Preparation Of Immobilized Protease And Its Application On Shrink-Resist Finishing Of Wool Fabrics

Taking advantages of controlled product purity,stability and reusability,immobilized enzyme technique has been widely used in fields of bioengineering,chemistry,foodstuff industry, medicine,etc.But in textile industry,immobilized enzyme is not widely used,especially on shrink-resist finishing,chlorine/Hercosett and protease methods are used more.In this paper,two immobilized protease were prepared with magnetic chitosan microspheres and Eudragit S-100 as carriers,and also some research on optimal conditions of immobilization,changes in properties, kinetics parameters and application on shrink-resist finishing of wool fabrics were studied.In this paper,As a carrier magnetic chitosan microspheres were prepared by the suspension cross-linking technique,immobilized protease was prepared with glutaraldehyde as cross-linking agent.The conditions of immobilization were optimized by single-actor experiment,and the stability,reusability,kinetics parameters of immobilized protease and its application on shrink-resist finishing were also studied.The results were shown as follows:magnetic chitosan microspheres were of core-multisheil type,weak magnetism,size was about 30-50μm.The optimum condition of magnetic immobilized protease shows that when concentration of EDC was 0.25%(w/v),glutaraldehyde was 2.0%(v/v),protease(pH=7.5) was 0.4%(v/v),temperature was 40℃,immobilization time was 90min,the ratio of immobilization and activity recovery of the immobilized enzyme reached 82.4%and 65.8%respectively.Compared with free enzyme,the magnetic immobilized protease showed more desirable acid and alkali resistance property, stability of storage,reusable,and its K_m value was 2.76 times larger than that of free one.The magnetic immobilized protease was used on shrink-resist finishing of wool fabrics and its treatment condition was optimized by orthogonal experiment.The treatment results of magnetic immobilized protease(or free one) showed that the shrinkage rate was 7.1%(6.9%).the weight loss percentage was 6.4%(11.7%) and the strength loss percentage was 8.2%(19.1%).As soluble-insoluble macromolecule Eudragit S-100 a carrier,soluble-insoluble immobilized protease was also prepared which the resolvability could be change at different pH value.The preparation conditions were optimized by single-actor experiment,and its stability,reusability kinetics parameters and application on shrink-resist finishing were also studied.The optimum condition of immobilized protease shows that when concentration of Eudragit S-100 was 2.0%(w/v),EDC was 0.2%(w/v),protease(pH=7.5) was 1.0%(v/v),immobilization temperature was 30℃,immobilization time was 90min,the ratio of immobilization and activity recovery of the immobilized enzyme reached 89.6%and 80.7%respectively.Compared with free enzyme,the soluble-insoluble immobilized protease showed more desirable acid and alkali resistance property and stability of storage,reusable,and its K_m value was 1.94 times larger than free one.The soluble-insoluble immobilized protease was used on shrink-resist finishing of wool fabrics and its treatment condition was optimized by orthogonai experiment.The results of soluble-insoluble protease(or free one) were that the shrinkage rate was 6.4%(6.9%),the weight loss percentage was 9.1%(11.7%) and the strength loss percentage was 7.8%(19.1%).