突变T.fusca角质酶对涤纶织物表面水解作用研究

The effect of mutant T.fusca cutinase on surface hydrolysis of polyester fabric

本文研究突变T.fusca角质酶对涤纶织物表面水解作用,确定反应条件(酶质量浓度、时间、温度和pH值)、金属离子体积浓度对涤纶织物酶解产物释放量及其表面润湿性能的影响。结果表明,该突变T.fusca角质酶可以水解涤纶表面酯键,且主要的水解产物是对苯二甲酸。处理后的涤纶表面润湿性能得到改善,可实现由疏水到亲水的转变。突变T.fusca角质酶水解涤纶的适宜反应条件为:酶质量浓度20 U/g,反应时间48 h,反应温度60℃,pH值8。在此条件下,突变T.fusca角质酶与Ca^(2+)表现出明显的协同作用,水解产物释放量较单独用酶处理提高53%。

Polyester is favored by people because of its excellent properties such as high strength,excellent stretch resistance,and good wear resistance.However,due to the high degree of orientation of polyester and the lack of active groups,polyester exhibits some drawbacks influencing its wearing comforts,such as poor hydrophobicity and problems in dying,which also limits its application as a high-end material in the fields of medical treatment,food packaging,and electronic devices.To improve the hydrophilic property of polyester,technologies such as alkali reduction treatment,finishing agent coating,and enzymatic hydrolysis are used in the modification of polyester fabrics.From the point of view of economy and ecology,the enzyme-catalyzed reaction is carried out under mild reaction conditions without causing pollution,which can maintain the excellent mechanical properties of polyester.Therefore,enzyme-catalyzed polyester modification has broad prospects.Compared with lipase,cutinase lacks lid structure,and the active site is directly exposed to the solvent.This open and shallow active site allows better contact between the catalytic center and the substrate,and has better modification ability.Compared with chemical modification,there are still some shortcomings such as long reaction time and unsatisfactory catalysis effect in the reports on cutinase modification on the polyester.Therefore,improving the modification effect and shortening the treatment time are a new direction of current research.To improve the hydrophilicity of polyester,mutant T.fusca cutinase with excellent thermal stability was used to hydrolyze the surface of polyester,and the single factor variable test was applied to determine the suitable process conditions for enzymatic treatment of polyester:a cutinase dosage of 20 U/g,a reaction time of 48 h,a treatment temperature of 60℃,and a pH value of 8.Furthermore,the effects of Ca^(2+)volume concentration on the yield of TPA in the hydrolyzate were also studied.The result showed that the addition of Ca^(2+)can increase the yield of TPA by 53%compared with the single enzyme treatment,which strengthened the hydrolysis effect of the enzyme on polyester.Moreover,SEM showed that the fibers treated with cutinase had an obvious etching surface.At the same time,the surface wettability of the cutinase-treated fiber was also improved.The surface contact angle value of polyester changed from being hydrophobic to being hydrophilic.The dyeing effect of the fabric was improved,and the absorbance of the methylene blue dye solution decreased by 43%,indicating that the ester bond of polyester was hydrolyzed to generate hydrophilic groups.This is consistent with the results detected by HPLC,with the main hydrolysis product being TPA.Enzymatic modification has been widely used in textiles.However,due to the dense structure and high crystallinity of polyester,the catalytic effect of cutinase still needs to be further improved.The following measures can be taken to improve the effect of enzymatic modification of polyester.Firstly,it is recommended to develop new additives that can maintain the thermostable properties of enzymes to improve the tolerance of enzymes to reaction conditions.Secondly,it is suggested to use the synergistic effect of the multi-enzyme system to reduce the inhibition of BHET on enzymes and improve the hydrophilicity of polyester.Finally,it is proposed that the polyester should be pretreated to increase its specific surface area,improve the accessibility between enzymes and substrates,and reduce the catalytic reaction time.