The colour in our clothes has many serious environmental consequences, from the use of fossil fuel by-products to manufacture dyes to the heavily polluted water left after dyeing. But a UK-based company called says it can greatly reduce these impacts by using microbes both to make the dyes and to help fix them to fabrics.
鈥淲e鈥檝e had considerable interest in this, because consumers are really starting to think about what they wear and how it damages the environment,鈥� says chief science officer Jim Ajioka.
Back in 2013, Ajioka was looking at ways of monitoring water pollution with another researcher, Orr Yarkoni. When the pair realised that much of the water pollution in Nepal and Bangladesh came from the dyeing of textiles, they started thinking about how to reduce it.
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Their solution is to use genetically modified bacteria or yeast to 鈥済row鈥� dyes, instead of manufacturing them from chemicals derived from fossil fuels. Ajioka and Yarkoni founded Colorifix in 2016 to commercialise the process.
Some of the colours produced by the modified microbes are pigments long used for dyeing, such as the indigo that gives denim its colour. Others are novel dyes never used before, such as a reddish pigment found in a mould that can grow in showers.
When textiles are put in the vats where the microbes are growing, the cells attach themselves to the fibres. This means they are producing the dye exactly where it鈥檚 needed, says Ajioka. 鈥淭hey like going onto surfaces,鈥� he says. 鈥淭hat鈥檚 a real advantage that we have.鈥�
In fact, the microbes naturally work their way inside the fibres. In conventional dyeing, fabrics instead have to be heated to up to 130掳C (266掳F) to open up the fibres so dyes can get inside them. 鈥淵ou waste a lot of energy going up to these very high temperatures to open up the fibres,鈥� says Ajioka.
The Colorifix process does involve heating to burst open the microbes and release the dyes they have made, but not to such high temperatures.
Conventional dyeing also involves adding chemicals known as mordants that help fix colours to fibres. Chromium is widely used, but it is highly toxic.
Sodium, potassium and magnesium can also be used as mordants, says Ajioka, and they are naturally found within cells. So the microbes also provide the mordants when they burst open.
The final stage of dyeing is washing away excess dye, which usually requires several washes. But because the microbes release dyes directly onto the fabric, there is much less excess and only a single wash is needed, says Ajioka.
According to the company, the process uses about half as much energy and a quarter as much water, with the leftover liquid containing only biodegradable substances. Water authorities in Cambridge gave the company permission to put it straight into sewers after testing it, says Ajioka.
The only downside is that the microbes are fed nutrients derived from soya, which might lead to an increase in the area of land that is farmed, and thus to more deforestation and carbon emissions. However, the impact is likely to be tiny compared with, say, making jet fuel from palm oil.
鈥淭his innovative microbe-based dyeing technology offers significant environmental advantages, such as reducing the need for large quantities of water and harmful chemicals that are typically required for pigment extraction and dye application,鈥� says at the University of Georgia in the US, who has no connections to the company.
Colorifix has already dyed small quantities of clothing sold in conjunction with H&M in the UK. But the business plan is to license the microbes, growing equipment and know-how to existing dyeing companies. 鈥淲e鈥檙e setting up in India now,鈥� says Ajioka.
The company is one of several aiming to make the dyeing industry greener. At least three 鈥� , and 鈥� have developed processes that are more like printing than conventional dyeing. Sharma鈥檚 team, meanwhile, has created a way of dyeing denim that involves attaching indigo to cellulose nanofibres that then bind to the cotton.
All are claiming big reductions in water and energy use, but unlike Colorifix, these processes still rely on conventionally made dyes.
Quantifying the environmental benefits of getting microbes to make dyes instead is nigh-on impossible, says Ajioka. 鈥淲e鈥檙e never going to get metrics off a dye manufacturer, because the supply chains for any petrochemical process are so intricate.鈥�
