3D printing meets biotechnology: fungi battery generates sustainable electricity

Researchers at the Swiss materials research institute Empa have developed an innovative microbial fuel cell that uses fungi as an energy source. Made from biodegradable materials, this battery could revolutionize applications in agriculture or environmental research. The technology offers great potential, particularly in remote regions where conventional power supply is difficult. After use, the battery decomposes by itself – a solution that combines environmental friendliness and functionality.

The basis of the mushroom battery is a combination of two types of fungi. The yeast fungus on the anode side produces electrons through its metabolism, while the white rot fungus Trametes versicolor on the cathode produces an enzyme that captures and transfers these electrons. This biological interaction replaces conventional electrochemical processes. By using 3D printing, the researchers were able to adapt the electrode structure in such a way that the microorganisms are optimally supplied with the necessary nutrients. The ink used for printing consists of cellulose, which is not only biodegradable but is also used by the fungi as a food source. “For the first time, we have combined two types of fungi to create a functioning fuel cell,” says Empa researcher Carolina Reyes.

The main challenge in developing the battery lay in the combination of materials. The ink had to be both electrically conductive and viable for the fungi without damaging their delicate cell structures during the printing process.

“It is challenging enough to find a material in which the fungi grow well,” says Gustav Nyström, Head of the Cellulose and Wood Materials Laboratory. “But the ink also has to be easy to extrude without killing the fungal cells – and of course it has to be electrically conductive and biodegradable.”

The energy yield of the mushroom battery is currently sufficient to operate temperature sensors for several days, for example. “The mushroom batteries can be stored in a dried state and activated at the place of use simply by adding water and nutrients,” says Reyes.

In the long term, however, the team is aiming to increase efficiency and expand the range of mushrooms. “Mushrooms are still under-researched and under-utilized, especially in the field of materials science,” agree Reyes and Nyström.