Ultrasonic effect on the desizing efficiency of α-amylase on starch-sized cotton fabrics

Enzymatic desizing by alpha-amylase and ultrasound irradiation are the two important clean technologies in the textile industry. In the present work, with the aim of giving a further insight to the influence of ultrasound on alpha-amylase activity and its desizing efficiency, the ultrasound-based experiments were afforded in two ways: (i) step-wise treatment of alpha-amylase by ultrasound and then enzymatic desizing, as well as; (ii) simultaneous utilization of ultrasound and alpha-amylase for the desizing. By the step-wise strategy, it is found that the ultrasound has negative impact on the alpha-amylase activity using soluble starch as substrate. However, the sonicated alpha-amylase possesses higher desizing efficiency because there are higher hydrophobic interactions between sonicated alpha-amylase protein and starch-sized cotton and thus intensifies its catalytic activity. By the simultaneous procedure, the enhancement to desizing efficiency is more pronounced than that by the step-wise procedure. This can be attributed to comprehensive actions of several reasons such as more effective stirring/mixing mechanism, damages or changes to substrate, more effective catalysis to hydrolytic reactions and faster removal of loosened products from the fabric bulk. (C) 2013 Elsevier Ltd. All rights reserved.