1.0. Cleaning the fashion industry’s polluted footprint — with Synthetic Biology
We’re using bacteria to wipe out harmful denim dyes. We’re turning cotton-clothes to fungi-fabric. Synthetic biology is transforming the way we make the things we wear, paving the way for more future sustainable fashion.
Each pair of jeans in your closet took 1,800 gallons of water to make, the toxic indigo dye responsible for 20% of the world’s water pollution. On top you wear your leather jacket, which took tremendous amounts of energy and chemicals to transform the animal skin into wearable fabric.
Synthetic biology has already long been playing a role in the textile industry. Enzymes are being used at a mass scale to bleach and wash fabrics. But we’re beginning to turn this technology up a notch, taking advantage of the abilities of living microbes to dye denim and creating clothes from fungi grown on disks — ditching many of the clothing production processes which make the fashion industry one of the most polluting across the globe.
Dying the future of jeans, with microorganisms
They begin as strings of cotton yarn which bobble as they are woven in bubbling hot water and vats of indigo dye. The fabrics are put through at least a dozen cycles as you watch them turn from a weird yellow to a green to finally the denim blue that you’re too familiar with.
Currently, the production of the colour indigo is made through using toxic chemicals and reducing agent. The pigment indigoidine, was first harvested in India from the Indigofera plant which stores chemicals in their leaves. Although the actual substance itself isn’t scarring, the chemicals used to make it water soluble and applicable onto clothing are.
The status quo works like this:
- Indican, the chemical precursor to indigo is produced from a natural indigoidine pigment
- This is then transformed into leucoindigo, the actual dye on the cotton using an enzyme called β-glucosidase
- But to convert the indican to leucoindigo so the dye can crystalize and change the colour of the cotton, cheap but extremely toxic substances (such as sodium dithionite) are mixed with the water
But it was later discovered that the bacteria E. coli could be used to sustainably produce this leucoindigo through cutting out many of the previously required chemicals. This leucoindigo can even be implemented straight into existing dyeing facilities without the need for a machine or equipment swap.
Or the indican solution produced from the E. coli can be sprayed onto white cloth and then dipped into a solution of a glucosidase enzyme. After it’s removed, the indican oxidizes into indigo, which then sticks to the fibers and is retained even through rigourous washing. Although the resulting blue isn’t as dark as through conventional methods, the dying process can be repeated multiple times in order to achieve the desired shade. As you can see, the final result is identical to traditional indigo dying!
A typical dress, this time not made of cotton but fungi
The creation of leather is not only complicated (23 steps), expensive, and lengthy but is one which is certainly not environmental sustainable.
In a nutshell, this is how the current process follows:
- Cured hides are soaked in pools of water for several days to help add moisture and clean off salt and dirt
- The skin are then drenched in toxic weak acid and salt solutions in preparation for converting it into a stable material
- The leather is then tanned using salts of chromium (dangerously toxic)
- Sometimes it then goes on to be dyed a colour, either just on the surface, or with more penetrative staining, which calls for another list of horrible artificial chemicals
Which is why bio-fabrication (is an area within the realm of synthetic biology) sounds like an incredibly interesting process. The idea of growing materials from nature’s smallest organisms with little energy and no man-made chemicals is truly exciting and one of the fastest growing in the sphere of science.
A Dutch company called NEFFA, founded by Dutch fashion designer Aniela Hoitlink, is experimenting with the material made from Mycelium, the roots of typical mushrooms that you can eat. It creates a fabric called Muskin, which can be thought of as your plant-version leather, is created by growing these roots in petri disks. The disks are then layered upon each other to form a thin fabric which is then molded onto a mannequin, no sewing required.
The production of Mycelium can be done in a controlled environment with agricultural waste, requiring very limited amounts of energy to flourish. The process is alike to fermenting, and other designers have begun to experiment with substances such as sugar, green tea, and yeast to make various fungi-fabrics. There are zero toxic chemicals or fertilizers used to grow the mushroom roots or to stick the fabrics together, using only 12 litres of water per garment and producing 0 kg of CO2— which put into context is 148 litres less and 8kg than it takes to make 1 kg of leather.
And if you decide to dispose of the clothing, the fast biodegradable properties ensure the fabric returns to the soil, no harm done. They can even be used as fertilizer compost if you need!
Scaling up
While these are revolutionary breakthroughs, the greatest challenge remaining now is how we can take these ideas and scale the processes to an industrial volume. Startups are beginning to recognize the power of synthetic biology, but we still need years to ensure the word spreads out to the rest of the world. For now I guess I should look into where I can get one of these E. coli dyed jeans or fungi dresses for my next online shopping trip!
- Ashley
