The effects of ozone on the enzyme activity and bleaching effect of laccase have been examined in this study. Laccase treatment at 40°C did not increase the whiteness of the fabric alone. However, ozone feed into the bleaching bath prepared with laccase increased the Stensby whiteness degree of the fabric from 61 to 69, ozonation alone resulted in a whiteness degree of 71. Ozone decreased the enzyme activity because of its oxidative effect. A post bleaching process with hydrogen peroxide was conducted to improve the whiteness degrees of the treated fabrics, and this resulted in increases in the whiteness degrees. The whiteness degree of the sample treated with ozone increased upto 83 (stensby) after post bleaching and reached the whiteness value of the conventionally bleached sample.
