The term ‘Fast fashion’ describes a business model that is making
fashion trends quickly and cheaply available to consumers. It is responsible for
almost 10 percent of global greenhouse gas emissions (1). Withal, this profit-orientated
sector has the second largest water consumption, is responsible for ~20% of industrial
water pollution from textile treatment and dyeing, contributes to ~35% of oceanic primary
microplastic pollution and produces vast quantities of textile waste, much of which ends
up in landfill or is burnt, including unsold product (2).
To give one example of the water consumption of the fashion industry:
20 000 liters of water are needed in order to produce one pair of jeans and one t-shirt.
Despite the awareness of the environmental and social consequences of fast fashion,
the production capacity of this industry keeps increasing as well as its environmental footprint (3).
Figure 1) Estimated impact of the textile industry in 2025 compared to 2015. Displayed are CO2 emissions, water and land use. Adapted from (3).
This phenomenon can be explained by the business models Fast Fashion relies on.
They instil a sense of urgency and support impulse purchases (4). For instance, Zara offers 24 new
clothing collections each year, H&M offers 12 to 16 and updates them weekly. Increasing production
rates, while reducing prices, product quality and product life cycle leads to an unsustainable
overconsumption and waste of material, energy and resources. As a result, in 2010, textile output
surpassed world population growth, a consequence of the rise of low-cost manufacturing and fast fashion (2).
Figure 2) Growth of textile production and world population from 1970 to 2020. Fibre production includes cotton, polyester, non-cotton cellulosics, polyamide and polypropylene, silk and wool. By the 2010s, textile-production growth overtook world-population growth, largely driven by the rise of cheap manufacturing and fast fashion. Adapted Figure 1 from (2).
In order for a sustainable system to arise, both production techniques and consumer
attitudes must be changed. Investmenting in clean technologies and changing business models of the
textile sector is as important as leading consumers to change their purchasing habits (2).
Indigo is the oldest and one of the most consumed dyes in the textile
sector. It has an intense dark blue color and is nowadays widely used for the dyeing
of denim clothes (7). Despite its large number of advantages, indigo has several environmental
drawbacks. About 15% of indigo used in the dyeing process is discharged to wastewater treatment
plants, sometimes even into rivers, in countries where regulations are not strictly applied (8).
Most of the indigo is currently produced by chemical synthesis and its production process
therefore requires large amounts of chemicals The organic synthesis of indigo was introduced
in 1925 by BASF based on work by Baeyer and is still in use today (9).
Figure 3) Organic synthesis pathway from aniline to indigo. Adapted from (9).
In this process aniline - a famous petroleum derivative is used as well as
dangerous chemicals - formaldehyde, hydrogen cyanide, and sodium amide. Large amount of
solvent is also used (7).
The issue of sustainability is clear with synthetic indigo. As an alternative, indigo
can be also produced with plants or bacteria. But is natural indigo more sustainable?
To answer this question, we went to Bordeaux to visit a craftsman for the production of natural indigo.
Learn more about this journey by clicking this link to our Integrated Human Practices page. Within fast
Fashion, we identified the production of indigo and the process of dyeing textile with it as a problem.
Our goal was to suggest an alternative solution. By engineering bacteria to produce indigo, we aimed to
create a new method of textile indigo-dyeing. No chemicals or petroleum derivatives are required during
the entire process.