Bio Washing Enzymes

Abrasion Yarn the abrasive action of lightweight pumice stones on the garment surface, which removes some of the dye. However, too much abrasion can damage the fabric, particularly hems and waistbands. This is why denim finishers today use acid, hybrid or neutral cellulases to accelerate the abrasion by loosening the indigo dye on the denim. Since a small dose of enzyme can replace several kilograms of stones, the use of fewer stones results in less damage to garments, less wear on machines, and less pumice dust in the working environment. Productivity can also be increased through laundry machines containing fewer stones but more garments. With a stone-free process, the need for the removal of dust and small stones from the finished garment is reduced. There is also no sediment in the wastewater, which can otherwise block drains. Denim garments are dyed with indigo, which adheres to the surface of the yarn. The cellulase molecule binds to an exposed fibril (bundles of fibrils make up a fibre) on the surface of the yarn and hydrolyses it, but leaving the interior part of the cotton fibre intact. When the cellulases partly hydrolyse the surface of the fibre, the indigo is partly removed and light areas are created.

Neutral cellulases or Neutrastone Series designed by AETL acting at pH 6-8, acid cellulases (Denicell Series) acting at pH 4-6 and hybrid cellulases (Addcool Series) acting at pH 5 - 6.5 are used for the abrasion of denim. There are a number of cellulases available, each with its own special properties. These can be used either alone or in combination in order to obtain a specific look. Application research in this area is focused on preventing or enhancing backstaining depending on the style required. Backstaining is defined as the redeposition of released indigo onto the garments. This effect is very important in denim finishing. Backstaining at low pH values (pH 4-6) is relatively high, whereas it is significantly lower in the towards neutral pH range. Neutral cellulases are therefore often used when the objective is minimal backstaining. Hybrid cellulases are effective tool to save energy cost as processing can be done at ambient or room temperature conditions.

Backstaining is not the cause of worry now a days due to availability of effective anti backstaining agents based on chemicals. AETL is one of the first companies to introduce backstaining removing enzyme (Stain Clear Series), unlike chemical agents which are used to prevent backstaining. Products are based on blends of different proteases, lipase and endolase.

Enzymes have opened up new possibilities in denim finishing by increasing the variety of finishes available. For example, it is now possible to fade denim to a greater degree without running the risk of damaging the garment. This can be effectively done by using enzymes like Laccase or peroxidase replacing bleaching chemicals like hydrogen peroxide or hypochlorite. Peroxidases introduced by AETL as Ecowash BB are further advantageous over Laccase as it has to be used in neutral pH 6 - 7 and temperature 50 - 55 0C. The denim industry is driven by fashion trends. The various cellulases available for modifying the surface of denim give fashion designers a pallet of possibilities for creating new shades and finishes. The combination of new looks, lower costs, shorter treatment times and less solid waste has made abrasion with enzymes the most widely used fading process today. Incidentally, since the denim fabric is always sized, the complete process also includes desizing of the denim garment.