Fungi fuelled batteries

At the heart of this innovation is the microbial fuel cell (MFC), a type of battery that generates electricity by the metabolic processes of microorganisms. Bacteria have usually been the go-to for systems like this. But now, fungi are stepping up as power generators, with Saccharomyces cerevisiae (a yeast) teaming up with Trametes pubescens (a white-rot fungus).

Each fungus plays a specific role: the yeast releases electrons during its metabolic activity at the anode, while the white-rot fungus at the cathode facilitates electron transfer via enzymes. Together, they create a circuit that generates electricity.

3D-printing a revolution

The battery components, including electrodes, are 3D-printed using a cellulose-based ink enriched with fungal cells. This approach ensures that the fungi are integrated directly into the battery’s structure which allows for better nutrient access and metabolic efficiency. Add a bit of water and sugar to activate the dried battery, and the fungi get to work, producing a steady power output.

The result is modest but practical. Just one fungal battery can keep low-energy devices like environmental sensors running for days, and if you link four of them together, it can produce enough power to keep a temperature sensor going nonstop for over 65 hours.

Biodegradable and non-toxic

Unlike traditional batteries, fungal batteries are environmentally friendly. Once their job is done, the fungi can break down the cellulose-based structure from within, leaving no toxic waste behind. This means they are well-suited for use in remote sensing, agriculture, or areas where retrieving spent batteries is challenging.

Although they are promising, fungal batteries face challenges, one of which, as described above, is the amount of output power it can currently transmit, requiring further optimisation of the fungi. More than this, there is also the challenge of printing materials, and cell structure. However, the researchers are on to this, and they aim to explore additional fungal species and refine the 3D-printed designs to increase durability and energy efficiency.

In the long term, these batteries could integrate with smart farming tools, wearable electronics, or even space exploration devices, and their ability to self-decompose makes them particularly attractive for applications where disposal and recycling are a particular cause for concern.

Growing greener energy

Fungal batteries are a great example of how biology and technology can merge to tackle environmental challenges. By tapping into the power of nature, these batteries show us a future of possibilities, where sustainable electronics are truly eco-friendly. Just imagine – a world where food doesn’t just fuel us, but powers our devices too!