While caustic soda is used for a weight-reducing treatment of polyester, a cellulase is used for a weight-reducing treatment of cotton. In case of treating cotton with a cellulase, the weight reduction of around 1 to 5% is usually achieved. The principle object of the weight-reducing treatment is to improve hand feeling, but it is also utilized for other purposes such as removing fibril.
The most important point in the weight-reducing treatment with cellulase is that a physical action applied on fabrics will greatly improve the weight-reducing ratio. This feature cannot be seen in other treatments with enzymes, such as a desizing treatment with amylase, and a boil-off treatment with protease. Accordingly, machines suitable for the weight-reducing treatment are a washer, a jet dyeing machine, etc. in the priority order. Balls may be used in the washer to further increase the physical action on the fabrics.
One thing you have to be careful in the weight-reducing treatment with cellulase is a possible decrease in fabric strength. The extent of the decrease depends on a fabric type and an employed machine, and so they need to be checked every time.

Cellulase is generally a multienzyme, and is composed of (1) endo-cellulase that randomly hydrolyzes non-crystal components of cellulose, (2) exo-cellulase that hydrolyzes a cellulose chain in cellobiose units from the nonreducing end of the cellulose chain, and (3) glucohydrase that acts on cellobiose cello-oligosaccharide to generate glucose.