Instead of extracting leather from animal skin or using synthetic fibers, a more environmentally friendly alternative now promises considerable potential: Leather-like materials for clothing, shoes or furniture can also be made from mushrooms. The mushroom leather is not only considered to be biodegradable and ethically harmless, but according to a new study it is also a cheaper alternative to conventional materials.
Leather is a long-lasting and versatile textile, but the production of the tanned animal hide is particularly harmful to the environment: greenhouse gases are produced in livestock farming, the tanning of the hide and the tinting of the material are energy-intensive and processing 1000 kilograms of animal hide, for example, produces around 600 kilograms of waste . Manufacturers of leather items such as shoes or furniture have therefore been looking for alternatives for a long time. But for the synthetic counterpart made of plastics such as polyvinyl chloride (PVC) or polyurethane (PU), petroleum-based raw materials are required, and plastics can also contain chemicals that are harmful to health. The short service life is also considered a disadvantage.
Commitment to the environment
That is why scientists led by Mitchell Jones from the University of Vienna have now investigated the potential of a more sustainable leather alternative: renewable fabric made from mushrooms. In addition to starch molecules, mushrooms also contain biodegradable chitin, which, like the animal structural protein collagen, stabilizes the material. This property has already proven itself in the past: Since chitin has a similar chain-like molecular structure to cellulose, research has already been carried out with the fungal component of mushrooms and co. In the manufacture of paper or construction foams for insulation. It has been used in paper production since the 1950s. Now the textile industry could catch up too, as interest in sustainable textiles is growing.
“This is where leather-like materials obtained from mushrooms come into play, which are CO2-neutral and are usually completely biodegradable at the end of their useful life,” predicts Jones colleague Alexander Bismarck. In order to produce leather fabrics from mushrooms in the most environmentally friendly way possible, the mushrooms can be fed on inexpensive agricultural and forestry by-products such as sawdust. These serve as the basis for the mycelium, i.e. the thread-like structures under the ground that promote the vegetative growth of fungi. The spread of the fungus is also supported by a constant warm temperature, high humidity and carbon dioxide concentration. In addition, the cultivation of the mushroom leather – in contrast to the production of leather from animal origin – causes only a low energy consumption.
The mushroom innovation also has its advantages in the following processing: within a few weeks, the mushroom biomass can be harvested and treated physically and chemically, for example by pressing or drying. “This makes these sheets of fungal biomass look like leather and have comparable material and tactile properties,” says Bismarck. The resulting material is flexible, water-resistant and biodegradable after use. In addition, it can be colored with pigment or mechanically printed with a pattern.
Optimize the idea
According to the researchers, there is still room for improvement in order to be able to market leather made from mushrooms on a large scale: It is still not easy to grow a homogeneous mushroom mass “with uniform growth and constant thickness, color and mechanical properties”. Approaches from paper production such as pressing should be a model here.
The conclusion of the scientists is that mushrooms as raw material for leather substitutes can be a cost-effective, socially and environmentally friendly alternative to cowhide and artificial leather. The researchers write that they are of particular interest to sustainability-conscious consumers and companies as well as to the vegan community. “Significant advances in this technology and the growing number of companies producing the leather alternatives suggest that this new material will play a significant role in the future of ethically and environmentally responsible fabrics”. The first biotech companies are already marketing materials made from mushrooms.
Source: University of Vienna, Article: Nature Sustainability, doi: 10.1038 / s41893-020-00606-1