Rumen Inoculum Enhances Cathode Performance in Single-Chamber Air-Cathode Microbial Fuel Cells

Area of Science:

• Electrochemistry
• Microbiology
• Environmental Science

Background:

• Microbial fuel cells (MFCs) are explored for sustainable energy generation.
• Optimizing cathode performance is crucial for MFC efficiency.
• Wastewater-derived Geobacter communities are standard for anode inoculum.

Purpose of the Study:

• To investigate the impact of rumen fluid inoculum on MFC performance, specifically cathode biofilm development.
• To compare MFCs inoculated with rumen fluid and wastewater versus wastewater alone.
• To analyze the microbial community structure in response to different inocula.

Main Methods:

• Glucose-fed air-cathode MFC reactors were used.
• Two inoculation strategies were compared: rumen fluid/wastewater vs. wastewater only.
• Power density and soluble chemical oxygen demand (sCOD) removal were measured.
• Pyrosequencing analyzed anodic and cathodic microbial communities.

Main Results:

• MFCs with rumen fluid/wastewater inoculum achieved higher power densities (824.5 mWm⁻²) and sCOD removal (96.1%) than wastewater-only (634.1 mWm⁻², 91.7%).
• Pyrosequencing revealed no significant differences in anode communities but increased Azoarcus and Victivallis in cathodic rumen enrichment.
• Cathode potential differences indicated the cathode as the primary factor for performance variation.

Conclusions:

• Rumen fluid inoculum positively influences cathodic biofilm formation and MFC performance.
• This inoculum improves MFC efficiency without negatively impacting anode microbial communities.
• Rumen fluid represents a promising, underutilized inoculum source for enhancing MFC cathode function.