Microbial Electrochemical Systems for Sustainable Energy Production

Microbial electrochemical systems harness the ability of specialised microorganisms to exchange electrons with electrodes, enabling the direct conversion of organic substrates or light energy into electrical power or value-added chemicals. Core configurations include microbial fuel cells (MFCs), which generate electricity through anodic oxidation of waste streams; microbial electrolysis cells (MECs), which produce hydrogen or other reduced compounds under a modest external bias; and microbial electrosynthesis platforms, which drive reductive biosynthesis by feeding electrons from cathodes into microbial metabolism. Advances in electrode materials, reactor design and biofilm engineering have progressively improved energy recovery, reaction rates and system stability. The integration of photoactive organisms in biophotovoltaic arrangements further extends the spectrum of electron-transfer pathways. Together, these developments promise low-carbon processes for wastewater treatment, biofuel generation and carbon-neutral chemical manufacture, offering scalable solutions aligned with circular-economy and decarbonisation goals.

Research from Nature Portfolio

A mechanistic investigation into electroactive biofilms has revealed that conductive pili form an integrated network, linking individual cells and matrix-associated cytochromes to the underlying anode. This study demonstrated that pili-deficient mutants develop thin biofilms with limited current generation beyond a critical thickness, whereas wild-type constructs maintain high conductivity over extended distances. The findings clarify the complementary roles of pili and cytochromes in long-range electron transport and guide future biofilm engineering strategies to maximise power density in anode environments.

Microbial Electrochemical Systems for Sustainable Energy Production publication trend

The graph below shows the total number of articles in microbial electrochemical systems for sustainable energy production across all publications each year (not limited to Nature Index journals).

Technical terms

Microbial fuel cell: A device in which microorganisms oxidise organic substrates at an anode to generate electric current.

Microbial electrolysis cell: A system that uses an external voltage to drive microbial catalysis of reductive reactions, typically to produce hydrogen.

Extracellular electron transfer: The process by which microbes exchange electrons with solid surfaces or electrodes outside the cell envelope.

Biofilm: A structured microbial community attached to an inert surface and embedded in a self-produced matrix.

c-type cytochrome: A haem-containing protein that mediates electron flow within microbial respiratory chains and biofilms.

Pili: Proteinaceous filaments extending from the cell surface that can conduct electrons and facilitate cell-to-electrode connectivity.

References

1. Biophotovoltaics: oxygenic photosynthetic organisms in the world of bioelectrochemical systems. Energy & Environmental Science (2015).
2. Extracellular electron transfer from cathode to microbes: application for biofuel production. Biotechnology for Biofuels and Bioproducts (2016).
3. Iron based catalysts from novel low-cost organic precursors for enhanced oxygen reduction reaction in neutral media microbial fuel cells. Energy & Environmental Science (2016).
4. Electricigens in the anode of microbial fuel cells: pure cultures versus mixed communities. Microbial Cell Factories (2019).
5. Mechanistic stratification in electroactive biofilms of Geobacter sulfurreducens mediated by pilus nanowires. Nature Communications (2016).