| As greatly insecticidal efficiency and spectrum on crops pests, especially soil pest, carbofuran was deeply preference and has extremely extensive using in the agricultural production. In recent years, how to deal with the carbofuran residues was becoming a prominent problem for the increasingly harm of environment and animals. To cope with the harm of carbofuran residues, bacteria degradation method was utilized by the people, and some carbofuran-degrading bacteria were separated from environment including Sphingomonas, Pseudomonas, Paracoccus, and Serratia, etc.A carbofuran-degrading bacterium CF-14 with higher degradation rate was isolated this study, and the degradation condition was optimized with the method of response surface analysis. These results were laying the foundation for the future study of pollution repair. Research contents and main results as follows:1. Using the domestication and enrichment methods, this work scaned a carbofuran -degrading bacterium CF-14 from farmland soil. By the morphological observation, physiological/biochemical characteristics identification and 16S rDNA sequence of molecular biology analysis, the bacterium CF-14 was identified as Achromobacter CF-14.2. Making carbofuran as the only carbon source in liquid inorganic salt medium, we cultured the strain CF-14 for 3 d. Using liquid chromatography technique, we preliminary obtained that the degradation rate of carbofuran by strain CF-14 reached 95%.3. To optimize the degrading condition of carbofuran degrading strain CF-14, we used the Plackett-Burman Design design to screen 4 influenced factors for carbofuran-degrading strain CF-14 from 8 facfors: pH, inoculation quantity, culture time, temperature. The Box-Behnken Design experiment was used to sure the best degrading condition of Achromobacter CF-14: culture time 73.0 h, pH value 7.0, temperature 28.0℃and quantity 13.0 mL cfu(bacteria concentration was 10~7 cfu/mL). Under this condition, the forecast degradation rate was 100%. After experiments, the actual degradation rate reached 99.5%. |
