Study On The Degradation And Kinetics Of Bisphenol A And Bisphenol E By Trametes Versicolor Laccase

Bisphenol A,a typical environmental endocrine disruptor,enters the body through various pathways,interferes with the action of normal hormones,impairs the function of living body such as reproduction,nerves,and immune system,and has strong cancer-causing effects,teratogenic and mutagenic effects on living organisms.With the enhancement of human awareness of environmental governance,they began to look for alternatives to bisphenol A,and bisphenol E gradually began to appear in industrial synthetic raw materials,but its biological toxicity was no less than that of bisphenol A.Therefore,the environmental problems of the treatment of bisphenol compounds need to be further solved.Laccase(EC1.10.3.2)is a polyphenol oxidase containing copper ions.It has a wide range of degradation of substrates and can degrade a variety of environmental harmful pollutants.Currently,the biological method of using laccase to treat environmental pollution is widely used because its green is not easy to cause secondary pollution.This article studied the degradation of bisphenol A and bisphenol E by Trametes versicolor pure laccase and Trametes versicolor crude enzyme solution.,and the influence of various factors on the degradation effect was investigated.The research results are as follows:1.Molecular docking of Trametes versicolor laccase with bisphenol A.The calculated binding free energy of laccase and bisphenol A was-7.25 kcal/mol,and the bisphenol E was-6.91 kcal/mol.The results showed that the reaction of Trametes versicolor laccase with bisphenol A and E can be performed spontaneously.2.Study on the degradation effect of Trametes versicolor pure laccase on bisphenol A and bisphenol E,and explore the influence of reaction time,temperature,pH of the reaction system,and substrate concentration on its degradation effect.The results showed that the influence of various factors was significant.The optimal results were obtained at the reaction time of 12 h,temperature 27.5°C,pH 5.5,and the substrate concentration of 5 mg/L.The degradation rates of bisphenol A and bisphenol E were 98.82% and 94.17% in the above conditions.3.The main products of degradation of bisphenol A by Trametes versicolor pure laccase enzyme are ethylbenzene,p-xylene,cyclohexanone,1-methyl-4-isopropenyl-2-cyclohexenol.The derivation of the reaction mechanism was performed with this product.4.Using the Trametes versicolor pure laccase enzyme to study the kinetics of substrate degradation at different concentrations,the results showed that when the initial substrate concentration was 5 mg/L,the reaction followed a first-order kinetic equation.As the initial concentration of substrate increased,the amount of laccase enzyme reacted was no more than the substrate,and the reaction was a mixed-grade kinetic reaction.5.Degradation of bisphenol A and bisphenol E by culturing crude enzyme solution of Trametes versicolor laccase,and exploring the influence of reaction time,temperature,reaction system pH,substrate concentration on its degradation effect,and then optimize the response surface.The optimized conditions for bisphenol A were as follows: pH 5.20,temperature 44.6°C,and the substrate concentration 5 mg/L;the bisphenol E was: pH 5.17,temperature 44.9°C,and the substrate concentration 5 mg/L.After 3 hours of reaction,the degradation rates were 97.68% and 97.96%,respectively.