Researchers at the University of Fribourg have shown how the chemistry of bacteria that do not require oxygen changes when they are exposed to different external conditions. These bacteria can be used in rechargeable organic batteries.

Some extreme bacteria can thrive without oxygen. Chemists in the research group led by Professors Katharina M. Fromm and Bernd Giese have exposed these bacteria to different metal ions in different concentrations and investigated how the bacteria adapt chemically to this external stress.

Some bacteria that do not use oxygen for breathing regulate their energy balance by exchanging electrons with metal atoms in the outside world. Metal ions (in minerals or in dissolved form) are therefore just as important for these bacteria as oxygen is for us. The researchers were able to measure how the bacteria adapt to external conditions within a few minutes to survive. They produce components called cytochromes to transport the electrons through the cell membrane to the outside.

Bacteria for batteries

The number of electrons produced was also measured with these experiments: one bacterium produces around 500,000 electrons per second. For this reason such bacteria can be used in batteries. The study results contain important findings for the development of new sustainable and rechargeable organic batteries. In addition, thanks to their properties, these bacteria can be used as little helpers for breaking down pollutants and treating wastewater. 

Article: Kinetic and Mechanism of Mineral Respiration: How Iron-Hemes Synchronize Electron Transfer Rates, M. Karamash, M. Füeg, V. Chabert, L. Simond, E. Madivoli, N. Hérault, C. Salgueiro, J. Dantas, B. Giese, K. M. Fromm, in Angewandte Chemie International Edition, DOI: 10.1002/anie.201914873