Why it matters
The environmental ills of clothing production (waste generation, chemical toxicity, energy intensity) are receiving increasing global attention, and the search for sustainable materials is accelerating. The world’s largest apparel brands are developing innovations in circular production methods, in which materials can be closed loop recycled, formed from pre-or post-consumer waste, or safely biodegraded at end-of-life – see PUMA’s cradle to cradle sneakers or Nike’s recycling of waste materials.
Conventional leather is one of fashion’s most ubiquitous materials – but it is fraught with ethical and environmental issues. Waste is typically 15 to 20% for traditional leather, lost when cutting out a garment’s pattern shapes.
Researchers from QUT’s School of Design and scientists from The Edge, State Library of Queensland have been testing growing and using kombucha cellulose as vegan leather, and are exploring ways to prepare, treat and manufacture the leather into garments, shoes, jewellery and bags.
Making the leather
Kombucha is a ferment made by adding a mixed symbiotic culture of bacteria and yeast (known as SCOBY) to sweetened tea. The bacteria acquire nutrients from the yeast, and grow a protective mass of cellulose monofibres, called a pellicle or mother. The mother floats on the surface of the liquid, and will take the shape of its container. After a few weeks, when it has grown to a thickness of about 10mm, it can be harvested, washed (by hand or machine), oiled and air dried.
The material which results is a flexible, leathery sheet that can be cut, stitched, glued or woven. The mother dyes readily while still wet, and takes the shape of whatever supports it as it dries. Complex shapes can be formed by cutting the sheet into strips, and layering them over a form. As they dry, the wet strips fuse into a continuous sheet.
Using the leather
Just like animal-based leathers, leather-like items such as shoes and bags require reinforcing and finishing to increase durability. Shoe styles vary from casual slip-ons to more conceptual designs with handmade wooden heels and soles.
Researchers have experimented with waxing the vegan leather to increase water resistance, laminating it to increase overall strength and wearability, and painting it with acrylics to dramatically change its appearance and improve longevity.
As a naturally sustainable material, kombucha leather has many advantages. Unlike traditional leather, kombucha leather can be grown with zero waste, in tubs shaped as garment pattern pieces.
Can it work on a large scale?
Can kombucha be commercialized at a scale to be a viable vegan alternative to leather? There are two main barriers to overcome: the sweet but pungent aroma (familiar to any home brewer) and water absorption. Like animal-based tanned leathers, kombucha leather is not waterproof. Sealing the leather by rubbing in natural essential oils or beeswax can address both scent and water resistance, although traces of the smell will remain.
These simple treatments make the material showerproof, but like leather, requires more work to make it truly waterproof. Without a sealant, the kombucha could become sticky if worn in the rain. Full water resistance can be achieved if using acrylic or oil based sealers, but then the material is no longer safely biodegradable. As this project aims to minimise waste and be sustainable, our researchers have largely avoided the use of treatments using artificial agents.
However, commercialisation in the mass-market sense is only one avenue to explore. Like many other potentially disruptive technologies, production of kombucha is decentralised, democratised and personal. It gives people the means to make their own leather products on a small-scale. Free and open exchange of knowledge helps parallel communities of tinkerers and makers connect online. This project is only one of many such projects mushrooming globally – from trailblazer Suzanne Lee with her bio-couture jackets, to Sacha Laurin with her runway creations in California, to the ScobyTec start-up in Germany with prototype biker jackets incorporating wearable technology.
Looking to the future, kombucha cellulose may play a role as a mass-market alternative to leather. Other innovations in developing biotextiles include novel biodegradable materials made from waste pineapple leaf fibres (Piñatex™) and fungi, and textile dyes being produced from algae.
For now, kombucha growing provides local, individual makers with sustainable materials – and allows them to tap into the knowledge of a networked global community. This suggests a parallel fashion future in which makers grow their own garments, sharing the SCOBY locally, but ideas and instructions globally.
Make your own leather
Download instructions for making vegan leather and try growing your own.