Rising energy prices and limited resources pose major challenges for the construction industry. At the same time, natural materials are becoming increasingly important in replacing fossil-based insulation materials and enabling sustainable solutions for energy-efficient buildings. This is where the “Mycobuild” research project comes in, which is currently being carried out at the Institute for Circular Economy of Bio:Polymers (ibp) at Hof University of Applied Sciences. The aim is to develop application-ready thermal insulation materials based on fungal meshes and thus establish an industrial manufacturing process.
Conventional insulation materials often consist of synthetic or mineral materials that are produced with high energy consumption and a poor environmental balance. The Hof University of Applied Sciences project takes a different approach: insulating materials made from mushroom mycelium. Project leader Prof. Dr. Robert Honke:
‘Mushroom meshes actually offer numerous advantages: they are compostable,store CO2 and require less energy to produce than conventional fossil-based insulating materials. They can also be shaped flexibly and are industrially scalable.”
Prof. Dr. Robert Honke
The manufacturing process and its challenges
The production of mycelium-based insulating materials, as is currently being tested in Hof, involves several steps. First, a substrate is prepared from regionally available plant residues, such as dry straw, which serves as a breeding ground for the fungi. The mycelium of a selected type of fungus is applied to the substrate, which grows through the material in the desired form within a few days and binds it together to form a solid composite material. The material is then dried and heated to inactivate the fungus. One of the biggest challenges is to allow the fungi to grow under controlled conditions, as they are very sensitive to contamination. Even small amounts of foreign organisms can destroy the entire culture, which is why particular attention must be paid to sterile working conditions and the selection of an optimal substrate. Dr. Katharina Wellmanns, research associate at the ibp at Hof University of Applied Sciences, describes the importance of this step:
‘We have to find the perfect balance: The substrate must provide enough nutrients for the mycelium to grow optimally, but must not contain too many sugars to prevent mold growth.”
Dr. Katharina Wellmanns
Extensive series of tests
Before the material can be used as insulation, however, extensive tests are necessary. The flexibility, moisture absorption and thermal conductivity are already tested in the raw form to ensure that the boards meet the requirements of the construction industry. A key further development of the material is the integration of a mineral top layer by the project partner Johann Bergmann GmbH & Co. KG, which prevents the penetration of moisture and thus minimizes the risk of mould.
The coating is applied in several stages and is also extensively tested to ensure that the material properties are retained. The technology is developing rapidly and it may soon be possible to produce mycelium-based insulation materials that are completely waterproof, virtually eliminating the problem of mold. Dr. Wellmanns is optimistic:
‘Our tests show that the mineral top layer not only protects the material, but also increases its strength. We are working on optimizing the manufacturing process to achieve complete waterproofing.”
Dr. Katharina Wellmanns
The right type of mushroom and its growth conditions
A central aspect of the project is the selection of suitable mushroom species. Native mushrooms have proven to be particularly promising, including the oyster mushroom, honeydew mushroom, fox bolete mushroom and giant mushroom. These mushrooms can grow at room temperature and do not require any additional heating or cooling measures – a decisive advantage for the energy efficiency of production. “Choosing the right type of mushroom is crucial. Some mushrooms grow faster, others form more stable structures. The oyster mushroom in particular has proven to be a robust candidate, as it spreads quickly and forms dense networks,” explains Dr. Wellmanns.
Good mushroom, bad mushroom
However, mushroom cultivation also involves risks. Cultivated mushrooms have to survive against competing microorganisms. If unwanted molds spread, an entire batch can become unusable within a few hours. Careful selection of the nutrient substrate therefore plays a decisive role, as too high a sugar content would encourage the growth of undesirable germs.
Education against reservations
In addition to the technical challenges, there are naturally also reservations on the consumer side. “Many people might be sceptical about an insulation material that is based on fungi, as they fear that this could lead to mould problems in their homes,” admits project manager Prof. Dr. Honke. However, this is precisely why work on the development of the mineral top layer is so intensive. As soon as this is fully developed, the material will be completely insensitive to moisture and, in the best-case scenario, will no longer differ in its properties from conventional insulating materials.
From research to practice
The Mycobuild project is pursuing the medium and long-term goal of transferring the research results into an industrial application. While the Institute for Circular Economy of Bio:Polymers at Hof University of Applied Sciences is responsible for the scientific development and optimization of the material, Johann Bergmann GmbH & Co. KG is the industrial partner responsible for transferring the processes into production. A decisive factor for success is whether production can be scaled up, as the material will only be a real alternative to existing insulating materials once it can be produced in sufficient quantities and at competitive costs.
Funding
The project is supported as part of the DATIpilot funding program of the Federal Ministry of Education and Research (BMBF). The aim of this program is to transfer innovative research approaches into practice and thus strengthen Germany’s innovative power.
Thermal insulation of the future?
Mycobuild is researching a promising approach for a sustainable construction industry. Mushroom meshes as insulation materials could herald a paradigm shift in the industry – with benefits for the environment, the economy and consumers. The project aims to demonstrate industrial feasibility by March 2026 and make a significant contribution to the environmentally friendly construction methods of the future.
To the Institute for Circular Economy of Bio:Polymers (ibp) at Hof University of Applied Sciences:
