Development of a circular sustainable culturing process for natural leather-like materials based on fungal myceli

Textile and Leather are among the industries with the highest environmental impact (besides the meat and oil/gas industries). Bolt Threads ( has developed a natural material called MYLO from fungal mycelium which is a sustainable and cost competitive alternative to real and synthetic leather. The mycelium that is the basis of MYLO is grown on a substrate (MYSUB®) based on a side stream (sawdust) supplemented with nutrients. After harvest of the mycelium the foamy material (MYFOAM®) is processed into MYLO.

To optimize production of the increasing volumes for MYLO, further automation and (lower cost) substrates that are both sustainable and locally available are required. For implementation of the process abroad, also the use of local mushroom species will be important. Production of MYLO generates its own side streams. The spent substrate after harvest of MYFOAM® and side streams from the MYLO process are potentially valuable natural resources and finding applications would contribute to further circularity of the industry, as well as contribute to the chances of success of a vegan leather alternative (better economic viability) to replace more polluting textiles.

In this project we want to develop a roadmap to an economically scalable circular process to produce natural leather-like materials based on fungal mycelium, that is suitable for use of local available side streams as raw materials, and that valorizes and re-uses occurring side streams.

  1. Screen the ability of different fungi for the formation of MYFOAM® on various types of biobased side streams as substrates.
  2. Characterize the properties of MYFOAM® from different fungi grown on different substrates.
  3. Explore applications for the sustainable re-use of the spent substrate and MYLO side streams.

After 2 years, at the end of this feasibility study project, a route to a technically and economically viable process of MYLO based will be mapped. Then a follow-up development project will start. As the choices made will affect further research and development as well as the partners in a follow-up project the choice was made for a duration of 2 years in this project and then continue most likely with new partners in a development project.