Enzymatic pre-treatment of cotton. Part 2: Peroxide generation in desizing liquor and bleaching

Abstract

The objective of this study was to utilise desizing liquors of starch-sized fabrics using glucoseoxidase enzymes for bleach to produce hydrogen peroxide front glucose units of the starch removed; glucoseoxidase enzymes are efficient only at high glucose doses. In the first part of this paper, glucose generation in a desizing bath was discussed and an optimum recipe was obtained with an amyloglucodidase/pullanase mixture enzyme. In this study, process optimisation for the glucose oxidase enzyme was undertaken in order to generate hydrogen peroxide in the desizing liquor and then bleaching with the peroxide generated. Results indicated that sufficient hydrogen peroxide, about 800 mg l(-1), could be generated to perform successful enzymatic bleaching; however, the bleaching was compatible with the conventional peroxide type only in the alkali pH range. The maximum whiteness obtained by enzymatic treatment was 73.8 Stensby degree, whereas the whiteness of the conventionally treated fabric was 79.4 Stensby degree.