The power of soil microbes: Sustained power production in terrestrial microbial fuel cells under various temperature regimes

•Power was generated from soils incubating at a range of temperatures.•Power output notably lagged in all active terrestrial microbial fuel cells (tMFCs).•tMFCs incubating at 35 °C produced five times the power than those incubating at 5 °C.•Different microbial communities emerged at different temperature profiles.

Recent developments in the field of bioenergy advance the feasibility for energy sources in remote locations with limited infrastructure requirements. Though most research efforts have focused on advancing power output in the marine environment, there is potential to generate power from terrestrial sources. The diversity of native soil biota serves as the inoculum at the electrode surface. In this study, we investigated how microbial fuel cells (MFCs) perform according to a range of temperature regimes, with specific inquiries regarding the level of power output generated at a range of temperatures representative of field conditions and the types of microbes which colonize the electrode surface. Our findings show that there was a notable lag in the increase in power output for all active terrestrial microbial fuel cells (tMFCs) and that the tMFCs incubating at 35 °C produced five times the power density than the tMFCs incubating at 5 °C. As expected, soil microbial activity, as measured through soil respiration, was proportional to both the incubation temperature of the tMFCs and the measured power output. Oppositely, microbial abundance did not increase concurrently with temperature or power output, as demonstrated by archaeal abundance observed to be consistently highest at 25 °C. Amplicon sequencing of the 16S rRNA gene revealed differences in community composition between the cathode and anode, with different communities emerging at different temperature profiles.

Graphical abstractConceptual model of an anode portion of a tMFC, showing theoretical power density as microbes colonize the anode surface and turn into a biofilm.Figure optionsDownload full-size imageDownload as PowerPoint slide