Microbial Fuel Cells for Mitigating Greenhouse Gas Emissions from Paddy Fields
2025 Volume 13 Issue 3 Pages 45-56
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2025 Volume 13 Issue 3 Pages 45-56
Paddies contribute significantly to global emissions of greenhouse gases (GHGs), particularly methane (CH4) and nitrous oxide (N2O), and conventional mitigation strategies, such as fertilizer management and water regulation, often fail to address the complex microbial interactions that are the major drivers of these emissions. Thus, microbial fuel cells (MFCs) have been explored as innovative bioelectrochemical technologies for mitigating CH4 and N2O emissions. MFCs mitigate GHG emissions by modifying soil redox potential, fostering microbial competition, and enhancing electron transfer (the oxidation–reduction state of the soil). This systematic literature review, which assesses the findings of 24 relevant studies, is aimed at evaluating the mitigation effects of MFCs on CH4 and N2O emissions from paddy fields. The findings indicate that electron competition consistently suppresses CH4 emission by diverting microbial electron donors from methanogenesis. Conversely, N2O reduction proceeds through a more complex mechanism, relying on the inhibition of the NO3⁻ to NO2⁻ or NO pathway and the activation of the nosZ pathway, which ensures the complete reduction of N2O to N2 without accumulating GHGs as intermediate products, thereby suppressing N2O emission. A follow-up comparative analysis reveals that the mitigation of CH4 emission is more straightforward, whereas that of N2O requires the precise adjustments of the redox–microbial balance. Among the various MFC configurations assessed, that integrating constructed wetlands with MFCs (CW-MFCs) is the most promising owing to its scalability, efficiency, and mitigation effects on CH4 and N2O emissions. Despite these advantages, CW–MFCs still suffer from electrode longevity, energy efficiency, and large-scale implementability issues. Thus, future related studies must explore hybrid bioelectrochemical strategies incorporating CW-MFCs to enhance GHG mitigation and promote sustainable rice farming.
