[Application of Microbial Fuel Cells in Reducing Methane Emission from Rice Paddy]

We aimed to study whether the methane emission from rice paddy with straw return can be alleviated in microbial fuel cells (MFCs). In our study, the soil mixed with 0. 5% ( mass fraction) rice straw was packed into MFCs reactors, then flooded with excess of sterilized water and transplanted with rice seedlings followed by the operation of MFCs. The MFCs were operated for 98 days covering five stages of seeding, tillering, mid-season aeration, rice filling, and ripening. The voltage data were recorded continuously and in real time during the MFCs operation and the methane emitted was collected once a week using the static chamber method and the methane emission flux was determined by gas chromatography. The results showed that the MFCs current increased and reached the peak value in the seeding and tillering stages and the operation of MFCs significantly reduced the accumulative methane emission in these two stages. The possible reason could be that the electrogens competed with methanogens for organic substrates. The height, the above and below ground biomass, and the productivity of rice plants were not significantly affected by the 98-day operation of MFCs. Our study provides a potential green and sustainable technology for the reduction of CH, emission from rice paddy fields.