A mushroom’s underground network could soon be doing the job of plastic wrap. Researchers at the University of Maine have developed a new packaging material that combines fungal mycelium with wood-derived cellulose nanofibrils (CNFs) to deliver a water- and oil-resistant barrier that can biodegrade after use.
The team, led by Caitlin Howell (associate professor of bioengineering), uses mycelium (the root-like filament network beneath mushrooms) as a naturally water-resistant “top layer”, while CNFs contribute grease and oil barrier performance. The result is a thin coating that can be applied onto fiber-based substrates such as paper, or formed into a free-standing film: slightly fuzzy on one side, and plastic-like to the touch on the other.
In practice, the approach mimics how fungi behave in the wild: give mycelium something to grow on and it will spread, threading itself through gaps to create a continuous skin. In Howell’s lab, the fungus is grown ahead of time, then blended with extra nutrients (including a malt extract broth) and mixed with CNFs. Blending keeps the hyphae, the branching filaments that make up fungi, small at the start, so they regrow evenly. CNFs play a double role, acting as both a scaffold/food source for the fungus and a barrier layer in their own right.
Once grown and dried, the coating measures roughly 20–25 microns, around a quarter of the thickness of a human hair. UMaine researchers have spent years working on CNF materials for their biodegradability and resistance to oils; adding the mycelium layer brings the missing piece: robust water resistance.
For this project, the lab selected Trametes versicolor (the “turkey tail” mushroom), a wood-decaying species that can readily feed on wood-based CNFs. Beyond performance, the food-safety argument is central: “We already eat fungi, so we know that they’re going to be safe for us long-term,” Howell said.
Speed is the other headline. Conventional mycelium materials can take weeks to grow to usable thicknesses; the UMaine team reports cutting that timeline to about three days. Next, they want to scale: adapting the method to roll-to-roll equipment could take production from square centimeters per hour to square meters per hour, pushing the concept closer to commercialization and lowering costs further.
The timing is no coincidence. Packaging is under pressure to move beyond “plastic-lined everything”; not only because of waste, but also because the chemistry of plastics is getting harder to ignore. A recent PlastChem inventory maps more than 16,000 chemicals used in plastics, with over a quarter flagged as hazardous chemicals of concern, while global plastic waste leakage into aquatic ecosystems is estimated at 19–23 million tonnes each year.
If a fungus-grown barrier can meet the realities of food packaging (humidity swings, grease, and high-speed processing) it could offer fiber-based packs and coatings a new route: compostable by design, without sacrificing the performance that made plastics ubiquitous in the first place.
