The Fe3O4@BCFPs also promoted electron transfer and stimulated biosurfactant secretion from HN02, improving the bioavailability of hydrophobic PX. This synergy enhanced dehydrogenase activity, maintained 83.0 % live cells in biofilms, and increased the emulsification index by 83.3 %, thereby establishing a highly active bioelectrochemical interface. Key intermediates (4-methylbenzyl alcohol and p-toluic acid) revealed a PX degradation pathway involving side-chain oxidation and benzene ring cleavage, accompanied by reduced toxicity. This study demonstrates a scalable strategy for treating industrial volatile organic compounds with simultaneous electricity generation by coupling the adsorption and capture of PX with efficient electroactive biodegradation.