Research On Isolatio And Degradation Characters Of Butachlor Advantage Degradation Bacterium

Butachlor is an effective amide herbicide which is mainly used for controlling pre-emergence weeds and used widely in China. However, wide spread of butachlor has inevitably brought pollution to the environment and severe phytotoxicity to crops. Therefore,to find methods for resolving these problems brought by butachlor is extremely urgent.12strains with good butachlor-degrading effect were isolated from butachlor contaminated soil and water by enrichment culture, and a degrading bacteria with favorable degradaing effect of butachlor was named D107.Then D107was identified and the growth and degradation character of the bacteria under different environmental condition was studied.Meanwhile,bioremediation effect of D107to butachlor phytotoxicity on rice was investigated.The main results were as follows:1.12strains with good butachlor-degrading effect were isolated and a degrading bacteria with favorable degradaing effect of butachlor was named D107. Based on its morphological characteristics,biochemical characteristics and16SrDNA gene analysis, strain D107was identified as Aeromonas punctata.2. Based on experiments under different environmental conditions, the optimum culture condition of D107was determined as initial butachlor concentration of20mg·L-1, no carbon source,bacterial inoculation of5%(volume ratio),pH of7and temperature of37℃.3. Under optimum culture condition for3d,the degradation rate constant of D107was0.0152and relevant half-life of butachlor was1.89d,which was in accordance with the first-order kinetic equation.These results would provide reference price for practical application of this degrading bacteria.4. The test result of interior show that under indoor temperature of28℃,photoperiod of16h illumination and8h dark for7d,application of5%(volume ratio) D107had the most significant remediation effect on20mg·L-1butachlor phytotoxicity.Inhibition ratio on plant height and germination ratio of rice decreased respectively25.34%and39.07%compared with treatment with no D107application. All results obtained could provide theoretical basis for butachlor bioremediation in practical field application.