Photo by Shutterstock

Scientists have discovered a better way to obtain colored silk from silkworms. By feeding silkworm larvae a modified diet of spray-dyed mulberry leaves, researchers from the National Chemical Laboratory in India were able to obtain “intrinsically colored” cocoons without the vast amounts of water and chemicals associated with the traditional dyeing process. Textile dyeing is one of the most polluting aspects of the garment industry, demanding mammoth quantities of water for bleaching, washing, and rinsing. Most methods also result in a stream of toxic effluent that requires extensive treatment before it’s released into our waterways.

PREVIOUSLY ON ECOUTERRE: New Silkworm Diet Naturally Dyes Silk, Reduces Water Consumption

American Chemical Society, silkworms, silk, natural dyes, all-natural dyes, eco-friendly dyes, eco-friendly textiles, sustainable textiles, eco-textiles, eco-friendly fabrics, sustainable fabrics, eco-fashion, sustainable fashion, green fashion, ethical fashion, sustainable style, Anuya Nisal, Kanika Trivedy

Photo by Shutterstock


A diet of dyed leaves that coaxes silkworms to spin colored, rather than white, cocoons, on the other hand, could do much alleviate this enormous environmental burden. Still, there’s one kink in the scheme: Not all colorants will work the same way. To test the technique, Anuya Nisal, Kanika Trivedy, and their colleagues turned to AZO dyes, a class of inexpensive synthetic chemicals employed by more than half of the world’s textile mills despite reports of carcinogenic properties. (That’s a whole other kettle of tinctures to explore.)

Of the seven dyes they tested, only three were incorporated into the caterpillars’ silk.

Of the seven pigments they tested, only three were incorporated into the caterpillars’ silk. (None, they noted, appeared to affect the silkworms’ growth.) Nisal, Trivedy, and their team found that certain traits, such as the ability to dissolve in water, affected the efficacy of the dye.

Their conclusion? More work needs to be done before a one-size-fits-all solution can be found. Still, the work is not naught. “These insights are extremely important in development of novel dye molecules that can be successfully fed to Bombyx mori silkworm larvae for producing intrinsically colored silk of various colors and shades,” they write in their report.

+ Press Release

+ American Chemical Society