Complete enzymatic pre-treatment of cotton fabric with incorporated bleach activator

The feasibility of a complete enzymatic one-bath pre-treatment of the cotton fabric at low temperature was investigated in this study. The cotton fabric was enzymatically desized, scoured and bleached with an enzyme mixture of starch-degrading enzymes, pectinases and glucose oxidases, respectively. Starch-degrading enzymes hydrolyzed the sizing agent into glucose. Glucose oxidases catalyzed the oxidation of β-D-glucose to D-glucono-ω-lactone and simultaneously generated hydrogen peroxide. The desizing and hydrogen peroxide generation each took one hour. For bleaching, hydrogen peroxide was converted into peracetic acid by incorporating the bleach activator tetra acetyl ethylene diamine (TAED). Bleaching took place at 50°C and neutral pH, where peracetic acid is most effective. Pectinases were added into the pre-treatment bath to remove pectins from fibers and improve their wettability. Whiteness values, water absorbency, polymerization degree and tenacity at maximum load were measured on pre-treated samples. The total organic carbon, pH and biodegradability were measured on residual pre-treatment baths. It was established that hydrogen peroxide can be efficiently enzymatically produced from the sizing agent and converted with TAED to form peracetic acid to bleach the cotton fabric. Cotton fabrics with a medium degree of whiteness, W = 51, and good water absorbency can be obtained at low water and energy consumption.