Fungal mycelium is a bio-based raw material that can be sustainably processed into leather-like materials. Until now, increasing the production volume with current methods has been challenging due to mycelium cultivation taking place in a planar two-dimensional form limited in size. VTT's newly-developed production methods make it possible to overcome these size limitations, enabling the continuous manufacturing of mycelium leather sheets by the meter. The approach is applicable to industrial roll-to-roll production.

Conventional leather production has a substantial environmental burden, with a carbon footprint of approximately 130 million tons annually. In addition, it involves vast amounts of land, water, and energy due to mass livestock farming, and processing the leather also has an impact, requiring significant amounts of toxic chemicals.

While so-called "vegan leather," made from synthetic materials, avoids the issues around animal products, they require toxic chemicals to process and take a long time to biodegrade. It, therefore, causes the same problems as any synthetic plastic.

Fungal mycelium is a bio-based raw material that can be sustainably processed into leather-like materials, with the look, feel, and strength of animal leather. It also offers the possibility to be coloured and patterned, and it does not contain any backing or supporting materials. Until now, increasing the production volume with current methods has been challenging due to mycelium cultivation taking place in a planar two-dimensional form limited in size. However, the VTT method now makes it possible to overcome these size limitations.

VTT's patent-pending technology for producing mycelium leather alternative materials is based on growing mycelium in common bioreactors. The benefits of this approach are that liquid fermentation in bioreactors is easily scalable to commercial scales, and similar fermentation technology is already widely used in the food, chemical, and pharma industries. 

The film-making process developed by VTT enables continuous mycelium leather alternative production using VTT's pilot equipment. The benefits of this manufacturing method are consistent quality, competitive production price, and reduced amounts of offcuts.

VTT's new technology enables the continuous manufacturing of mycelium leather at scale, rolling out sheets of the material at a rate of one meter (3.3 ft) per minute. In addition, the approach can be adapted to industrial roll-to-roll production methods. The team is currently exploring first product applications for the material, such as accessories, footwear, and garments.

Last year, a study examined fungus-derived leather alternatives' history, sustainability, manufacturing process, cost, and material properties. It found that Fungi-derived leather is an evolving class of ethically and environmentally responsible materials that are increasingly meeting consumer appealing and functional expectations.