Bio-cathodic treatment of toluene and nutrients in an integrated bubble column-microbial fuel cell: Electricity generation and microbial community shift.

Abstract

An integrated bubble column reactor-microbial fuel cell (BCR-MFC) was developed for simultaneous aerobic toluene vapor biodegradation, nitrification, heterotrophic denitrification, and electricity generation. The BCR-MFC was tested under various inlet loading rates (ILRs) of toluene to the bio-cathode chamber. The maximum elimination capacity (EC max ) reached 248 g m -3 h -1 at an ILR of 456 g m -3 h -1 . Optimal performance occurred at an ILR of 306 g m -3 h -1 , yielding an EC of 208 g m -3 h -1 and a voltage output of 522 mV based on the integrated efficiency parameter (ε). The highest power density (4.8 W m -3 ) was obtained at the lowest ILR (70 ± 6 g m -3 h -1 ). At an ILR of 316 ± 30 g m -3 h -1 , NH₄ + -N decreased from 1.3 g L -1 to 0.134 g L -1 , and NOₓ - -N from 1.3 g L -1 to 0.239 g L -1 . Microbial community analysis revealed increased abundance of toluene-degrading bacteria, heterotrophic denitrifiers, and nitrifiers, including Pseudomonas, Paracoccus, Zoogloea, and Bacillus. These results highlight the BCR-MFC ability to couple efficient toluene degradation with nitrogen compound removal while producing bioelectricity, facilitated by the coexistence of essential microbial species in the bio-cathode chamber.

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Identifiers

DOI

10.1016/j.bioelechem.2025.109148

PubMed

41138672

Journal

Bioelectrochemistry (Amsterdam, Netherlands)

Year

2025