Mark Megahan
You may think you’re familiar with freaky electric fungus but that’s not the kind you can make a sort of battery from. Empa’s Cellulose and Wood Materials laboratory is still working the bugs out, so you won’t be seeing them on a display rack at Walmart anytime soon. Even so, research undergraduates who drop sensors around all over the forests and fields are going to love them. That’s because this low-watt power source is totally biodegradable.
Fuel from fungus
Humans have been fascinated with fungus for all sorts of reasons. They’re beneficial for food and recreational, too. Some varieties are deadly poison. While you wouldn’t want to serve those to your friends, enemies are a different story, which makes those types useful too.
Environmentally friendly engineering researchers at Empa’s Cellulose and Wood Materials laboratory made a sort of battery from fungi.
Everyone calls it a battery, because it acts like one. The fuel cell is compact and provides power. Just not a whole lot of it. Tinkering with the fungus formula could improve that in the future.
The lab scored a three-year research grant from Gebert Rüf Stiftung. They have a dedicated “Microbials funding program.” Gustav Nyström and his team used the money to develop “a functioning fungal battery.”
While they admit that the fungus doesn’t “produce a whole lot of electricity,” it does supply enough to run “a temperature sensor for several days.” That’s actually a useful application for the technology.
“Such sensors are used in agriculture or in environmental research.” The biggest advantage, the team points out is that “unlike conventional batteries, it is not only completely non-toxic but also biodegradable.”
Print to order
Fungus is alive and acts a lot more like an animal than a plant. “Like all living things, microorganisms convert nutrients into energy. Microbial fuel cells make use of this metabolism and capture part of the energy as electricity.”
Bacteria can perform the same trick. “For the first time, we have combined two types of fungi to create a functioning fuel cell,” says Empa researcher Carolina Reyes.
You need two types of fungi to make it work “The metabolisms of the two species of fungi complement each other.” For the anode side, they use common yeast fungus. That’s because it’s metabolism causes the release of electrons.
They’re collected on a cathode made of white rot spores. That’s because it “produces a special enzyme, allowing the electrons to be captured and conducted out of the cell.”
The fungi are printed into place by mixing them with the conductive ink supplied to the 3D printer. That makes them “an integral part of the cell from the outset.” The preferred nutrient source is simple sugar.
That means the fungus can be printed into shape, coated with beeswax as an aid in handling and shipped dry. In the field, researchers can activate the fuel cells with some sugar water and leave them in place. They’ll disintegrate on their own.
