The team isolated F. terrae from paddy soil and found that it performs bidirectional extracellular electron transfer, moving electrons across the cell boundary in both directions. While most organisms rely on internal chemical reactions for energy, some microbes interact electrically with their surroundings, exchanging electrons with minerals or electrodes to survive in oxygen limited conditions and influence large scale biogeochemical cycles.
In controlled laboratory systems, F. terrae directly transferred electrons to iron bearing minerals, reducing iron compounds without the need for soluble chemical shuttles. The bacterium reached iron reduction efficiencies above sixty percent, indicating a flexible respiratory metabolism that can adapt to different electron acceptors. Electrochemical measurements showed that the microbe donates electrons to solid electrodes and also accepts electrons from them, forming stable biofilms that maintain long term electrical contact with surfaces.
The study highlights that this microorganism can tap electrical energy and direct it into carbon metabolism. According to the authors, its metabolic flexibility suggests a biological platform for coupling renewable electricity with carbon capture and conversion. The work points to a microbial strategy that may be harnessed in devices designed to turn waste carbon into valuable products.
The researchers observed that F. terrae uses electricity to power carbon fixation when supplied with electrons from an electrode and carbon dioxide as the only carbon source. Under these conditions, the bacterium converted carbon dioxide into acetate through the Wood Ljungdahl pathway, a highly efficient microbial route for carbon fixation. The experimental system produced acetate at concentrations above 11 millimolar, demonstrating effective storage of electrical energy in chemical form.
Genomic and biochemical analyses indicate that c type cytochromes help mediate the electrical interactions by acting as molecular conduits for electron transfer across the cell envelope. The bacterium also appears to employ conductive pili that act like microscopic wires, improving electron flow between cells and external materials such as minerals or electrodes. These structures support the formation of electroactive biofilms that can participate in long range electron transfer.
The discovery broadens current understanding of sulfate reducing bacteria, which are already known for their roles in sulfur cycling, metal corrosion, and environmental cleanup. Only a small set of microbes had previously been recognized as capable of fully bidirectional extracellular electron transfer. The newly described mechanism suggests that sulfate reducing bacteria may have more extensive roles in natural redox processes and engineered bioelectrochemical systems than previously thought.
Microbial electrosynthesis technologies use microorganisms to convert electricity and carbon dioxide into fuels or platform chemicals and are drawing attention as tools for lowering greenhouse gas emissions. By demonstrating efficient acetate production driven directly by electrical energy, F. terrae offers a new biological resource for building cleaner chemical manufacturing systems. Its abilities could support reactors that run on renewable power while capturing and transforming carbon.
The authors note that further work is needed to improve performance, evaluate stability over long operating periods, and clarify how electroactive microbes behave in complex natural and engineered environments. Even so, the study underlines the potential of electroactive microorganisms as living bridges that link renewable energy systems with carbon recycling processes. As efforts to limit climate change intensify, such approaches may contribute to technologies that turn waste carbon into feedstocks for a low carbon economy.
Research Report: Bidirectional extracellular electron transfer and electroautotrophic metabolism in Fundidesulfovibrio terrae
Related Links
Shenyang Agricultural University
Powering The World in the 21st Century at Energy-Daily.com
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
