Cellulases break down microfibrils on denim fibers’ surface to release indigo. That exposes the undyed interior for a stonewashed effect without pumice stones.

The indigo used to dye denim only penetrates the surface of the yarn fiber. That leaves the center light in color. 

The cellulose molecules that form the fibers of cotton fabrics consist of long glucose chains. Cellulase molecules bind to exposed microfibrils on the surface of the yarn and break them down. That - along with mechanical action - releases blue indigo dye from the surface. Cellulases leave the interior part of the cotton fiber intact. The result is that the lighter areas in the interior of the fiber become visible and appear as fading on the surface of the denim. Textile laundries use cellulases to get fashionable stonewashed looks without the use of pumice stones.

A small dose of a cellulase product can replace several kilograms of stones. That means less wear on machines, less pumice dust in the working environment and less sediment in wastewater. It also means no need for time-consuming removal of dust and small stones from the finished garments. Fewer stones in laundry machines means more room for garments, which improves productivity. Cellulases also minimize strength loss and can reduce back staining compared with stonewashing.  

Stonewashing creates substantial amounts of sludge. This has an environmental impact and leads to high treatment costs. With cellulases, textile laundries can avoid these costs and reduce their environmental footprint.