Cellulase immobilization onto the reversibly soluble methacrylate copolymer for denim washing

• The aged look of denim fabrics is obtained by the action of the immobilized cellulase.
• The immobilized cellulase treatment of the fabrics showed lower weight loss.
• The immobilized cellulase treatment of the fabrics showed higher tensile strength.
• The immobilized cellulase has great potential in the enzymatic laundry of denim fabrics.

Cellulase treatment of denim fabrics is an environmentally friendly way for producing desired worn look. In this work, the enzymatic treatments of the denim fabrics, i.e., bio-washing, using native cellulase and cellulase immobilized with reversibly soluble copolymer (Eudragit S-100), immobilized-cellulase, have been investigated. According to the analyses of the lightness (CIE L value), color strength (K/S value) and color variations, at a cellulase concentration level of 6% o.w.f., the denim fabrics treated with the immobilized cellulase showed decoloration and color effect close to the native cellulase. However, the immobilized cellulase treatment of the denim fabrics showed lower weight loss and considerably higher tensile strength than those treated with the native cellulase. Both the native and immobilized cellulases improved the crystalline indice and the apparent crystallite size of the fiber sample compared with the control ones. The amorphous portion of the cellulose suffered more hydrolysis by the native cellulase than the immobilized cellulase. Scanning electron microscope pictures (SEM) and digital pictures further indicated that the immobilized cellulase can efficiently remove indigo dyestuffs on the surfaces of the denim fabrics without the problem of excessive damage to the fibers.