Peer-reviewed study is the first to show a single fungal species both remediating resin-contaminated wood waste and forming a viable insulation material from it.

Engineers at the University of Bath have grown a common woodland fungus on waste oriented strand board (OSB) to produce a bio-based insulation material that matches the thermal performance of conventional products, with carbon emissions more than 10 times lower. The peer-reviewed study, published in Scientific Reports, is the first to show a single fungus both breaking down a resin-contaminated engineered wood product and forming a usable insulation composite from it.

OSB, an engineered wood panel made from compressed flakes bonded with synthetic resins, is widely used in walls, flooring and roof decking, but the resins that give it strength also make it one of construction’s more problematic waste streams. As a result, it’s commonly incinerated or landfilled, where it can release toxic fumes and greenhouse gases including methane.

Currently, wood waste accounts for 20 to 30 per cent of construction and demolition waste and roughly 10 per cent of total UK landfill volume, and treated products such as OSB have no established recycling route.

The Bath researchers chipped waste OSB off-cuts, soaked them and inoculated them with Trametes versicolor - a white-rot fungus commonly known as turkey tail and found throughout UK woodlands. Over five days, the fungus colonised the substrate and its mycelium - a network of root-like filaments - bound the material into a solid composite. The specimens were then oven-dried to inactivate the fungus, leaving an inert bio-based material.

The resins in the OSB did not prevent colonisation and thermal testing showed the resulting material insulated as well as mineral wool, expanded polystyrene (EPS) and extruded polystyrene (XPS). The researcher’s life cycle assessment found its carbon footprint was a fraction of petrochemical-based insulation and roughly a third of rockwool’s when compared on equivalent insulating performance.

“One of the biggest challenges in construction is what happens to materials at the end of their life,” said Joni Wildman, lead author and researcher in the university’s Department of Architecture and Civil Engineering. “This is the first time we’ve shown the fungus doing two jobs at once - creating a sustainable insulation material and transforming challenging, and potentially harmful, waste into something valuable.”

Most of the production emissions came from electricity used in drying and incubation, and the researchers identified drying as the single biggest contributor - accounting for a third of the total carbon footprint. More efficient drying methods and lower-temperature sterilisation could bring the figure down further at industrial scale.

The study used clean manufacturing off-cuts rather than demolition waste, which may contain paints, coatings or fasteners needing additional handling. Sourcing from concentrated streams such as factory off-cuts is likely to be more practical in the near term than mixed demolition waste.

However, fungal colonisation takes several days rather than the minutes needed for conventional foam production, which the team note is a constraint for scaling up. Further work will look at how the material performs over time in different moisture conditions, and whether other difficult waste streams - including plastics - can be processed the same way.

Dr Andrew Shea, project supervisor, added: “This is an exciting step towards using biology to rethink how we make and use materials in building construction.”

Source: resourcemedia.eco