Scientists have developed a process to produce a particularly sustainable building Material based on mushrooms. A fabric knitted from wool gives a paste-like base material support, which is then overgrown by a mycelium. The result is significantly stronger than other mushroom composite materials, the group rewrites Jane Scott from the University of Newcastle in the journal “Frontiers in Bioengineering and Biotechnology”. However, it does not reach the strength of wood.

Researchers are looking for climate-friendly building materials

For years, researchers have been looking for environmentally and climate-friendly building materials that can be produced without great energy expenditure and have good thermal properties. One of the advantages of mushrooms is that their network – the mycelium – can grow into a shape. This makes it possible, for example, to have furniture parts or building materials without a seam.

Until now, however, the problem with solid formative parts was that fungi did not get enough oxygen and therefore did not grow optimally. Scott and colleagues therefore experimented with a knitted fabric made of merino wool that allows enough air to reach the substrate in which the fungus is supposed to grow.

knitted structures

“The big advantage of knitting technology compared to other textile processes is the possibility of knitting three-dimensional structures and shapes without seams and without waste,” Scott is quoted as saying in a statement from the specialist magazine. The research project also involved designers who created a self-standing structure with parabolic arches that is 1.8 meters high and two meters in diameter. In addition to the knitted form, the object is made possible by a paste that provides nutrients, support structures and water for fungal growth.

This paste consists of beech wood sawdust, paper fiber lumps, paper flour, the polysaccharide xanthan gum, glycerin and more than 75 percent water. It is introduced into the knitted tube with an injection gun and distributed evenly. For the first eight days, this tube was stuck in a plastic structure with the paste to hold the pre-designed shape. Freed from the plastic mold, the fungus of the species Ganoderma lucidum (glossy lacquer polypore) grew vigorously. Before it could form fruiting bodies, it was dried and, with the remains of the paste, formed the mushroom composite material.

Wool ensures an even shape

The researchers tested the properties of the finished substance in various test scenarios. The material resulting from the paste had greater density and better mechanical properties than a mushroom-composite fabric in which the mushroom had only grown on the basis of beech wood sawdust. On the other hand, a mushroom composite material that had grown without a shell showed cracks on drying and lost its mechanical strength. The knitted merino wool apparently ensures that the shrinkage during the drying process is more even and not as massive.

“This is an interesting study, but by no means revolutionary,” says Markus Baumann from the Agency for Renewable Resources in Gülzow-Prüzen. Since the authors of the study see the material produced as a building material, he misses further tests, such as moisture and fire resistance. The main advantage of the mushroom composite material compared to other mushroom composites is its relatively free design during production.

Baumann’s colleague Robert Hardt sees the process presented as a basic idea that can still be optimized in many ways. In addition to the material properties, it is now a question of optimizing the manufacturing process described from an economic point of view.

RND/dpa