The fashion industry is a major polluter. While many of us know about the textile waste from fast fashion and the fossil fuels used to transport our clothes, one area that often goes unnoticed is the impact of dyes.
Fashion is a colourful business that uses a wide range of pigments and colourants. Almost all of them, even those originally extracted from plants, are now produced from petrochemicals. One such example is indigo. A naturally occurring pigment, most indigo used today in the fashion industry is synthetic. Famously, it is the dye used to dye cotton in the production of blue denim, giving blue jeans their iconic colour. Over 50,000 tonnes of synthetic indigo are used every year by the denim industry.
To make blue denim, cotton yarns are run through a series of dyebaths containing indigo to give them their distinctive dark blue colour. The cotton is then woven together with a twill weave to create denim. This process is extremely water intensive (dyeing the equivalent of a single pair of jeans can use over 100 litres of water), and the indigo baths don’t just contain indigo and water but also highly alkaline and corrosive additives. One of the reasons indigo is used to produce blue denim is its properties allow for the application of later effects such as acid or stone washing, which further increases the environmental toll.
Toxic runoff is a serious issue, with water systems near factories often becoming contaminated. The impact is also felt by factory workers, who face health risks from constant exposure to dye baths.
Biosynthetic dyes
Replacing these synthetic dyes, and creating more sustainable dyeing processes, is therefore a key aim of those seeking to make the fashion industry more environmentally friendly. There are many exciting companies working in this space to produce new, environmentally friendly dyes using biological systems.
Colorifix is a UK-based startup producing dyes from bacteria and yeast. Not only do the cells produce the dyes, but they also can transfer the dyes into the fibre themselves, further reducing the impact of the dyeing process (i.e. no toxic dye baths). The microbes can also operate at a much lower temperature (around 37 degrees) compared to industrial dyeing processes (sometimes well over 100 degrees Celsius).
The company finds colours in nature, be it from insects, birds or bacteria and extract the relevant genes for insertion into their microbes. Instead of fossil fuels, Colorifix feeds its dye-producing microbes with molasses, a byproduct of sugar production. They’ve even trialled fermentation and dyeing with saltwater instead of freshwater, a breakthrough that could significantly reduce freshwater consumption in the textile industry.
Huue is a California-based startup seeking to create bio-based dyes through precision fermentation. They are initially focused on indigo. Huue uses genetically engineered microbes to produce indigo, thereby creating an identical product without the environmental harm of conventional synthetic indigo production.
Their approach may allow for easier and therefore quicker adoption by the textile industry as Huue’s indigo can be integrated into existing supply chains without significant changes. They have recently partnered with British fashion designer Patrick McDowell to create a capsule collection using Huue’s bio indigo dye.
Pili, a French biotech company, begins with renewable biomass and uses a hybrid process that combines industrial fermentation and organic chemistry to manufacture their bio-based dyes. They focus heavily on performance, aiming to match the quality, consistency, and scalability of synthetic counterparts so their dyes are viable replacements for traditional dyes.
Pili is also focused on indigo production given the high impact of the denim industry. Recently, they have partnered with clothing brand Citizens of Humanity to launch a capsule of denim clothing using Pili’s Eco-Indigo.
Living Ink, based in Colorado, is producing carbon-negative black pigments using algae. Algae waste and other agricultural water sources are processed to create their ALGAE BLACKTM pigment, which seeks to replace petrochemical-derived black pigments. The pigment can be added to a carrier to create black inks that can then be used both in garments and on packaging.
Nike has incorporated Algae Ink™ in its footwear line and British fashion designer Stella McCartney featured the pigment in her Spring 2024 collection.
Conclusion
There are still challenges ahead in incorporating these exciting new dyes into conventional supply chains. They still cost more than conventional dyes; however fashion consumers continue to become more eco-conscious and are driving demand for environmentally friendly clothing and apparel. Advances in the technology also continue to drive the costs down. Colourful clothing might soon be kinder to the planet.
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