Industrial production of a colourless compound found in indigo plants could one day provide a way of dyeing blue jeans that is less environmentally harmful and safer for workers, according to international research. Blue jeans are currently coloured with a dye called indigo – a process the researchers say generates significant carbon dioxide emissions along with toxic chemicals that could be exposing workers to health risks. The researchers say indican, a colourless compound found in the same plants that produce indigo, could be a healthier solution if produced on a mass scale. They say they were able to engineer an improved enzyme that could produce indican on an industrial scale, as well as processes that could convert the indican to indigo and dye the denim using light.
Journal/conference: Nature Communications
Link to research (DOI): 10.1038/s41467-024-45749-3
Organisation/s: Technical University of Denmark, Denmark
Funder: The authors thank Carlotta Chiesa, Carsten Dam-Hansen, Dennis Dan
Corell, Andreas Worberg, Nemeh Bani Odeh, and Gossa Garedew
Wordofa for CIEL instrument time and technical assistance. This work
was funded by the Novo Nordisk Foundation through grants NNF10CC1016517 (to the Novo Nordisk Foundation Center for Biosustainability),
NNF20CC0035580 (to the Novo Nordisk Foundation Center
for Biosustainability), NNF16OC0019088 (to D.H.W), and Carlsberg
Foundation through grant CF18-0631 (to K.Q.).
Media release
From: Springer Nature
Sustainability: A potential greener way to dye denim blue
New methods that could reduce the environmental and societal impacts of blue denim production are reported in Nature Communications. The authors suggest that these methods could reduce the environmental impact of blue denim dyeing by up to 92% and prevent denim mill workers from being exposed to harmful chemicals, with only a modest cost increase.
The production of blue denim, a billion-dollar industry, currently uses a dye called indigo — the only known molecule that can provide the unique colour of blue denim. This process generates significant CO2 emissions and involves large quantities of toxic chemicals, which can cause environmental pollution and impact the health of textile workers and local communities. Indican, a colourless precursor to indigo, offers an ecologically attractive alternative to dyeing denim as harsh chemicals are not required and it can be converted into indigo directly on the yarn. However, to adopt this approach, methods to produce large quantities of indican are needed.
Ditte Welner, Katrine Qvortrup and colleagues engineered an improved enzyme variant of an enzyme called indoxyl glycosyltransferase, found in the indigo-producing plant Polygonum tinctorium, capable of economically producing indican on an industrial scale. They also demonstrated economically feasible and low-impact dyeing processes to convert indican to indigo and dye the denim, including an approach using enzymes and a light-driven approach. For the latter, various light sources were shown to help dye the denim in a solution with the fabric, including energy-efficient LEDs, natural light, and even a household light bulb. Light-driven dyeing may have the potential to reduce the environmental impact of blue denim dyeing by 73%, compared to a 92% reduction with enzymatic dyeing. The authors suggest that these methods could reduce the production of toxic waste and decrease the yearly global CO2 emissions by 3,500,000 tonnes, given that 4 billion pairs of jeans are traded every year, according to market analyses.
The authors suggest that a reduced environmental impact could provide an incentive for more localized production in the Western denim market, which may enhance supply chain transparency and sustainability in the textile industry.
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Springer Nature is committed to boosting the visibility of the UN Sustainable Development Goals and relevant information and evidence published in our journals and books. The research described in this press release pertains to SDG 12 (Responsible Consumption and Production). More information can be found here
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