Treatment of 2,4-di-tert-butylphenol-containing wastewater with an anaerobic baffle reactor coupled microbial fuel cell (ABR-MFC) system: performance, microbial communities, and metabolic functions

• ABR-MFC reactor efficiently treated low concentrations of 2,4-DTBP. • Power generation diminished as 2,4-DTBP concentration increased. • Proteobacteria and Nitrospirota decreased with increasing 2,4-DTBP. • 2,4-DTBP adversely impacted nitrogen metabolism of ABR-MFC reactor. 2,4-Di- tert -butylphenol (2,4-DTBP), a recalcitrant phenolic pollutant, poses a certain ecological risks due to its widespread industrial use. This study investigated the response of an anaerobic baffle reactor-microbial fuel cell (ABR-MFC) system to 2,4-DTBP in wastewater. Results showed that the ABR-MFC achieved > 99 % removal of 2,4-DTBP at low concentrations (1–2 mg/L). However, increasing 2,4-DTBP to 5 mg/L caused functional declines: ammonia–nitrogen removal reduced to 82.88 %, and power generation efficiency decreased (compartment1 resistance surged from 1282.2 Ω to 8068.4 Ω). Microbial analysis revealed that elevated 2,4-DTBP shifted community structure (increased Bacteroidota, decreased Proteobacteria/Nitrospirota) and enriched potential degraders ( Leptolinea and Syntrophorhabdus ). Functional predictions linked 2,4-DTBP stress to inhibited nitrogen cycling, with reduced abundance of nitrification ( amoA ) and denitrification genes ( nosZ , nirK/S ), suggesting incomplete denitrification. Path modeling further confirmed that 2,4-DTBP impaired nitrogen metabolism and bioelectrochemical stability despite enhancing microbial diversity. These findings provide critical insights for optimizing bioelectrochemical systems treating 2,4-DTBP contaminant.