Chiral Degradation Of Triadimenol By Microorganism

With the continuous development of agricultural economy,the amount and types of pesticides are increasing year by year,in which the increasing of the amount and types of chiral pesticides is more significant.The proportion of the use of chiral pesticides has exceeded 40%.The results show that when triadimenol is applied in nature,enantiomers of chiral pesticides often show different digestion and orientation in the environment and enantiomer transformation can not be ignored.This difference may be caused by the metabolism of environmental microorganisms.Through the study of degradation characteristics of triadimenol pesticides at the enantiomer level by soil degradation and high-efficiency strain degradation,the aim is to provide theoretical and experimental basis for pesticide residues at the enantiomer level,which has certain significance for the environmental behavior of chiral pesticides and the assessment of their environmental risk.In this experiment,two kinds of triazole pesticides of triadimenol standard and triadimenol industrial products are selected to study their selective degradation behavior in soil and under the action of selected dominant strains.The results are as follows:1)Degradation Behavior of Triadimenol Standard in Different SoilsDegradation behavior of triadimenol standard in Handan loess and Changsha laterite is studied.The degradation half-lives of triadimenol standard are 57.28 d and 47.15 d,respectively.During the degradation process,both soils show obvious transformation from triadimenol-A to triadimenol-B.Through sterilization control test,the degradation behavior of triadimenol standard in soil is mainly caused by soil microorganisms.2)Enantioselective Behavior of Triadimenol Standards in Different SoilsThe enantioselective degradation of triadimenol-A and triadimenol-B exists in soils with different properties.In Handan loess,the degradation of triadimenol-A is 1S,2Rtriadimenol is faster than 1R,2S-triadimenol,and 1R,2R-triadimenol is faster than 1S,2S-triadimenol.In Changsha laterite,the ER value of triadimenol-A remains basically unchanged,indicating that there is no enantioselectivity in soil degradation process;triadimenol-B shows that 1R,2R-triadimenol degradation faster than 1S,2S-triadimenol.3)Screening,Identification and Enantioselective Degradation of Microorganisms Degrading Triadimenol Industrial ProductsThe degradation of triadimenol by strains H-1,H-2,C-1 and C-2 screened from Handan loess and Changsha laterite is systematically studied.Through the analysis of the selective degradation characteristics of a single strain to triadimenol industrial products,it is found that the four dominant strains have isomer selectivity in the degradation process;and all of them preferentially degrade triadimenol-B;H-1 and C-2 have enantioselective degradation to triadimenol-B;1S,2S-triadimenol degradation is faster than 1R,2Rtriadimenol.