A study published in ACS Sustainable Chemistry & Engineering by researchers at the Swiss Federal Laboratories for Materials Science and Technology (Empa) introduces a novel 3D-printed biobattery utilizing cellulose and fungi. This environmentally friendly device, known technically as a microbial fuel cell (MFC), incorporates yeast and white-rot fungus mixed with cellulose hydrogel to create electronically conductive inks for use as electrodes.
The biobattery, which combines these fungal inks, beeswax, and a cellulose proton exchange membrane, aims to provide a biodegradable energy source suitable for powering agricultural or environmental sensors in remote areas. Importantly, its design addresses the growing concern of electronic waste, as the components are fully biodegradable.
The MFC leverages the metabolic processes of the selected microorganisms. Brewer’s yeast (Saccharomyces cerevisiae) generates electrons from nutrient breakdown, while the white-rot fungus (Trametes pubescens) utilizes these electrons to reduce oxygen, facilitating the generation of electricity.
According to Dr. Carolina Reyes, the study’s lead author, the use of fungi in MFCs presents a unique approach compared to the more common bacterial designs. Each electrode in the biobattery is crafted from a cellulose-based hydrogel enhanced with carbon black and graphite nanoflakes to improve conductivity.
In trials, the biobattery produced between 300 and 600 mV for several days and could successfully power a small temperature sensor for 65 hours when four units were connected in parallel. A notable benefit of this system is its ability to store fungi in a dehydrated state, allowing for easy transport and reactivation with water and nutrients.
The research team plans to explore various fungal species to enhance the power and longevity of future models. Potential applications include energy sources for sensors monitoring environmental conditions in agricultural and forest settings, as well as low-power devices in more specialized fields, including space exploration.
