Bio-scouring process optimization of wool fiber and wastewater utilization

Abstract

This paper is aimed at developing a method to optimize the wool‐scouring process with bio‐enzymes of Bacillus subtilis and Candida lipolytica. Good experimental conditions, first determined by single factor test, were the ratio of B. subtilis to C. lipolytica 1:4, temperature 40°C, pH 7.0, enzyme consumption 6%, bath ratio 1:35, and time 16 h. Based on these conditions, the Plackett–Burman design (P–B design) was used to determine the main influencing factors such as bath ratio, temperature, and time for enzymatic scouring. Then, a Response Surface Method (RSM) was used to optimize these factors, and the optimum parameters were solved with the quadratic regression equation: bath ratio 1:33.28, temperature 40.44°C, and time 18.11 h. Under these optimum conditions, the residual fat content in bio‐scoured wool was 0.75%. Furthermore, the wool surface was smoother and cleaner than the non‐optimized one. In addition, the lanolin was reclaimed as a valuable material in industry by centrifugation from wastewater, and it could reduce the content of organic substance to decrease the environmental pollution. Moreover, the residual lanolin, perspiration, dung, chaffy, short wool, and silt were utilized to make ecological organic fertilizer by compost treating. It could achieve the complex utilization of bio‐scouring wastewater.