Germany researchers turn citric acid waste into compostable circuit boards

TU Bergakademie Freiberg on July 10 presented compostable circuit boards made from Aspergillus niger mycelium, a byproduct of industrial citric acid production. The prototype turns fermentation residue into a plastic-like electronics substrate.

The material is processed by molding and air-drying, then used for functional prototype circuit boards. Junior professor Linus Stegbauer showed a sample of the fungal mycelium powder after it had been dried and ground in the lab. The feedstock starts as production waste rather than a dedicated crop.

The Freiberg project uses biomass left over from the citric acid industry, where Aspergillus niger is already part of the production chain. That residue is a basis for biodegradable printed circuit boards, a route that could replace epoxy-based laminates if the material can clear the technical bar for electronics manufacturing.

The boards can be composted after use without leaving conventional electronic waste.

For now, the result remains a functional prototype, not a commercial panel. The mycelium-based material still has to meet the electrical, thermal and mechanical demands of real circuit-board production at scale, using a process simple enough to compete with established epoxy systems.