Mycelium, the underground network of fibres below mushroom caps, grown in liquid-filled tanks has been processed into a leather-like fabric through a pulp-based route that allows continuous sheet production. The researchers harvested the resulting pulp, mixed it with additives to improve flexibility and strength, and formed it into dried sheets from which they sewed a prototype handbag.
- The roller system used in scale-up testing has yielded sheets about 8 inches (20 centimetres) wide and 26 feet (8 metres) long from a single continuous run.
- The paper 'Your next handbag could start with mushrooms' was recently published in ACS Applied Bio Materials.
THE METHOD: The study method submerged Trichoderma reesei, a fungus, in nutrient-rich liquid inside tanks like those used to brew beer, where rather than producing a sheet the fungus grew into a thick, pulp-like mass. Manuel Arias-Barrantes, Géza Szilvay and their colleagues at VTT Technical Research Centre of Finland harvested the pulp, washed it, mixed in sorbitol and cellulose, spread the mixture into thin sheets and dried it, creating a nonwoven fabric, meaning one made from fibres bonded without weaving, with a leather-like finish.
- Most mycelium materials are made by letting fungi grow across trays until thread-like fibres knit themselves into a solid sheet, an approach that cannot be used for mass production.
- Sorbitol, a naturally occurring sugar alcohol frequently added to foods and cosmetics, and cellulose, the main structural component of plant cell walls, were added to improve flexibility and strength.
- Funding came from Business Finland through the Research to Business programme, the Research Council of Finland through the Center of Excellence in Life-Inspired Hybrid Materials, and VTT Technical Research Centre of Finland.
WHAT HELD UP: The rolled-out mycelium material has matched the pull-resistance of traditional leather in laboratory tests. The material has broken down in water within 28 days, has completely disintegrated under industrial composting conditions in about six weeks, and still needs improved tear resistance before mycelium-based products reach consumers.
- The pulp-based approach has given researchers control over colour, texture and cotton layering, with tensile strength, resistance to being pulled apart, reaching leather-comparable levels.
- Continuous production has yielded sheets about 8 inches wide and 26 feet long, establishing the scale at which the prototype handbag was made.
- The researchers said the manufacturing process is promising because it uses equipment already common in the biotechnology and printing industries.
WHAT THEY SAID
Many people are looking for alternatives to fossil fuel-based and animal-derived materials, yet scalable alternatives remain limited. Our work has solved one significant bottleneck, enabling large-scale production of affordable mycelium-based fabrics.
— Manuel Arias-Barrantes (Co-author)
Researcher
VTT Technical Research Centre of Finland
