Researchers investigated the effects of dyeing cotton with enzyme treated bleaching effluents. An experiment dyed bleached woven cotton fabrics with C.I. Reactive Blue 198 at a 20:1 liquor ratio with three repetitions. Enzyme treatment with catalase removed hydrogen peroxide from the bleach bath. CIELab color space at standard illuminant D(65) determined the color differences of the fabrics. A Spex Industries Fluorolog-2 fluorescence spectrophotometer determined the emission spectra. The proportion of dye in the initial bath and the remaining dye determined the percentage of exhaustion and fixation. Cooling the bleach bath prevented inactivation of the catalase. The enzyme treatment removed the hydrogen peroxide, but the bleach effluent still resulted in unacceptable color changes, possibly due to the thermal unfolding and denaturation of the protein at high temperatures. Adjusting the dye, salt, alkali, and enzyme concentration reduced the level of color differences. 16 refs.