Enzymatic Desizing of Polyvinyl Alcohol from Cotton Fabrics

Abstract

Enzymatic degradation of polyvinyl alcohol (PVA) was used for the desizing of cotton fabrics. A mixture of two different PVA-degrading enzyme activities, including PVA oxidizing, was partially purified from the culture filtrate of a PVA-degrading mixed culture by ionic exchange chromatography. Optimum conditions for PVA-degradation by using this enzyme mixture were pH 8·0 and temperatures ranging from 30°C to 55°C. Cotton fabrics sized with a PVA solution (25 g dm−3) were desized with the enzyme mixture after a 1 h treatment at 30°C and pH 8·0. In this case, similar amounts of residual PVA in fabrics were detected in comparison with the conventional desizing process which uses hot water (80°C, 30 min). Minimum amounts of residual PVA were found when the enzymatic desizing time was extended to 6 h. Also, the PVA content in the liquid waste from the enzymatic desizing carried out during 4 h was negligible with a 7·4-fold increase in the biochemical oxygen demand as compared with the initial value. © 1997 SCI.