Eco-friendly solvents offer solutions for sustainable and diverse silk industry

Researchers have found an eco-friendly approach that can eliminate the use of toxic chemicals in silk processing.

Traditionally, toxic chemicals like sodium carbonate, sodium hydroxide, sulfuric acid, and lithium bromide have been used to extract silk proteins, fibroin and sericin from various types of raw silk fibers, an important step in the process of making silk from cocoons.

A team at Institute of Advanced Study in Science and Technology (IASST) Guwahati, an autonomous institute of Department of Science & Technology, has identified Ionic Liquids (ILs) which can be promising sustainable alternatives to the toxic chemicals currently in use for the silk protein extraction process.

The team led by Dr. Kamatchi Sankaranarayan has identified 4 different ILs that can be effective in extracting silk proteins from raw fibres.

This new research, published in Chemistry Select by Wiley Publishers, has potential for use in sericin extraction from both mulberry (Bombyx mori) and non-mulberry silks, such as Muga (Antheraea assamensis) and Eri (Philosamia ricini), indigenous to Northeast India.

The researchers explored six different ILs and found some of them were particularly effective in removing sericin without damaging the silk protein structure. The ones showing greatest promise included 1-Butyl-3-methylimidazolium chloride (BMIM.Cl), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM.BF4), and Tetraethylammonium bromide (TEAB). TEAB appeared to be highly effective due to its ability to destabilize sericin proteins.

The research holds great significance for the silk industry. Not only does it offer a more environmentally friendly alternative to traditional chemical methods, but it also paves the way for efficient sericin extraction from non-mulberry silks, potentially leading to new applications for these unique fibers.

This is the first instance of using ILs for sericin extraction from non-mulberry silks, highlighting the potential of this new approach for a more sustainable and diverse silk industry.