Integrated desizing–bleaching–reactive dyeing process for cotton towel using glucose oxidase enzyme

Series of individual preparatory processes prior to dyeing for cotton towel are unavoidable that not only produce a polluted discharge but also require an enormous amount of utilities. We report integration of desizing, bleaching and dyeing processes without discharging each spent bath using enzymes in batchwise method. The desizing effluent discharge eliminated by using Amyloglucosidase–pullanase enzyme to produce glucose; and glucose oxidase (GOx) enzyme (Aspergillus oryzae) to generate hydrogen peroxide (H2O2) that yielded 85 mg/L in the spent bath. In the subsequent bleaching step, conservation of fresh water was also realized. The spent bleached bath was further treated with catalase enzyme to remove residual H2O2 and to carry over the reactive dyeing process. Integrated method showed water saving of 400% and thermal energy saving of 50% in comparison to the conventional method. Moreover, integration of all baths resulted into comparable effluent TDS, Tegewa scale rating, Color International De L'eclairage (CIE) whiteness, absorbency and lower color yield (K/S) without any adverse effect on color fastness of dyed towel. Thus, the integrated method has been shown to have improved eco-sustainability and economy.