Enzymatic-Synthesized Peracetic Acid Catalyzed By Perhydrolase Or Perhydrolase Coupled With Glucose Oxidase

This paper explored the enzymatic-synthesized of peracetic acid and its application.Peracetic acid could be used as a strong oxidant,fungicide and sterilizer.It was an important chemical raw material which was widely used in many fields such as industrial and agricultural production.Traditional chemical synthesis processes had serious problems including production safety and products quality instability.As a green processing technology,enzymatic-synthesized of peracetic acid process had the advantages of safe and controllable production,stable quality and so on.In this paper,(1)the feasibility of in-situ oxidative treatment of pulp cellulose with peracetic acid produced by perhydrolase was evaluated firstly;(2)On this basis,Synthetic kinetic constant of different catalyzed substrates by perhydrolase was determined.The experimental results showed that whether ethyl acetate,propylene glycol diacetate or triacetin was used to promote the synthesis reaction to peracetic acid,high concentration of hydrogen peroxide was required in the system;(3)In order to solve the problem that the concentration of hydrogen peroxide caused the denaturation of the enzyme protein and affected the stability of the reaction system.This study explored and evaluated the feasibility of the double-enzyme catalyzed tandem reaction of glucose oxidase-perhydrolase to synthesize peracetic acid;and the tandem synthesis of peracetic acid catalyzed by double enzyme and the in-situ oxidation of peracetic acid to the dyeing process.In order to completely solve the negative factors affecting the stability of the system in the enzymatic-synthesized of peracetic acid.The specific experimental results are as follows:1.The peracetic acid catalyzed by perhydrolase could effectively treat cellulose in situ.The experimental results showed that the pulp cellulose treated by peracetic acid synthesized by perhydrolase had high separation of fiber bundles and increased whiteness of cellulose.The peracetic acid-treated cellulose was modified by methyltrimethoxysilane.Below,the maximum oil absorption rate was 23.7%higher than that of cellulose without peracetic acid treatment.2.Determination of the kinetic constants of perhydrolase for three substrates by colorimetric method:Km,Vmax,and kcat/Km for ethyl acetate at a constant hydrogenperoxide concentration of 10 mmol/L in the reaction system.They were:122.5 mmol L-1,42.5?mol·mg-1·min-1 and 9.7 L·mmol-1·min-1;the Km,Vmax,and kcat/Km for propyleneglycol diacetate were:5.17 mmol·L-1,62.14?mol mg-1·min-1and 336.86 L-mmol-1·min-1;Km,Vma and Kcat/Km for triacetin were 6.29 mmol·L-1,respectively,42.85 umol·mg-1·min-1and 190.80 L·mmol-1·min-1.Based on the concentration of the estersubstrate at a reaction rate of 0.89 Vmax,the enzymatic kinetic constants of hydrogen peroxide at this concentration(ester)were determined respectively:when the synthesis substrate was ethyl acetate,the Km and kcat values of hydrogen were 38.17 mmol·L-1and 5.95×103 min-1,respectively.When the synthesis substrate was propylene glycol diacetate,Km and Kcat were 36.84 mmol·L-1and 8.38×103 min-1,respectively.When thesynthesis substrate is triacetin,Km and Kcat are 19.59 mmol·L-1 and 3.54×1O3 min-1,respectively.3.,The Km,Vmax,Kcat/Km of glucose oxidase were 28.31 mmol·L-1,87.36?mol mg-1·min-1,1.67×104 min-1and 592.48 L·mmol-1·min-1,respectively.The glucoseconcentration was 200 mmol/L,the ethyl acetate concentration was 1000 mmol/L,and the glucose oxidase-perhydrolase activity was 10:1(perhydrolase enzyme 5.35 mU/mL).Hydrolysis enzyme coupling reaction system showed a good linear relationship.Using this tandem reaction,printing and dyeing wastewater with RBBR as a model could be efficiently treated,and the decolorization rate could reach 90.27%.