Mushrooms show promise as memory chips for future computers

Fungal networks could provide a promising alternative to tiny metal devices used to process and store digital memories and other computer data, according to a new study.

Mushrooms have long been recognized for their extreme resilience and unique properties. Their innate abilities make them perfect specimens for bioelectronics, an emerging field that, for next-generation computing, could contribute to the development of exciting new materials.

As an example, researchers at Ohio State University recently discovered that common edible mushrooms, such as shiitake mushrooms, can be grown and trained to act as organic memristors, a type of data processor capable of remembering past electrical states.

Their results showed that these shiitake-based devices not only demonstrated reproducible memory effects similar to those of solid-state chips, but could also be used to create other types of inexpensive, environmentally friendly, brain-inspired computer components.

“Being able to develop microchips that mimic real neuronal activity means you don’t need a lot of power while idle or when the machine is not in use,” said John LaRocco, lead author of the study and a psychiatric research scientist at Ohio State’s College of Medicine. “This is something that can be a huge potential IT and economic benefit.”

Fungal electronics is not a new concept, but it has become an ideal candidate for developing sustainable computing systems, LaRocco said. This is because they minimize electrical waste by being biodegradable and cheaper to manufacture than conventional memristors and semiconductors, which often require expensive rare earth minerals and large amounts of power from data centers.

“Mycelium as a computational substrate has already been explored in less intuitive configurations, but our work attempts to push one of these memristive systems to its limits,” he said.

The study was recently published in the journal PLOS One.

To explore the capabilities of the new memristors, the researchers grew samples of shiitake and button mushrooms. Once ripe, they were dehydrated to ensure their long-term viability, connected to special electronic circuits, and then electrocuted at different voltages and frequencies.

“We would connect electrical wires and probes to different points on the mushrooms, because distinct parts of them have different electrical properties,” LaRocco said. “Depending on voltage and connectivity, we observed different performance.”

After two months, the team discovered that when used as RAM – the computer memory that stores data – their mushroom memristor was able to switch between electrical states at up to 5,850 signals per second, with around 90% accuracy. However, performance decreased as the frequency of electrical voltages increased, but just like a real brain, this could be corrected by connecting more mushrooms to the circuit.

Overall, their research shows how surprisingly easy it is to program and curate mushrooms to behave in unexpected and useful ways, said Qudsia Tahmina, study co-author and associate professor of electrical and computer engineering at Ohio State. Additionally, it’s an example of how technology can advance when it builds on the natural world.

“Society is increasingly aware of the need to protect our environment and ensure that it is preserved for future generations,” Tahmina said. “So this could be one of the driving factors behind new bio-responsible ideas like these.”

Building on the flexibility offered by fungi also suggests that there are opportunities to expand fungal computing, Tahmina said. For example, larger mushroom systems may be useful in edge computing and aerospace exploration; the smallest ones to improve the performance of autonomous systems and portable devices.

Organic memristors are still in their early stages, but future work could optimize the production process by improving cultivation techniques and miniaturizing the devices, as viable fungal memristors would need to be much smaller than what the researchers achieved in this work.

“All you need to start exploring mushrooms and computing could be as small as a compost pile and a few homemade electronics, or as large as a grow factory with pre-made templates,” LaRocco said. “All are viable with the resources we currently have.”