Scientists have used fungi to make biodegradable computer chips

By Hafsa Khalil, CNN

Searching for mushrooms doesn’t just mean that mushrooms are on the menu. New research has shown that mushroom skins could be a biodegradable alternative to some plastics used in batteries and computer chips, making them easier to recycle.

Researchers from Johannes Kepler University in Austria were working on flexible and expandable electronics, with a focus on durable materials to replace non-degradable ones, when they made their discovery, published Friday in the journal Science Advances .

“There was a fair bit of serendipity involved,” Martin Kaltenbrunner, head of the university’s soft matter physics division and co-author of the paper, told CNN.

At the time, a member of the team was considering using mushroom derivatives materials that can be used in other fields. This work led to the latest study, which shows how the skin of the fungus Ganoderma lucidum could function as a substitute for the substrate used in electrical circuits.

A substrate is the basis of a circuit that insulates and cools the conductive metals placed on it. As a rule, they are made from non-degradable plastics, which are thrown away after use.

The team, led by Doris Danninger and Roland Pruckner of the university’s Institute for Experimental Physics, found that the fungus – which typically grows on decaying hardwoods in Europe and East Asia – forms a compact protective skin made up of mycelium, a root-like network, to protect its growth medium (the wood).

“They do this in order to protect themselves from the penetration of other fungi or bacteria,” Kaltenbrunner said, explaining that the team was able to harvest this insulating protection by peeling off the skin and dries it out.

According to the research paper, skin is slightly less insulating than plastic, but it has always worked safely and successfully in electrical circuits, with a paper-like thickness and the ability to withstand temperatures above 200° Celsius (392° Fahrenheit), which makes it a good substrate.

Skin has many properties that set it apart from other biodegradable materials, Kaltenbrunner said, “but most importantly, it can simply be grown from waste wood and doesn’t require expensive energy or processing.”

“Our mycelium is kind of in the sweet spot” because it can last a long time if kept dry, but in standard home compost it would fully degrade in two weeks or less, he added.

While the team’s work is currently experimental and far from mass production, they believe that biodegradable skins could be a sustainable alternative material for use in electronics that does not require durable electrical circuits, such than wearable health monitors and near field communication (NFC) tags for electronic devices.

But they also envision wider use if they are able to control mycelium growth to be uniform and reproducible.

There are large amounts of wood waste, like wood shavings from industrial sawing, Kaltenbrunner told CNN, which is a lot of food for fungi.

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