Raw silk needs to be processed before commercial use as it contains 20 to 30 per cent sericin, a silk protein, along with other impurities that make the silk thread coarse and lusterless and thereby concealing its merit.

Since sericin takes away much of the shining, removal of the protein through a process called degumming, increases the luster of silk, ML Gulrajani of textile technology department at IIT told PTI.

The enzyme-based degumming technology has been developed jointly by Gulrajani and Subhash Chand of the department of biochemical engineering and biotechnology in a project funded by the department of biotechnology (DBT).

Called ``fungal protease'' the enzyme needed for the process, was developed by Pune-based National Chemical Laboratory (NCL). IIT perfected the processing technology.

Thoughdegumming can be done by treating the fibre with an alkali at high temperature, the method damages the yarn.

Another drawback in the procedure is that the soap needed for processing is obtained from expensive olive oil which is not easily available in India, he said.

On the other hand, the enzyme-based method dissolves sericin uniformly at room temperature to produce undamaged milky-white silk.

Indian industry uses ordinary soap and alkali to remove the protein. But these reagents destroy the luster of the silk and make it yellow.

The enzymatic process does not cause any damage as it is carried out under mild reaction conditions, co-developer Subhash Chand, said.

The method is eco-friendly too as it does not release unwanted chemicals in the environment, he said.

The method can be extended to clean spun silk fabric that contains cellulosic and proteinous impurities.

``As India produces 15,000 tonnes of silk each year, the technology definitely has a commercial future,'' Gulrajani said.

About85 per cent of silk is consumed by the small scale industry to manufacture silk ``sari'' and other garments whose shine can be increased by this technology, he added.