The Disinfection Characteristics Of Tea Polyphenols And Their Mechanism Of Action On E.coli

To solve the health problems of urban drinking water,it is necessary to research and develop new disinfectants to ensure the disinfection effect and the safety of water quality.After comparing the traditional chlorine disinfectant,the tea polyphenols disinfection has the advantages that many chlorine disinfectants do not have.The green health and the characteristics of not producing the disinfection by-products are particularly important to improve the safety of disinfection.Traditional chlorination is a complex process of chemical bioreaction,and its reaction starts from chlorine in water plant until the transportation of pipe water to the user.Similarly,if tea polyphenols are sterilized,it will react and decay in the pipe network.The attenuation of disinfectants will affect the effect of disinfection,so we should carry out relevant research on the attenuation of tea polyphenols,and the effect of tea polyphenols on the biological stability of water is not clear,so we need to further study the relationship between tea polyphenols and biological stability of water.There are many studies on the bacteriostasis mechanism of tea polyphenols in the application of food and medicine.The research on the mechanism of tea polyphenols in water disinfection is still a blank.Therefore,it is necessary to study the mechanism of the effect of tea polyphenols on the bacteria in water according to the water quality conditions,and provide the basis for the application of tea polyphenols.The effect of the initial concentration of EGCG,pH and light on the attenuation of EGCG was studied by the oxidation polymerization of tea polyphenols.The attenuation coefficient equation under the influence factors was obtained.The experimental results showed that the initial concentration of EGCG was 100mg/L,pH was 10,and the rate of oxidation polymerization of tea polyphenols was the fastest,the attenuation coefficient is the largest,and the rate of attenuation is the greatest.At the same time,the initial concentration of EGCG is in the range of 100mg/L~400mg/L,and the greater the initial concentration of EGCG,the slower the attenuation rate.the higher the pH is in the range of 4~10,the faster the decline and deceleration rate of pH;the attenuation rate of light is faster than the light avoidance.A prediction model of attenuation coefficient is obtained based on the attenuation coefficient relationship of all factors.Biodegradable organic carbon(BDOC)was used as an index to evaluate the biological stability of water,and the concentration of BDOC,total bacteria,TOC and EGCG in water was analyzed.The results showed that adding EGCG would affect the change of BDOCcontent in water,and the concentration of addition could also affect the degree of BDOC change.There is a certain correlation between the deceleration rate of EGCG and the formation rate of BDOC.It is possible that the tea polyphenols have covalent or non covalent reactions with the bacterial proteins in the bacteria.The organic matter generated by the polyphenols has lost the activity of tea polyphenols,which leads to the increase of biodegradable dissolved organic carbon;Or after the action of tea polyphenols,the bacterial body breaks down,the content of the bacteria is dissolved and the BDOC increases.It is also possible that the excessive BDOC in the raw water causes the effect on the subsequent addition of the tea polyphenols.It is suggested that the pre added ultrafiltration can be used to remove the BDOC in the raw water,and the biological stability of the water can be improved by controlling the attenuation of the polyphenol.The orthogonal test is used to study the action mechanism of tea polyphenols on E.coli,and three factors that could affect the oxidation polymerization of tea polyphenols were selected,and the experiment was carried out in combination with the possible working conditions of the water to determine the three level.The results showed that under the condition of adding EGCG/EGC60mg/L,buffer pH8.0 and reaction temperature 25 centigrade,the effect on the cell membrane of Escherichia coli was the strongest.Tea polyphenols can depolarize the membrane of Escherichia coli and the membrane ion Exodus,increase the permeability of the membrane and outer membrane,and exosmosis of water soluble substances;it can inhibit the respiration of Escherichia coli and inhibit its physiological metabolic activity.And in the factors affecting the mechanism of Escherichia coli,the higher the concentration of EGCG/EGC,the range of pH 6.8~8.0,and the temperature range 5degrees centigrade,the greater the concentration,the greater the pH,the higher the temperature,the stronger the inhibitory effect of the Escherichia coli,and the inhibition of EGCG is stronger than that of EGC.