Study On Optimizing The Activity Of Chitin Deacetylase

Size not only relates to the quality and efficiency of production,but also to the zoology and environment-ptotecting of consumption and finishing.Size in sizng pollutes environment in two means.The first,the modulating of size,the left size and waste water including size.The second,the undisposed waste water in retiring size process,in addition,some size substance left on fabric after retiring size and boiling is disadvantageous for people.So as for weaving enterprises,it is important to use green environment-ptotecting size in sizing for durative development in textile industry and environment-ptotecting. Chitin and its ramification is legalized as green macromolecule material.At present,chitosan is usually used as chitin size. Chitin size owns many excellent properties,for instance,it can form strong film,has good abrasion resistance and also good agglutination and appetencies for special type fiber.Besides,it has good biodegradation and biologic activity,eminent antibacterial and bacteriostasic activity.This natural maeromolecular polymers accord with the require to protect environment.Its excellent performance makes it will be empoldered as new green size.However,chitin's steay chemical structure restricts its water solubility.At present,the chitosan is prepared by chemical methods.The molecular weight of chitosan produced by those methods is pockety,uniformity is tinpot,and it's easy to wastes energy sources and pollutes environment.At the same time,the hydrolyzing methods with enzyme don't make any accessory reactions,the reaction conditions are gentle,and it's easy to control technics.So it is a perfect hydrolyzing method.Therefore,it is very meaningful to study how to use enzyme to improve the water solubility of the size.The paper studies the method of preparing chitosan with chitin deacetylase(CDA),and also optimizing the selected enzyme based on other people's research to improve the activity of chitin deacetylase(CDA) and the degree of deacetylation of chitin ulteriorly.Based on the resumption training of Aspergillus nidulans that can produces chitin deacetylase(CDA),the morphology of bacteria is observed.And through the liquid fermentation,the CDA can be brought.In order to improve the activity of chitin deacetylase(CDA),the training conditions such as training time,temperature,pH value,the concentration of carbon(soluble chitosan) and nitrogen sources(yeast),the addition of metal ions(Co²⁺) and the inoculation quantity are researched.By means of singer-factor experiments and orthogonal design experiment,the best liquid fermentation training conditions are educed:When the training time of 96 hours,the initial pH value of 6.5,the fermentation temperature of 31℃,the concentration of carbon and nitrogen sources are2% and 2%,the addition of metal ions and the inoculation quantity are 0.01mol/L,and the inoculation quantity is 6%,the activity of enzyme that Aspergillus nidulans prodeces could reach 13.68U/mL。The paper also studies the deacetylation effect of chitin deacetylase after acting on degraded chitin.The enzyme liquid is distilled after fermented,then it acts with degraded chitin.The craft conditions such as pH value,acting time, temperature are reviewed.Taking the degree of deacetylation as judging index,orthogonal design experiment is adopted,the optimal process conditions are identified.The chitosan product with degree of deacetylation 67.78%could be produced.