An eco-friendly technique for shrink-resist finishing of dyed wool via combined use of hydrolase and cyclamate

Abstract

Savinase 16L as a type of mature protease for shrink-resist finishing can effectively hydrolyze wool scales, but it is also easy to penetrate into the cell membrane complex (CMC) layer, even easily causing undesired fiber damages. In this study, Savinase 16L was combinedly used with a protective agent of cyclamate, achieving an increase in the size of enzyme protein molecules through the intermolecular forces. This combined operation was intended to make it difficult for protease to enter the CMC layer, conferring protease a more concentrated actions towards wool scales. Meanwhile, a commercial keratinase was applied for wool pretreatment to loosen the structural integrity by hydrolyzing the disulfide bonds in wool scales. The combination use of hydrolase (20 U/mL of keratinase, and 6.5 U/mL protease) and 10 g/L cyclamate endowed the dyed wool fabric with encouraging shrink-resist property, achieving a felting shrinkage of 5.4% ± 0.55% with an acceptable strength loss of 12.3% ± 1.2%. More importantly, color hue of the wool fabric almost did not change compared with to that with chlorination method. As an eco-friendly and energy-saving strategy, it provides an efficient alternative for shrink-resist finishing of white and dyed wool fabrics, and expands the application of biotechnology in wool industry.