New Laccase-Mediated System Utilized for Bio-Discoloration of Indigo-Dyed Denim Fabrics

In this study, indigo-dyed denim fabric was decolorized by washing and printing with separate and simultaneous applications of laccase enzyme, sodium hydrosulfite, and cellulase enzyme. In this regard, the surface reflectance and color coordinates of the discolored fabrics were analyzed, and SEM photographs of the treated fabrics were prepared to analyze their surfaces. Finally, the effects of the discoloration process and materials on various parameters of the treated samples were investigated, including moisture content, creaserecovery angle, air permeability, and abrasion resistance. The color experiments showed that the discoloration mechanism with the combined use of laccase enzyme, sodium hydrosulfite, and cellulose enzyme had a significant effect on the improvement of the lightness (L*) of the samples, as the lightness of the treated samples was improved by 101.18 percent and 55.79 percent in both printing and washing, respectively. Furthermore, examination of specimen color coordinates revealed that the hue of the treated samples was changed to blue and green, and the purity of color (C*) was improved. The increased moisture content and air permeability of the treated specimens suggested that the comfort of the jeans clothing provided by these treatment methods had improved. As a result, it should be noted that the mediating action of sodium hydrosulfite was significantly influential for discoloration of denim with the laccase enzyme.