As much as 50 million metric tons of electronic waste are generated each year across the globe, and this number is only projected to grow, reaching 120 million metric tons by 2050 if current trends continue [1]. But the modest mushroom may be able to help, as researchers show that mushroom skins could be used as a biodegradable alternative to plastic components in computer chips and batteries [2]. 

Computer chips are composed of electronic circuits, which are conductive paths for the flow of electricity, that sit on an insulating and cooling base called a substrate. These substrates are typically made of non-recyclable plastics that are discarded after each use [3]. 

While studying fungus-derived materials, a team of researchers at Johannes Kepler University in Austria discovered that Ganoderma lucidum mushrooms, which grow on decaying wood, form a protective skin around their root-like mycelium. Peeling away and drying the skin produced a flexible and insulating material that resembled a thin sheet of paper and could withstand temperatures of more than 200℃ (390 ℉) [4]. The team then constructed metal circuits on the mushroom skin. Their tests showed that the skin conducted almost as well as standard plastic polymers and could be bent 2,000 times without breakage or loss of electrical resistance [3]. 

The mushroom skin also made for a good battery separator, which is a plastic membrane that is positioned between the positively charged anode and the negatively charged cathode. The mushroom skin was soaked in a conductive electrolyte liquid and placed inside a zinc-carbon battery set up. Two of these mushroom batteries were sufficient to power a humidity sensor at around 1.9 V [5]. For comparison, standard AA and AAA batteries have a nominal voltage of 1.5 V, so these mushroom batteries are quite effective. 

Furthermore, the skin can last for hundreds of years if kept away from moisture, but can decompose in soil or a standard household compost within two weeks, giving the skin the perfect combination of durability and recyclability [4]. While biodegradable electronic substrates have also been made from paper and silk, the process for making these substrates are complex and energy intensive. On the other hand, mushrooms are easily grown on waste wood and cultivating the skins does not require much processing. With such a simple and clean production process, the mushroom-based material holds great potential for the production of large scale, affordable electronics [6]. 

Although a lot of research and experimentation still needs to be done, “myceliotronics” could be a widespread and sustainable alternative to materials used in electronics that don’t need to last for a very long time, such as wearable health monitors and near-field communication (NFC) tags [2]. Moreover, computer chips are found just about everywhere, from cars to home appliances to computers and cell phones. The demand for chips is growing rapidly, and myceliotronics may be able to help meet these needs. Perhaps one day your smart watches and cell phones may even be run by myceliotronics. 

Sources:

[1]https://www.unep.org/news-and-stories/press-release/un-report-time-seize-opportunity-tackle-challenge-e-waste 

[2]https://www.cnn.com/2022/11/15/world/mushroom-skin-electrical-circuits-scn-scli-intl#:~:text=Scientists%20have%20used%20mushrooms%20to%20make%20biodegradable%20computer%20chips&text=The%20skin%20of%20the%20Ganoderma,and%20can%20withstand%20high%20temperatures.&text=Sign%20up%20for%20CNN%27s%20Wonder%20Theory%20science%20newsletter 

[3]https://eandt.theiet.org/content/articles/2022/11/mushroom-skin-could-be-made-into-biodegradable-computer-chips/ 

[4]https://www.newscientist.com/article/2346702-computer-chip-made-using-mushroom-skin-could-be-easily-recycled/

[5]https://www.chemistryworld.com/news/a-recipe-for-biodegradable-mushroom-batteries/4016529.article

[6]https://www.anthropocenemagazine.org/2022/11/mushroom-skins-could-be-the-secret-to-recyclable-electronics/