Laccase-catalyzed in-situ dyeing of wool fabric

Compared to the traditional dyeing processes using synthetic dyes, biological dyeing method has a bright future in the textile industry due to their advantages of environmentally-friendly and milder processing conditions. Biological dyeing involves the catalysis of phenolic monomers by oxidoreductases, such as laccase, to form the colorful polymers used for dyeing. In this study, wool fabrics were treated with laccase/phenol via a one-or two-step treatment, and polymers synthesized in-situ were used to dye wool fabrics. The K/S values of the wool fabrics were evaluated under different treatment conditions, including the dosages of laccase and dye precursor, temperature, pH, mediator type, and mechanical agitation. The surface of wool fibers was examined using a scanning electron microscope (SEM). The results showed that the dyeing effect of the wool fabric samples using the single step processing method of in-situ color synthesis and fabric dyeing was better than those dyed using the two-step methods of color synthesis and fabric dyeing under the same conditions. The color depth of the dyed wool fabrics increased gradually with increasing concentration of laccase, and also depended on other process parameters, such as dosage of catechol, temperature, and pH. Moreover, addition of mediators and adjustment of mechanical agitation also improved the color depth of the wool fabrics which were dyed in-situ.