Enzymatic Preparation of Machine-Washable Antibacterial Wool through a Subtraction-Addition Technique Using Hydrolase and Transglutaminase

Enzymatic antifelting finishing, as an eco-alternative for conventional chlorination, has attracted increasing attention in wool processing. Nevertheless, proteases are often subject to the disadvantage of significant fiber damage, which is mainly due to the hydrolysis of low-crystallinity cell membrane complexes rather than wool scales. Herein, a full enzymatic subtraction-addition approach was applied to the antifelting finishing of wool textiles, that is, the enzymatic hydrolysis of the highly cross-linked wool scales was carried out by using the hydrolases of keratinase and protease, and then, a glutamine-modified epsilon-poly-l-lysine (mPLL) was grafted to wool fibers under the catalysis of transglutaminase for enhancing the antifelting effect. According to the test standard of IWS-31, the shrinkage rate of the obtained wool fabric was reduced to 2.98%, and the strength loss was less than 10%, accompanied with encouraging antibacterial activities against Staphylococcus aureus and Escherichia coli, both reaching 100% of antibacterial rates after contact with the bacteria. Meanwhile, low-temperature dyeing can be achieved by enzymatically reducing the density of wool scales, and the mPLL network formed on the wool surface ensures a satisfactory colorfastness to washing and rubbing up to level 4.5. The present enzymatic subtraction-addition technique provides a green route for the functionalization of wool textiles.