Electronic waste is one of the world’s fastest-growing waste streams. Millions of smartphones, computers and electronic toys reach the end of their lives every year. Most of these products contain printed circuit boards (PCBs) made from glass fibre-reinforced epoxy resin. Because these fossil-based materials are difficult to recycle and do not biodegrade, they create major end-of-life challenges.

Researchers at TU Bergakademie Freiberg have developed a compostable alternative using the mycelium of Aspergillus niger, a fungus commonly used in industrial citric acid production. Instead of discarding this industrial by-product, the researchers convert it into a bio-based substrate for electronic circuits.

Turning Fungal Mycelium into Circuit Boards

The research team transforms the fungal biomass into a plastic-like material through moulding and air drying. This process produces rigid plates that are approximately 5 mm thick. The material has a density of 1.23 g/cm³, which is comparable to conventional PCBs.

The researchers produced working circuit board prototypes by applying conductive patterns directly onto the fungal substrate. They used both direct ink writing and conventional etching techniques before manually soldering electronic components onto the boards.

According to doctoral researcher Nina Oehlsen, laboratory tests showed promising mechanical strength and good heat resistance. The electrical performance does not yet match that of conventional PCBs. However, the material already performs well enough for prototypes and low-frequency applications. Possible uses include environmental sensors, consumer products and electronic toys.

The team still needs to improve the material before it can replace conventional PCBs. Future work will focus on reducing water absorption and testing the material against standards such as IPC-A-600 and DIN EN 60249-1.

Reducing Electronic Waste

The Global E-waste Monitor estimates that the world will generate 82 million tonnes of electronic waste by 2030. The researchers developed the prototype, called AnimatPCB, to help reduce this growing waste stream.

The fungal substrate is fully biodegradable and can be composted after use. Designers can also recover and reuse the mounted electronic components. This approach reduces waste and supports a more circular product lifecycle.

Junior Professor Linus Stegbauer, who specialises in biogenic technical materials, explained that the project converts an industrial waste product into a functional engineering material. The process does not require additional fossil-based raw materials. Compared with conventional PCBs, the fungal material has a CO₂ footprint up to 56% lower. It can also dissolve safely in water at the end of its service life.

Supporting Circular Electronics

The researchers see the project as an important step towards circular electronics. Professor Simon Glöser-Chahoud, who analysed the material’s environmental impact, said the study demonstrates that electronic components can combine functionality with lower environmental impacts throughout their life cycle.

Although the technology still requires further development, the research shows how industrial biotechnology residues can become valuable engineering materials. In the future, these bio-based substrates could help designers create electronic products with a lower environmental footprint and improved end-of-life options.

Source: TU Bergakademie Freiberg
Photos: TU Bergakademie Freiberg / A. Hiekel