Screening And Identification Of Cypermethrin And 3-Phenoxybenzoate Acid Degradaing "Gloden Flower Fungi" From Fuzhuan Tea And Its Dagradation Characteristic

Pyrethroid insecticides (PY) has been widely used in agricultural production, and it has some potential for development. However, its degradation is difficult under natural conditions and can accumulate in the environment and remain in agricultural produces for a long time, thus resulting in severe damages to environment and human healthy. Moreover, most pyrethroid insecticides also produces other pollutants in the degradation process, cause secondary pollution of the environment, which can seriously affect the sustainable development of modern agriculture. Microbial degradation is an green and efficient method way to degradate various pesticides and their intermediates It has become a hotspot on residues degrading.Based on the current incomplete researches on the source of the cypermethrin-degrading strain, single degrading pathway of CY and risk of CY residus degraded by microorganism. So adopting fuzhuan tea as bacteria source, and screening"golden flower fungi" which has the ability to degrade CY and 3-phenoxybenzoate acid. The degradation character and the pathway of CY by strain was studied and proposed to provide reference for the further research and practicl application of degrading strain.1. Screening of CY-degradative "golden flower fungi" and its appraisal. Adopting fuzhuan tea as bacteria source, twenty strains of "golden flower fungi" were screened. The strain ET1 could degrade 51.4% of CY in the PD medium (50mg/L) in 7d, and the strain ET1 could completely degrade 100mg/L 3-PBA in the PD medium in 7d, which was isolated from the fuzhuan tea. According to morphological characteristics and ITS sequences analysis (GenBank Accession No. KF317836), strain ET1 was identified as Eurotium cristatum.2. The characterization of Eurotium cristatum ET1 to CY and 3-PBA. Kinetic research indicated that the degradation of CY and 3-PBA by strain ET1 could be described by a first-order kinetics model. The degradation half-life of CY was 3.38 to 11.24d over a certain range of CY concentration, temperature and pH. the concentration of CY found influencing the reaction rate obviously but the pH and temperature had little effect on reaction rate.The degradation half-life of 3-PBA, mush shorter than natural half-life, was 1.71 to 3.23d over a certain range of 3-PBA concentration, temperature and pH. The pH were found influencing the reaction rate obviously but the concentration of 3-PBA and temperature had little effect on reaction rate.3. Pathway for degrading of CY by Eurotium cristatum ET1. According to the HPLC method to detect the characteristic of CY progressively, and GC-MS confirmation of intermediate degradation product, to inferre the pathway of 3-PBA for degrading of CY, and the pathway for more degrading for 3-PBA:effect of esterase on making CY hydrolysis of permethrin and a-cyano-3-Phenoxybenzalcohol; The latter spontaneous oxidized to 3-Phenoxybenzaldehyde, and further oxidized to 3-Phenoxybenzoic Acid; Effect of dioxygenase on making 3-Phenoxybenzoic Acid wre oxidized to phenol and protocatechuic acid; Protocatechuic acid further oxidized to straight-chain olefin acid; Phenol were oxidized to catechol and catechol were oxidized to straight-chain olefin acid by dioxygenase, Straight-chain olefin acid was finally oxidized to carbon dioxide.This study not only deduced the biodegradation degradation pathway of CY, but also the strains selected was bacteria. The study data on applying the biodegradation of CY to treat environmental pollution and to eliminate or reduce pesticides residue in agricultural produces, thus possessing important theoretical significance and practical value.