Preparation And Application Of Two Pesticide Degradation Bacteria

With the large-scale use of chemical pesticides in agricultural production,the problem of pesticide residues in the environment and agricultural products has attracted increasing attention.Pesticide residues beyond the residual standard not only destroys the surrounding environment,pollutes the biological living space,but also poses a threat to human health,With the improvement of our live standards,a good natural environment and a health body become the goal,therefore,how to repair the polluted area without pesticides has become scientific issue In this study,we used a strain of Bacillus pumilus HZ-2 and Bacillus subtilis BSF01 that has been identified in the early stage to make their preparation,After we applied the preparation to Mesotrione and Beta-cypermethrin polluted LB culture and soil,The results as following:1.By screening a variety of carriers and agents,it was determined that the method for the Bacillus pumilus HZ-2 preparation was made by adding 15%of the carrier Kaolin and 9%of the wetting and dispersing agent to the homogenate of the fermentation broth,Before that,Carboxymethyl cellulose and gum arabic was mixed to the ratio of 3:7.HZ-2preapration was made by centrifugal spray drying technology.After dectection the effective biological content reached to 2.47×10¹⁰ cfu/g,and wetting time at 158 seconds,The suspension rate was 68%,and the pass rate excessed 99%at 100 mesh.2.The normalized degradation rates of 10,25,and 50 mg/L mesotrione in the LB liquid medium by the HZ-2 preparetion were 71%,76%,and 80%,respectively;and corrected degradation of mesotrione in sterilized soil reached 58%,61%and 63%after 14 days.while bacterial preparation was diluted 100,200,500 times and applied to open field,The degradation rate of mesotrione in the soil at a concentration of 260 g/667 m² was 48%,which effectively reduced mesotrione residues in soil.3.Through the screening of carriers and other related additives of BSF01,the bacterial preparations were prepared from the crude Bacillus subtilis BSF01 parent powder.It was determined that BSF01 agent made of 30%crude powder,SDBS was used as a wetting agent,the proportion was 5%,the arabic gum powder was used as a dispersant,the proportion was 7%,potassium phosphate was used as a stabilizer,and the ratio was 4%.The protective agent was a dextrin with a ratio of 1%and the carrier make up to 100%.This preparation was then made to quality test.The spore content of the HZ-2 preparation reached to 6.50×10¹11 cfu/g,the fineness pass rate was more than 99%,the water content was less than 0.6%,the suspension rate was 78%,and the wetting time was 32.0 seconds.Whichwas accordance with national standards for wettable powders.4.The BSF01 strain was applied to a field-degraded test for beta-cypermethrin degradation.The applied concentration of beta-cypermethrin were at 36 and 72mg/kg.When bacterial agents were diluted 100,1000,and 2000 times,they were applied to beta-cypermethrin-contaminated soil.After 5 days of application,100-fold dilutions of preparation were applied to the soil.The degradation rate of beta-cypermethrin reached87.50%,indicating that the obtained microbial agents had a significant degradation effect on beta-cypermethrin.