Dyeing in catalase-treated bleaching baths

The conventional rinsing after bleaching to remove the residual hydrogen pe roxide, harmful to the dyes either in solution or on the fabric, was replac ed by enzymatic cleaning using catalases. The catalase-treated bleaching li quor was reused for dyeing. Though no hydrogen peroxide was detected after the enzymatic process, the bleaching bath composition caused unacceptable c olour changes on dyed fabrics. By varying the parameters of the dyeing proc ess - dye, salt, alkali and enzyme concentrations the colour difference cou ld be reduced significantly and a good dyeing result could be achieved.