How to biofabricate leather; lessons from the lab

Laura Muth
June 21st 2019

Leather is one of the oldest and most versatile materials in the world. It’s a supple, tough, relatively strong and durable material and it’s relatively impermeable, yet breathable. Having existed in some form or another since the dawn of mankind, leather is used for a wide range of products—varying from furniture, clothes and accessories, to car upholstery.

The history of leather is long and has brought us many different processing methods, yet the implementation of a circular approach within production is still a long way off. We therefore need visionaries to come up with valid alternatives in order to move towards a more sustainable approach.

Labs like Waag’s TextileLab Amsterdam and the Open WetLab give designers access to technology and living matter, in order to create alternative materials while looking at material development from a circular point of view. I am one of these designers.

How leather is made

For the production of leather, theoretically, any animal skin can be used. It’s most often made from cows, calves, sheep, goats and pigs. The production of leather comes with many problems, as it’s made from animal hide treated with chemicals. In effect, the tannery wastewater used to make the leather with, contains large amounts of chemicals and pollutants (such as chromium salts, lime mud, sulphides, acids, lead, cyanide, and formaldehyde). These not only infect the people working in the tanneries, they also accumulate the groundwater.

Over the course of the 19th century, more and more alternatives for leather were explored, of which ‘leatherette’ is currently used most. Leatherette is a synthetic material designed specifically to mimic leather, it’s typically made from natural or synthetic cloth fibers coated in PVC or polyurethane and contains no animal by-products.

This led me to wonder, whether this plastic-coated material is a valid alternative in a time where we urgently need to move towards a circular approach. Because why not develop a plastic- and cruelty free material that less affects our planet as a whole?

How leather could be made

At Waag’s TextileLab Amsterdam I dove into the history of leather and the different working methods of producing the material, but looked even closer into leather alternatives and their manufacturing processes.

During the research I worked in the labs at the intersection of design, technology and biology, growing my own materials, wondering whether we would succeed in creating alternative leathers, cancelling out the existing problems that leather creates. Instead of working in a traditional studio, I suddenly worked in a lab, combining the expertise of various disciplines in order to explore new perspectives on the design of products in relation to its materials.

Focusing on alternative leathers from kombucha- and mycelium-leather, I worked towards a small collection of 3D-embossed purses and backpacks, inspired by the insect kingdom; especially the pillbug.

Leather from fermented tea

The first material I started working with was kombucha, or, the so-called ‘scoby’ (a thick, rubbery and cloudy mass that aids the fermentation process of kombucha).

In western culture, many people will perceive kombucha as a new drink, but drinking it has already been done for centuries to purify the body and strengthen the immune system.

Note: this part may get a bit technical, so bear with me.

Kombucha starts out as a sugary tea, which is then fermented with the help of the scoby; the bacteria in the scoby break down the tea's sugars and convert them into alcohol. The kombucha culture can be bought in special tea shops, bio-stores and online.

All too often, you’ll hear about the so-called kombucha mushroom or tea mushroom. However, the kombucha mushroom is not an independent fungus, but rather a symbiosis of various yeasts, single-celled fungi, or more precisely, the Ascomycota and Acetic acid bacteria.

The yeasts multiply in kombucha exclusively vegetatively through bud or cleavage. It forms a whitish, gelatinous layer on the tea surface, whereby new layers grow on top of each other. The color may vary from light grey to pink to dark brown, depending on the tea that is used.

The research consisted of treating the kombucha with several substances such as glycerine, beeswax and alcohol, in order to make it durable and water repellent, as this is still a challenge of this material. To prevent the material from growing mold, conventional vinegar is often used.

In comparison to animal leather, the kombucha grows really fast, it doesn’t need much space and nutrition besides a hint of sugar. But most importantly, it can be grown in different shapes! Scroll down for recipes.

Leather from mushrooms

Another very promising material is Mycelium. Mycelium is the vegetative part of a fungus or a fungal-like bacterial colony, consisting of a mass of branched filamentous hyphae.

Depending on the strain of mycelium is used, they have a lot of properties. Some are water absorbent, others flame retardant and dielectric materials. I used mycelium from Oyster-mushroom and Schizophrenia on the surface of nutrient liquid. Mycelium can be grown on agricultural waste and can be applied in many fields; from an alternative to polystyrene and plastic packaging to furniture, bricks and leather-like materials from mycelium.

However, keep in mind that mycelium grows relatively slow; for a piece of 50x70 centimeters, this takes more than two months to grow.

This is only the beginning

In my research I mainly focused on the process of growing the alternative leather myself, and less on the application until now. As you can see, there are a lot of interesting and promising alternatives for making leather. But to be fair, these are still not ready to meet the characteristics of animal skin. More research is needed, but alternative materials and their possible applications are definitely worth your while.

Do it yourself!

While I started the research in a lab, note that these materials can as well be grown from your own kitchen! I used the recipes by Suzanne Lee - BioCouture and Elise Elsacker – BioFabForum. Made it yourself? Share your findings in the comments below!

TextileLab Amsterdam is a creative research lab combining digital fabrication processes, biology, crafts techniques, textiles knowledge and material research into relevant opportunities for the textile, fashion and material fields and how these affect the way we work together towards change.

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