Repairing Two Types Of Pesticide Contaminated Soil By Immobilized Microorganism Technology

Chlorpyrifos and carbofuran are two common broad-spectrum insecticides. Human’snerve system can be strongly destructed, even leading to death under a long-term exposure.In addition, chlorpyrifos and carbofuran are hard to be naturally degraded, because of thestrong combination with soil particles and long half-life. So repairing the polluted soil isurgently needed. This paper focuses on degradation of contaminated soil through theimmobilized microorganism technology method, in order to find a new way forchlorpyrifos and carbofuran restoration.In this study, we elected out ten more strains which can degrade chlorpyrifos andcarbofuran through enrichment and domestication. It could be got two dominantdegradation bacteria respectively through preliminary screening and rescreening: LLBD2、LLBD4、 LLBK2and LLBK10. After16SrDNA analyzing, the results showed thatLLBD2、LLBK2、LLBK10were Bacillus cereus, LLBD4was bacillus sp. At the sametime the embedding and crosslinking immobilization method were used to studying for thestrains, the results showed: bacteria immobilized on the degradation of chlorpyrifos andcarbofuran were significantly better than the free bacteria, and half-life was also greatlyreduced. The degradation rate was83.28%after LLBD2within72h by H1carrierimmobilized. The degradation rate was84.52%after LLBK2within72h by H3carrierimmobilized.Further more, the environmental factors influenced with LLBD2and LLBK2showedthat immobilized bacteria were more adapted to the changed environment than the free one.Although the initial concentration、pH、temperature significantly changed of pollutants, thedegradation of immobilized bacteria rate fluctuation more stable. It showed thatenvironmental factors had little influence on the immobilized bacteria. The immobilizedmicroorganism had a strong ability to adapt the poor setting.