A novel bio-technique using laccase enzyme in textile printing to fix natural dyes

Laccase enzyme has been used as a substitute of harmful mordants in fixation of three different types of flavonoids (natural dyes), namely rutin, morin and quercetin, in printing of fabrics and the optimum conditions to achieve the best results are determined. The effects of enzyme concentration, pH of printing paste, treatment time and temperature as well as the nature of the printed substrate on the properties of printed goods expressed as K/S and overall fastness properties have been thoroughly investigated. The results show that the optimum conditions for using rutin in printing cotton fabrics are enzyme concentration 60g/kg printing paste, pH 4.5, treatment time 60 min and temperature 60C. Laccase undergoes enzymatic oxidative polymerization of flavonoids giving the coloured pigment. It is also observed that with this technique, the above three kinds of flavonoids could be used for printing all kinds of fabrics, as in case of pigments, with very good to excellent colour fastness. However, the colour strength of the printed goods depends on the concentration of enzyme, pH of printing paste, treatment time, temperature of treatment, fixation conditions, nature of flavanoids used, and nature of printed fabric.