[Long-term performance of microbial fuel cell using manure as substrate].

Area of Science:

• * Environmental Science and Engineering
• * Renewable Energy Technologies
• * Microbiology and Biotechnology

Background:

• * Commercialization of microbial fuel cells (MFCs) hinges on long-term performance and stability.
• * Dairy manure presents a viable substrate for MFC energy recovery.

Purpose of the Study:

• * To evaluate the long-term operational stability and performance of an MFC using dairy manure.
• * To analyze key electrochemical parameters and microbial community dynamics over an extended period.

Main Methods:

• * Long-term performance testing of an MFC over 171 days with dairy manure as substrate.
• * Electrochemical measurements including polarization curves, open circuit voltage, and internal resistance.
• * Phylogenetic analysis of anodic biofilm microbial communities.

Main Results:

• * Sustained electricity recovery from dairy manure with an average power density of 6.77 Wm⁻³ ± 2.11 Wm⁻³.
• * On day 70, MFC exhibited an open circuit voltage of 0.874 V, internal resistance of 22.1 Ω, and maximum power density of 14.1 Wm⁻³.
• * Total Chemical Oxygen Demand (TCOD) removal decreased over time, while Coulombic Efficiency (CE) reached 17.5% ± 3.3% between days 121-150.
• * Dominant microbial communities included Proteobacteria (45%), Bacteroidetes (22%), Firmicutes (17%), and Actinobacteria (11%), with electricity- and cellulose-degrading genera like Clostridium and Cellulomonas being abundant.

Conclusions:

• * MFCs demonstrate long-term stability and efficiency in electricity generation from dairy manure.
• * The microbial community composition, particularly the prevalence of electrogenic and cellulolytic bacteria, supports sustained MFC performance.
• * Findings support the potential of MFC technology for sustainable energy recovery from agricultural waste.