Isolation And Characterization Of Ethametsulfuron Degrading Fungi F12

Ethametsulfuron , belongs to the group of sulfonylurea herbicides,was consumedly restricted for its long residue and thereout resulted in badly crop injury of post sensitive crop. Therefore it had weightily significance to develop a method for the detoxification of ethametsulfuron residues in agriculture soil and elimination of its harmful effect on substitution crop.In the study, one ethametsulfuron-degrading strain was isolated by biological concentration and domestication,then purificated in solid culture medium,and mensurated the rate of ethametsulfuron-degrading by HPLC Its growth characteristic, degrading ability were also investigated. The brief results are follows.68 strains were isolated by enrichment culture and domestication from soil samples in limber hole of Hunan haili chemical industry company.The fungal strain F12 was select for the best capable of utilizing ethametsulfuron by HPLC detecting. Based on the results of biomorphic features, type culture medium, and phylogenetic similarity of rDNA-ITS gene sequences, the isolated strain was designated as Penicillium expansum Link The rDNA-ITS partial sequences were deposited into the GenBank under accession No. EU128638.1.Through the biological character culturing on different condition, F12 favors PDA culture medium. The mycelium of F12 grew best under the temperature of 25℃and the pH of 6.0. The conidium germinated best with the temperature of 20℃, the pH of 5.0 and high moisture. At the same time, the results showed The strain F12 growth liked darkness better.By F12 culture based on utilizing ethametsulfuron as sole carbon source in inorganic salt solution, as a result, F12 adapt to degrade ethametsulfuron in the original concentration of 20mg/L, the inculation of 8%, the pH of 6.5 and the temperature of 28℃circumstances. In the fittest conditon, the ethametsulfuron degrading curve described by first order kinetics reaction equation linear regression, Ethametsulfuron degradation kinetics follow the first order kinetics: C_t=23.94·e^-0.0221t,Its square of Correlation coefficient was 0.9865. 92.33% of ethametsulfuron was removed after 25d In fittest culture condition. The soluble enzymes from cell-free extracts of strain F12 can degrade 87.32% of ethametsulfuron in 72h.This shows that the soluble enzymes were the primary removal enzymes. 91.90% and 89.02 of the initially added 20 mg/L ethametsulfuron was removed after 25d for natural dried fresh soil and sterilized soil inoculated with strain F12. In contrast, Only 14.81% and 8.05% was removed in uninoculated natural dried fresh soil. Therefore, ethametsulfuron removal improved significantly in soils inoculated with strain F12.