Optimizing bioscouring condition of cotton knitted fabrics with an alkaline pectinase from Bacillus subtilis WSHB04-02 by using response surface methodology

This present study was undertaken to find optimum conditions of pH, temperature, incubation time and enzyme concentration for bioscouring of cotton knitted fabrics with an alkaline pectinase isolated from Bacillus subtilis WSHB04-02 by use of response surface methodology (RSM). A central composite design was used as an experimental design for the analysis of the allocation of treatment combination. A second-order polynomial regression model was fitted and was found adequate with a determination coefficient R2 of 0.9844 (P < 0.001). The effect of pH was the most significant factor influencing cotton bioscouring and no significant interactions between different factors were found. Estimated optimum parameters were as follows: pH 9.1, temperature 57 °C, incubation time 1.25 h and pectinase concentration 1.0 g/l. Under these conditions, a desired pectin removal percentage companied with adequate wettability was reached. In addition, a boiling water pretreatment of 30 min before enzymatic scouring was found to be useful for subsequent pectinase degradation due to the improvement of the accessibility of pectinase to the pectins in cotton fibers.