Bio-Polishing: Bio polishing is a process that uses cellulase enzymes to remove fuzz or loose fibers and dead cotton from the cotton fabric.or yarn. This treatment is designed to improve fabric quality and provide following advantages:

•         Improve pilling resistance

•         A clear, lint and fuzz-free surface structure

•         Improved drape and softness

•         The effect are durable

Removal of protruding fibres from garment surface using cellulase enzymes is called bio-polishing. These enzymes are proteins and capable of hydrolysing cellulose (cotton). In bio-polishing they act upon the short fibres protruding from fabric surface and make the fibres weak which are easily removed during washing. This process imparts soft and smooth feel and reduces fuzz or pilling tendency. This process is applicable to garment or fabric made of cotton and its blends. 

Most of the cases it is considered as a finishing process e.g. in the case of Denim washing to create fading effect. But in some of the cases it is used in the before dyeing such as in knitted cotton fabric to imitate outcome of the singeing process.

Cellulases are derived from both fungal and bacterial sources. They find extensive application on cellulosic materials and about 1 0% of the finishing of these materials is estimated to be performed by these enzymes to achieve various effects. They also find application in food, pharma and paper industries.

Cellulases have a protein like structure are susceptible to degradation due to temperature, ionizing radiation, light, acids, alkali, and biological effect factors. Cellulases are capable of breaking the 1,4-B-glucoside bond of cellulose (cotton) randomly under optimum conditions. It resulted smooth fabric surface with the loss of surface fibres and the hand becomes soft. There is also loss in strength proportional to the amount of weight reduction. 

There are mainly three types of cellulases:

1) Acid stable or acid enzyme (more effective in pH range of 4.5 - 5)

2) Neutral stable or neutral enzyme (effective at pH 7)

3) Alkaline or alkaline enzyme stable (not used widely) 

Following recipe may be used for biopolishing of cotton fabric using acid enzyme:

•         Enzyme dosage 1-2% owf

•         pH 4.5-5.5

•         Temperature 40-55^oC

•         Time 30-60 min.

To prevent any damage of the cotton fabric after this operation it is very essential that the reaction be terminated at the end of treatment. The process is called deactivation or enzyme inactivation. If the enzyme is not inactivated entirely then at the end of the reaction fibres get damaged and even extreme cases total destruction of the material may be resulted. The enzyme inactivation is therefore of great importance from the technical point of view. 

There are two distinct process of termination of enzyme:

1) Hot treatment at 80 0C for 20 minutes.

2) By raising the pH to 11-12.

Advantages: Following are important advantages

1. Hairiness, fluffs and pills are removed and thus reduce pilling problem.
2. Improve fabric hand
3. Smooth surface and Improved lustre.
4. Improved sewability.
5. Environment friendly as no harsh chemical is used

Disadvantages: Following are disadvantages out of this treatment. Both are linked together:

1. Loss in weight
2. Loss in strength