| This test designed research program according to research guide of <> .To study on ecological effect of Atrazine-degrading strains the type of Atrazine-degrading the kinetics of degradation reaction and the environmental factors affecting degradation reaction by indoor and field experiments, bioremediation technology of Atrazine contaminated soil was provided.1. The actinomyces designated as S1 S2 and S3 were isolated and selected from Atrazine contaminated soil, and they were regarded as Atrazine-degrading strains in the test. They were returned to soil by acclimatization and enrichment so that Atrazine contaminated soil was bioremedied and restored microecological environment.2. The results of the indoor research showed that the strains grew fine under 20~30 ℃,and grew slowly below 10℃ or above 35℃.The suitable pH range of strains was pH 6.0~8.0.The strains that didn't regard Atrazine as the sole nutriment depended on original substrate in the growth period and the enzyme that maintained the metabolism came from the utilization of the source of carbon and nitrogen. The metabolism of Atrazine was combined with consuming original substrate.3. The results of ecological effect indicated: When the inoculated strains coexisted possibly with indigenous microorganism, cell amount of inoculated strains in soil was 100~1000 times higher than that of indigenous microorganism. Under the optimum soil condition, maintained microbial activity was advantageous to Atrazine degradation. Under the indoor test, after inoculating in soil growth curve occurred two peaks so thatcell amount reached 10 and maintained dynamic balance. Under the field test, cell proliferated rapidly in sterilized soil, but cell divided slowly at the beginning of inoculation and the growth curve didn't occurred apparent lag phase. The rate of cell division accelerated and the capable of cell proliferation strengthened to 10 days or so. The cell amount generally maintained the level about stationary phase after planting ginseng, respectively, during the period of 20~78 days of sterilized soil, 47~75 days of fertilized soil and 20-56 days of fallow. In autumn, cell amount in soil increased and occurred the second growth-peak. By the different treatment for sterilized soil and fertilized soiL planting ginseng and fallow, the growth curve change of inoculated strains was in accord, but cell amount had apparent difference. This indicated that inoculated strains may suit for optimal soil environment and metabolized Atrazine withindigenous microorganism.4. Kinetics research indicated: under the action of microorganism, biodegradation process of Atrazine in soil accorded with first order reaction kinetics model fitting curve's index of correlation was above 0.81. Inoculated soil by single or mixed Atrazine-degrading strains, degradation speed of Atrazine was quickened obviously and the katabolites had been detected. In asepticized soil, degradation speed of Atrazine slowed down, but didn't produce katabolites. Results showed that disappearance type of Atrazine in soil could be different, soil microorganism played certain role during Atrazine's disappearance. It was influenced by environmental factors such as type of inoculated strain inoculation amount soil temperature soil pH soil treatment way nutrition substrate. Degradation speed of Atrazine in soil also had significance difference.5. Degradation reaction type of Atrazine research results indicated: because microorganism participated, degradation reaction process of Atrazine was intensified under this conditions, apparent activation energy was reduced and fully reflected the feature of biodegradation. Abiotic degradation half-life of Atrazine in soil was 117.5-105.9days; half-life of indigenous microorganism metabolic Atrazine was 28.4~26.6days; under the optimum bioremediation condition, its degradation half-life was 2.7-3.3days. After remediation, disappearing 95% Atrazine i... |
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