Research On The Interaction Of Bisphenol A And Bisphenol S With Hydrolase In Sludge

Bisphenol compounds(such as BPA and BPS)are widely used in the production of electronic equipment,food packaging,dental sealants,baby bottles,polycarbonate plastics and thermosensitive paper.Due to medium water solubility and low vapor pressure,bisphenol compounds can be discharged to the environment in a variety of ways,resulting in its widespread detection in the matrix of air,water,soil,sediment,waste sludge,indoor dust,human tissue,household waste paper,blood and urine.Bisphenol compounds are endocrine disruptors and have acute toxicity,genotoxicity,estrogenic activity and hard-to-degrade properties.Studies have shown that bisphenol A can not only affect the development and stability of human embryos,but also damage the behavior of the prostate and brain and infants and young children.Molecular and cytotoxicity studies of bisphenol S indicate that it can not only induce DNA damage,but also irreversibly bind serum albumin,pepsin and trypsin,resulting in decreased enzyme activity.Therefore,this study selected bisphenol A and bisphenol S as the research subjects.Firstly,the effect of bisphenols on the hydrolysis of sludge was studied.Secondly,the interaction between bisphenol compounds and sludge hydrolase(a-amylase)was analyzed.Finally,exploring the removal and removal mechanism of bisphenol compounds extracted from sludge and reed sediment by multi-enzymes.The specific research content is as follows:Part I:Study the effect of bisphenol A on the hydrolysis of sludge and the interaction between bisphenol A and ?-amylase.Firstly,three-dimensional fluorescence technology was used to analyze the changes in the composition and concentration of soluble organic pollutants in sludge to characterize the effect of bisphenol A on the hydrolysis of sludge.Secondly,the interaction mechanism between a-amylase and bisphenol A was studied from the molecular level using spectroscopy,isothermal titration calorimetry,molecular simulation,and enzyme activity experiments.Experiments showed that bisphenol A changed the secondary structure of the a-amylase and the microenvironment of amino acid residues in the a-amylase.Molecular docking studies and ITC results indicated the presence of hydrophobic and hydrogen bonds in the interaction between bisphenol A and a-amylase.Based on the above analysis and the enzyme activity test,it could be concluded that the exposure of bisphenol A affected the activity of the hydrolase(?-amylase)and thus affected the hydrolysis of the sludge.Part ?:Study the effect of bisphenol S on the hydrolysis of sludge and the interaction between bisphenol S and a-amylase.Results showed that BPS further inhibited sludge hydrolysis by inhibiting the activity of a-amylase.And BPS interacted with a-amylase by hydrophobic bond in the activity region of a-amylase.This interaction not only caused an unfolding skeleton structure of a-amylase and a less hydrophobic microenvironment of tyrosine and tryptophan residues,but also led to a specific fluorophore quenching involving static and dynamic type.Part ?:Dissection of the removal of bisphenol S in aqueous solution with multi-enzymes from waste sludge and reed sediment.Firstly,the multi-enzymes were extracted from the sludge and reed sediments using ultrasonication and centrifugation,and then the complex enzyme was characterized by gel electrophoresis,three-dimensional fluorescence and Coomassie brilliant blue.Finally,the biodegradation of bisphenol S by.multi-enzymes at different temperatures(298K,310K and 328K)was studied,and the removal mechanism of bisphenol S by the multi-enzymes was analyzed by liquid chromatography-mass spectrometry/mass spectrometry(LC-MS/MS).The results showed that bisphenol S could be removed by the multi-enzymes in the sludge and reed sediment.The removal rate was the highest at 328 K,and the removal mechanism was enzymatic hydrolysis and biological flocculation.The results of this study can not only provide a reference for the biologicalremoval of bisphenol compounds,but also provide an economical and simple method and approach for the utilization of sludge.