Successive bioanode regenerations to maintain efficient current production from biowaste

Area of Science:

• Environmental Science
• Microbiology
• Electrochemistry

Background:

• Long-term operation of efficient bioanodes using waste-derived organics is a challenge for bioelectrochemical systems (BES) in waste valorization.
• Developing sustainable methods to maintain bioanode performance is critical for practical applications.

Purpose of the Study:

• To describe a simple procedure for maintaining highly efficient bioanodes fed with biowaste.
• To assess the impact of anode renewal on bioanode performance and stability.

Main Methods:

• Utilized three fed-batch reactors with varying biowaste loading rates.
• Implemented a bioanode renewal procedure to restore performance.
• Monitored electroactive biofilm dynamics using 16S rRNA-gene amplicon sequencing.

Main Results:

• Achieved current densities up to 14.8 A/m², with over 40% electron recovery from biowaste.
• Observed an initial decline in coulombic efficiency (22–31%), which was recovered after anode renewal.
• Maintained stable high performance (approx. 40% coulombic efficiency) for at least 3 weeks post-renewal.
• Identified Geobacter sulfurreducens and various Bacteroidetes as dominant microbial groups, suggesting community adaptation.

Conclusions:

• A simple anode renewal procedure can effectively maintain high performance of bioanodes in BES for biowaste valorization.
• The microbial community, dominated by Geobacter and Bacteroidetes, adapts to biowaste degradation, contributing to system stability.