Study On The Effect Of Tween 80 On The Degradation Of Anthracene By Laccase-Medium System

The ecological and health problems caused by PAHs have been around for a long time,and various measures including physical,chemical,biological and their combined technologies have been tried to cope with PAHs in the environment and good progress has been made.As a kind of green biocatalysts,laccase has been paid more and more attention.Since most redox potential of laccase is low,it is necessary to add a medium to biocatalytic degradation of PAHs;PAHs have a strong hydrophobicity,and usually related studies will add non-ionic surfactants such as Tween 80 and Tween 20 to increase their solubility.After adding surfactant,the laccase medium system?LMS?becomes more complex,and thanks to the development of micellar enzymology,most of the attention is focused on the changes in laccase conformation and activity caused by the physical forces between surfactants and laccase,and few people pay attention to the effects of chemical changes in surfactants during enzymatic reaction.Based on this,this paper has carried out a series of studies on the possible influencing factors of LMS-PAHs after adding surfactant,and discusses its mechanism from the addition of non-ionic surfactant Tween 80,the change of the solubility of anthracene,the change of laccase activity and the change of the kinetic parameters of enzyme-promoting reaction.Preliminary findings indicate that:?1?Using GC/MS to analyze the products of LMS-HOBT that add and do not add Tween 80/Tween 20 to degrade anthracene and Tween 80/Tween 20 alone under the same experimental conditions as blank contrast,it is found that the main intermediate conversion product of anthracene is anthraquinone,and a large number of oxidation products of surfactants,such as aldehydes and esters,have been detected.?2?The degradation of anthracene by LMS-HOBT/PCA added Tween 80 conforms to the pseudo first-order kinetics,and the kinetic parameters k(h^-1)and the corresponding half-life(T_1/2)decreases as the concentration of Tween 80 increases.?3?In LMS-HOBT of the addition of Tween 80/Tween 20,the hydrogen in the Tween80 structure?ether oxygen bond and carbon-carbon double bond?-CH?and Tween 20 structure?ether oxygen bond?-CH?can be seized by LMS,resulting in Tween 80/Tween 20 degradation to produce a large number of reactive oxygen free radicals?ROS?.These ROS will continue to oxidize Tween 80/Tween 20 and convert anthracene at the same time;it is speculated that when enzyme activity is measured in LMS-HOBT/PCA containing ether oxygen bond and carbon double bond surfactant,the presence of ROS causes non-enzymatic oxidation of the substrate?such as ABTS?,which leads to the"increase"of laccase activities.?4?Adding Tween 80 to LMS-HOBT/PCA can promote the degradation of anthracene,and the concentration of Tween 80 is closely related to the degradation effect,but there is little correlation with the solubility of anthracene in Tween 80 solution.