Biotechnology, or more specifically enzyme technology, has enormous potential for production and synthesis of textiles with advanced functionalities. This is because of the high specificity of enzymes, explain Harshita Chaudhary, Deepti Gupta and Charu Gupta.
Enzyme technology has proven to be profitable in industrial textile pre-treatment processes of natural fibres. These processes include desizing, scouring and degumming.
The good news is, application of enzymes is not limited to natural materials. It has recently been demonstrated that enzymes are able to modify surfaces of synthetic textiles like polyester. The major advantage of enzyme processes lies in their surface-specific, pro-environment, energy saving process conditions.
Investigators indicate that enzymes degrade polyester in a two-step reaction. The first is hydrophobic adsorption onto the polyester surface followed by the hydrolysis of the polyester ester bonds. Practically, the first step is surface erosion. Because of the large size, the enzymes cannot penetrate the fibre and hence are restricted to reacting on the surface. In the second step, enzymes catalyse the hydrolysis of ester bonds in the polymer. This results in generation of reactive groups such as carboxyl and hydroxyl groups on the fabric surface.
The appearance of polar groups on the surface of polyester provides an opportunity to improve many unfavourable properties of polyester. Bio-catalytic modification results in improved moisture-related properties, fabric handle, electrical conductivity and resistance to soiling with reduced gloss and susceptibility to pilling. The advantage of enzymes over conventional techniques is that the favourable bulk properties of polyester are not affected because the enzymes are too big to penetrate the bulk phase of the material.
A variety of enzymes can be used to modify the surface of polyester. Over the last few years, much research has focused on potential of lipases and cutinases for functionalisation of polyester. Both carboxyl esterases or lipases and cutinase are carboxylic ester hydrolases and members of esterases enzymes that hydrolyse ester into an acid and an alcohol.
Mechanism of polyester modification using enzymes