Silkworms That Spin Colorful Silk Fibers

Scientists have discovered a ‘greener’ dyeing method to producing colorful silk: by feeding dyed leaves to silkworms so they spin colored – rather than white – cocoons.

AsianScientist (Dec. 13, 2013) – For some 5,000 years, cultivated silkworms have been spinning luxurious white silk fibers destined for use in the finest clothing.

But current dyeing practices produce wastewater that contains potentially harmful toxins, so scientists are turning to a new, “greener” dyeing method in which they coax already-colored fibers from the caterpillars by feeding them dyed leaves. Their findings are published in the journal ACS Sustainable Chemistry & Engineering.

Dyeing textile fabrics is one of today’s most polluting industries. The process requires huge quantities of water for bleaching, washing and rinsing, and it results in a stream of harmful wastewater that needs to be treated effectively before release into the environment.

To make the industry greener and more environmentally friendly, researchers Anuya Nisal, Kanika Trivedy and colleagues from the CSIR-Indian Institute of Chemical Biology in West Bengal, India have been developing less toxic methods, including feeding dyed leaves to silkworms so they spin colored — rather than white — cocoons. But so far, this technique has only been tested with one type of dye, which is too pricey for large-scale production. Thus, the team turned to azo dyes, which are inexpensive and account for more than half of the textile dyes used today.

They dipped or sprayed mulberry leaves, the silkworm’s food of choice, with azo dyes to see which ones, when consumed, would transfer to the silk. Of the seven dyes they tested, three were incorporated into the caterpillars’ silk, and none seemed to affect the worms’ growth. The scientists noticed that certain dye traits, such as the ability to dissolve in water, affected how well the dye worked.

The team hopes that to develop novel dye molecules that can be successfully used in this green method of producing colored silk fabrics.

The article can be found at: Nisal A et al. (2013) Uptake of Azo Dyes into Silk Glands for Production of Colored Silk Cocoons Using a Green Feeding Approach.

——

Source: American Chemical Society; Photo: 白石崖/Flickr/CC.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Asian Scientist Magazine is an award-winning science and technology magazine that highlights R&D news stories from Asia to a global audience. The magazine is published by Singapore-headquartered Wildtype Media Group.

Related Stories from Asian Scientist