目录
摘要Ⅱ
关键词Ⅱ
AbstractⅢ
引言
引言1
1 材料与方法1
1.1 试验材料 1
1.1.1 样品1
1.1.2 培养基和试剂2
1.1.3 菌株和质粒2
1.2 试验方法 2
1.2.1 苄嘧磺隆降解菌分离筛选2
1.2.2 16SrDNA序列扩增以及系统发育分析2
1.2.3 菌株BM9降解特性的研究3
1.2.4 菌株BM9降解基因的克隆与分析4
2 结果与分析4
2.1 苄嘧磺隆降解菌株的分离鉴定 4
2.2 菌株BM9的系统发育树分析 4
2.3 菌株BM9对苄嘧磺隆的降解途径 6
2.4 菌株BM9生长与降解苄嘧磺隆的关系 7
2.5 温度和pH对BM9降解苄嘧磺隆的影响 7
2.6 菌株BM9和菌株S113对各种磺酰脲除草剂的降解效果比较8
2.7 菌株BM9降解基因的克隆和分析 9
3 讨论 10
致谢11
参考文献12
除草剂苄嘧磺隆降解菌的分离鉴定及降解特性研究
摘 要
为研发磺酰脲除草剂残留污染的生物修复技术和探究磺酰脲除草剂在环境中的转化过程机制。通过富集驯化技术筛选纯化1株能够以苄嘧磺隆为唯一碳源的高效降解菌株BM9，在30 h内能够降解0.5 mM的苄嘧磺隆，降解效率达到98.6 %。降解苄嘧磺隆的最适温度为30℃，最适pH为7.4。降解菌株BM9还能够降解噻吩磺隆、甲磺隆、苯磺隆和氯嘧磺隆。通过16SrRNA基因序列构建系统发育树，初步鉴定菌株BM9为假单胞菌属（Pseudomonas sp.）。通过高效液相色谱分析发现菌株BM9降解磺酰脲除草剂生成相应的酸，酸不断积累但不能进一步降解，且该菌可以以苄嘧磺隆和甲醇作为唯一碳源生长，因此推测菌株BM9通过酯键水解的方式对磺酰脲除草剂进行降解，该降解途径与先前报道的磺酰脲降解菌株S113的降解途径一致。通过PCR技术，从菌株BM9中扩增出已经报道的水解酶基因su *51今日免费论文网|www.51jrft.com +Q: ^351916072* 
lE。但进一步比较菌株BM9和菌株S113对磺酰脲除草剂的降解，发现菌株BM9的降解能力要高于菌株S113，因此推测菌株BM9中还存在其他的降解基因。菌株BM9对磺酰脲除草剂具有较高的降解效率，后期进一步研究在解决磺酰脲除草剂残留污染问题方面具有实用价值。
ISOLATION AND IDENTIFICATION OF BENSULFURONMETHYLDEGRADING STRAIN AND ITS DEGRADATION CHARACTERISTICS
ABSTRACT
In order to develop the bioremediation technology for residual pollution of sulfonylurea herbicides and explore the transformation process mechanism of sulfonylurea herbicides in the environment. A strain that could uses bensulfuronmethyl as sole carbon source for growth was screened by using enrichment and domestication technology. The strain was named as BM9 and preliminarily identified as Pseudomonas sp. Strain BM9 could degrade 98.6 % of 0.5mM bensulfuronmethyl within 30 h. When the temperature was 30℃ and pH was 7.4, the strain could degrade bensulfuronmethyl with the highest efficiency. Strain BM9 can also degrade thifensulfuronmethyl, metsulfuronmethyl, bensulfuronmethyl and chlorsulfuronmethyl. It was observed by HPLC that BM9 degraded sulfonylurea herbicide to produce corresponding acid, which accumulated continuously but could not be further degraded. Therefore, it is speculated that strain, BM9, can degrade sulfonylurea herbicide by ester bond hydrolysis, which is consistent with the previously reported degradation pathway of sulfonylurea degradation strain S113. The reported hydrolase gene, sulE, was amplified from strain bm9 by PCR. However, further comparing the degradation of sulfonylurea herbicides by strain BM9 and strain S113, it is found that the degradation ability of strain BM9 is higher than that of strain S113, so it was speculated that there were other degradation genes in strain BM9. Strain BM9 has a high degradation efficiency for sulfonylurea herbicides, and further study in the later stage has practical value in solving the problem of sulfonylurea herbicide residue pollution.

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