Silk industry — the Indian queen of textiles — is embracing a transformative shift towards eco-friendliness! Indian researchers have for the first time identified eco-friendly solvents to replace the hazardous chemicals traditionally used in silk protein extraction processes that not only promises to revolutionise silk production but also addresses pressing concerns related to environmental impact and human health associated with conventional methods.
Traditionally, chemicals such as sodium carbonate, sodium hydroxide, sulfuric acid, and lithium bromide have been integral to the extraction of silk proteins from raw silk fibers. However, these chemicals not only are health hazardous for those involved in the process but also contribute to carbon emissions and environmental pollution as the chemicals are released in the water.
In response to these challenges, the research team led by Dr Kamatchi Sankaranarayan at Institute of Advanced Study in Science and Technology (IASST) Guwahati, an autonomous institute of Department of Science & Technology explored Ionic Liquids (ILs) as sustainable alternatives.
Ionic Liquids are salts that remain in a liquid state at relatively low temperatures and are known for their low toxicity and ability to dissolve a wide range of materials. This study, published in Chemistry Select by Wiley Publishers, marks a significant advancement in sustainable silk processing.
The researchers identified four ILs that effectively extract silk proteins from both mulberry (Bombyx mori) and non-mulberry silks such as Muga (Antheraea assamensis) and Eri (Philosamia ricini), which are native to Northeast India. Among these ILs, 1-Butyl-3-methylimidazolium chloride (BMIM.Cl), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM.BF4), and Tetraethylammonium bromide (TEAB) showed particularly promising results. TEAB, in particular, demonstrated the ability to efficiently destabilise sericin proteins while preserving the integrity of silk fibroin, essential for maintaining the quality and strength of the silk fibers, said Dr Sankaranarayan. This breakthrough not only aligns with global efforts to combat climate change but also highlights India’s commitment to sustainable development in its industrial practices.
By adopting ILs, the silk industry can move towards greener production methods, thereby promoting a cleaner and more sustainable future for silk manufacturing, he said.
Moreover, the extraction of sericin from non-mulberry silks using ILs opens up new possibilities for utilizing these unique fibers in various applications, including textiles, cosmetics, and biomedical products, said the researchers.
The green solvents are answers to the health menace for the workers involved in the silk processing. The chemical compounds create respiratory issues and are carcinogenic to humans, as indicated by dermatitis, skin lesions, back aches, bronchial asthma, coughs, gastrointestinal pains, ulcers, throat infections, thinning nails, dry skin, and hand and eye burning.
According to a study “Agrochemicals in sericulture and silk industry, and their effects on the human health and environment” published last year, “in addition to human concerns, persistent chemicals endanger the ecosystem and contribute to the overall chemicalization of aquatic and terrestrial environments. As a result, whenever possible, the discharge of toxic compounds into the natural environment should be reduced.”
Unfortunately, in developing countries like India, where large quantities of these chemicals are generated and dumped into the environment, they are not properly managed because little is known about their potential risks and benefits if properly managed, said the study authors J Harishkumar , R. Ravi Kumara, MS Santhosh and K Ravikumara from University of Mysore, Mysuru.
In fact, according to reports, scientists and innovators across the world are working towards creating a new generation of silk fabrics that can match the textile’s positive attributes without harming the environment, according to the latest report from the Material Innovation Initiative (MII).
India, as the second-largest producer of raw silk globally, holds a unique position for its diverse silk production. The country stands out as the sole producer of five distinct types of silks worldwide. Mulberry silk, primarily cultivated in states like Karnataka, Tamil Nadu, Telangana, dominates the production landscape, comprising nearly 70% of India’s total silk output. Karnataka leads the production of mulberry silks, underscoring its pivotal role in the national silk industry.
Apart from mulberry silk, India boasts non-mulberry varieties known as Vanya silk, including Tussar from states such as Chhattisgarh, Jharkhand, Odisha, and West Bengal. The northeastern region contributes significantly with Muga silk from Assam and Eri silk from Meghalaya and Nagaland, each prized for their unique qualities and traditional significance.
