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.