|关键词||二苯砷酸 紫金牛叶杆菌 共代谢降解 化学诱变 土壤 微生物修复 微生物功能多样性|
|其他摘要||Diphenylarsinic acid (DPAA) is a new type of environmental pollutant produced by the hydrolysis and oxidation of arsenic containing chemical weapons after leaking. Because of its stable chemical properties, not easily degraded and strong biological toxicity, DPAA can be enriched through the food chain, thus a serious threat to the soil and groundwater environment safety and human health. Therefore, it is urgent to carry out the research on remediation mechanism and technology of DPAA contaminated soil in chemical weapons residual area. Microbial remediation has been widely used in the remediation of organically contaminated soil. However, the current international research on microbial remediation of DPAA contaminated is still limited. In this study, a strain capable of aerobic degradation of DPAA was screened from the three strains stored in the laboratory, which was subjected to co-metabolism degradation by external carbon source and by the chemical mutagens N-methyl-N’-nitro-N-nitrosoguanidine (NTG). It was shown that the degradation efficiency of DPAA was further improved through the two degradation approaches. Accordingly, the degradation characteristics and metabolic intermediates of DPAA were elucidated and the remediation potential of DPAA-contaminated soil was assessed by soil micro-domain experiment with red soil and black soil. This study provides the new microbial resource and scientific basis for further research and development in bioremediation of DPAA polluted soil.|
The main conclusions of this study are as follows:
（1）The results showed that the three strains could not survive with DPAA as the sole carbon source and energy. When the sucrose was used as a co-metabolic substrate, only the strain RC6b significantly increased the DPAA degradation rate (about 14%), and the strain RC6b was identified as DPAA-degrading bacteria.
（2）The strain RC6b was able to effectively degrade DPAA in the solution under the condition of the co-metabolizing matrix. The degradation rates of DPAA in the solution were 14.08%, 15.21% and 15.05% 28 days after addition of sucrose, glucose and sodium acetate, respectively. There was no significant difference among the different carbon sources.
（3）The degradation efficiency of the obtained strain was significantly higher than that of the original strain when the strain was chemically mutated with N-methyl-N’-nitro-N-nitrosoguanidine as the mutagenic agent. The degradation rates of DPAA by using the mutant strain N-RC6b2 was up to 36.71% 28 days after culture with DPAA as the sole carbon source. It is suggested that DPAA undergo a monohydroxylation reaction during the degradation process, producing a metabolic intermediate monohydroxylated DPAA.
（4）Soil microbial remediation experiments showed that DPAA in the contaminated soils could be effectively degraded by the strain N-RC6b2. Microbial remediation of DPAA contaminated soil was carried out 90 days after addition of inoculated strain N-RC6b2. The removel rates of DPAA in red soil and in black soil increased up to 57.72% and 52.90%, respectively. The soil AWCD value and soil microbial community diversity indexs significantly increased compared with the control group, indicating that the soil microbial environment quality after bioremediation was improved effectively.
|宋芳. 二苯砷酸高效降解菌的筛选强化及其对污染土壤的修复作用[D]. 北京. 中国科学院大学,2017.|