新疆长期连作棉田高效氯氰菊酯降解菌群的构建及特性

发布时间：2018-04-13 10:46

  本文选题：生物降解 + 混合菌群　； 参考：《新疆师范大学》2015年硕士论文

【摘要】：新疆地区棉花长期大面积栽培造成当地土壤中农药等的面源污染,同时也孕育了丰富的农业污染物降解微生物资源。本研究以新疆地区连作10 a以上的棉田土壤作为研究材料,以高效氯氰菊酯作为唯一碳源和能源,首先采用逐渐加量和连续传代该菌源的驯化方式,从土壤中初步获得并确定能稳定传代且可以持续降解氯氰菊酯的菌群。其次,利用稀释涂布的方法,从高效氯氰菊酯降解菌群中筛选可培养微生物,根据菌落形态观察,初步确定筛选出11株可培养微生物,分别编号为GX2-GX12。采用CTAB/Na Cl法提取细菌总DNA,PCR扩增得到各菌株的16Sr DNA。测序所得全部序列经16Sr DNA同源性分析该菌群结构组成,结果表明该菌群由10株铜绿假单胞菌(Pseudomonas aeruginosa)和1株无色杆菌属(Achromobacter)构成。11株菌中10株与绿铜假单胞菌(Pseudomonas aeruginosa)相似性为99%,1株与无色杆菌(Achromobacter mucicolens)相似性达到99%。通过对获得的菌株序列比对分析,可以了解棉田土壤中能降解高效氯氰菊酯的可培养微生物种类较少,其中优势微生物是绿铜假单胞菌的菌株,占到90.91%。而无色杆菌的菌株占9.09%。因此推断本实验中所获得的降解高效氯氰菊酯的微生物主要是绿铜假单胞菌。第三,以初始农药浓度(100、150、250 mg/L)、温度(27、32、37℃)、初始p H(6.5、7.0、7.5)、装样量(100、200、300 m L/500 m L)为试验因素,采用四因素三水平的正交试验方法,对该菌群降解高效氯氰菊酯的特性做了初步研究,每组试验做3个重复。试验结果表明,该混合菌群具有较宽的环境适应性,以LB培养基做种子液,极差分析,最优条件:初始农药浓度250 mg/L,温度27℃,初始p H 7.5,装样量300 m L;方差分析:只有p H这一因素不显著,最适条件:初始浓度250 mg/L,温度27℃,装样量300 m L;测得在培养48 h时,降解率为96.15%,144 h,降解率为84.27%,204 h,降解率为86.98%;以无机盐培养基做种子液,极差分析:最优条件:初始农药浓度250 mg/L,温度27℃,初始p H 7.0,装样量200 m L;方差分析:初始农药浓度不显著,主体间效应:温度装样量p H,最适条件:温度27℃,初始p H7.0,装样量200m L。测得在培养24 h时,降解率为68.81%,132 h时,降解率为92.39%。混合菌群降解高效氯氰菊酯的异构体选择性结果表明,混合菌群对高效氯氰菊酯的降解并没有明显的立体异构体选择性。本研究获取了适合新疆地区土壤类型、气候环境条件下高效氯氰菊酯农药面源污染修复的微生物资源,旨在为新疆地区土壤环境修复、恢复及开发该地区环境条件下的生物资源打下基础。
[Abstract]:Cotton cultivation in Xinjiang for a long time resulted in non-point pollution of pesticides in local soil and abundant microbial resources for degradation of agricultural pollutants.In this study, the soil of cotton field in Xinjiang area was used as the research material, and the high efficiency cypermethrin was used as the sole carbon source and energy source. Firstly, the acclimation mode of the bacteria source was gradually added and subcultured continuously.A stable subculture and sustainable degradation of cypermethrin was obtained from soil.Secondly, the culturable microorganisms were screened from the high efficiency cypermethrin degrading bacteria by the method of dilution coating. According to the colony morphology observation, 11 culturable microbes were preliminarily selected and numbered GX2-GX12.The 16Sr DNA of each strain was obtained by CTAB/Na Cl method.The sequence was analyzed by 16Sr DNA homology.Through the sequence alignment analysis of the obtained strains, we can find out that there are few culturable microorganisms in cotton field soil that can degrade high efficiency cypermethrin, among which the dominant microorganism is Pseudomonas aeruginosa, which accounts for 90.91%.But the strain of colorless bacillus accounted for 9.09%.Therefore, we infer that the main microorganism for degradation of cypermethrin in this experiment is Pseudomonas chloridii.Three repetitions were made in each group.The results showed that the mixed bacteria had wide adaptability to the environment. Using LB medium as seed solution, the optimum conditions were as follows: initial pesticide concentration 250 mg / L, temperature 27 鈩，

本文编号：1744163