2.6. Enzyme stability during cotton bleaching under ultrasound
In order to evaluate the stability and efficiency of laccase micro-emulsions, desized fabrics were pretreated in the ultrasound bath sonicator with fixed frequency 45 kHz and power intensity at 120 W. One sample was incubated with 2 U/mL of free laccase and other with 2 U/mL of laccase micro-emulsion, in 0.1 M acetate buffer pH 5, at 50◦C during 30 min. The activity was determined as mentioned in Section 2.4. Cotton samples were further washed with distilled water at 80◦C and dry at room temperature. The pretreated cotton fabrics were bleached afterwards following the recipe: 1 g/L anti-wrinkle, 0.5% wetting agent, 1.5 g/L sequestrant, 4 g/L NaOH, 8 g/L H2O2, 3 g/L equalizer,