河流脱氮微生物的筛选及脱氮特性研究

发布时间：2018-01-09 15:23

  本文关键词：河流脱氮微生物的筛选及脱氮特性研究　出处：《郑州大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 氨氮 菌种鉴定 脱氮效率 菌种驯化

【摘要】：河流、湖泊等水体中氨氮浓度超标是引发我国水体污染的主要因素之一,氨氮超标引起的诸多问题成为近年来研究的热点。本文从郑州市贾鲁河主干流及上游支流采集水样,分析水体污染特点。通过富集、分离、纯化等手段从样品中筛选出来7株脱氮菌,检验菌株的脱氮特性,选择其中3株考察其对河水中氨氮的去除效果。对贾鲁河水体污染特点分析,结果显示:贾鲁河水体氨氮浓度超标是最主要的污染问题;研究区域内COD浓度沿程变化不规律,DO值上游高于下游,各形态氮含量沿程基本呈现上升趋势。根据COD、各形态氮以及DO值变化等分别选择各批次部分点位的样品作为微生物筛选重点研究对象。利用铵盐有机和无机培养基富集3个批次的水样,经过1月左右富集完成,春、夏季批次样品富集情况良好,PCR-DGGE分析结果显示:富集液中Thermomonas brevis strain(反硝化细菌热单胞菌)、Pseudomonadaceae bacterium(假单胞杆菌科细菌)等明显占优势,且存在可能具有异养硝化作用的Pseudomonas sp.(假单胞杆菌)、Flavobacterium Bergey(黄杆菌)、Rhizobium(根瘤菌),未发现自养型脱氮菌。从3个批次的富集液中分离出纯菌共110株,比较其对氨氮的去除效率,初步筛选出脱氮效率较高的22株菌,结合16S r DNA测序分结果,并查阅文献,选取其中可能具有异养硝化作用的C2、C30、C31、C42、C49、NC13、NC63共7菌种鉴定,结果表明:C2、C30、C31、C42、C49为假单胞杆菌,分别与Pseudomonas putida(恶臭假单胞杆菌)、Pseudomonas mendocina(门多萨假单胞杆菌)、Pseudomonas mendocina、Pseudomonas chengduensis、Pseudomonas oleovorans(石油假单胞杆菌)表现出较小差异性;其余2株菌NC13和NC63可基本确定为Diaphorobacter nitroreducens和Pseudoxanthomonas mexicana。所筛选出的7株菌对氨氮均具有较高的去除率,24h内对培养基内氨氮的去除率最高达91.8%,但去除方式多为细菌的同化作用,约20%~25%的氨氮在5株假单胞杆菌体内通过异养硝化作用被还原成气体逸出。7株菌最适生长温度在30℃左右;菌株C2、C30为中性菌,中性条件便可生长很好,菌株C31和C42更易于在偏碱性的条件下生长。菌株C42能利用不同的碳源,以柠檬酸钠为碳源时脱氮效果最佳,其余菌株更易利用丁二酸钠。通过培养条件优化发现,转速的提升最有利于菌株提高脱氮效率。选取C2、NC13、NC63研究其对河水中氨氮的去除效果,发现将菌株直接投加于河水时,菌株易因营养条件不足而死亡,对河水中氨氮无去除效果;因此采取逐渐降低外加碳源和氮源浓度的方式逐步进行菌种驯化,经过两个周期驯化,假单胞杆菌C2驯化初见效果,对环境中氨氮去除后残余量达4.53mg/L,其余2株菌能适应驯化过程,但去除氨氮效果不明显。
[Abstract]:The concentration of ammonia nitrogen in rivers, lakes and other water bodies is one of the main factors causing water pollution in China. In recent years, many problems caused by excessive ammonia nitrogen have become a hot topic. In this paper, water samples are collected from the main stream and upstream tributaries of the Jaru River in Zhengzhou City, and the characteristics of water pollution are analyzed, and the characteristics of water pollution are analyzed through enrichment and separation. Seven strains of denitrifying bacteria were screened out from the samples by purification methods. The denitrification characteristics of the strains were tested, and three of them were selected to study the removal effect of ammonia nitrogen in the river water, and the characteristics of water pollution in the Jaru River were analyzed. The results show that the concentration of ammonia and nitrogen in the water of the Jaru River is the most important pollution problem. The variation of COD concentration in the study area was irregular. The do value in upstream was higher than that in downstream, and the nitrogen content in all forms showed an upward trend along the course. According to COD. Each nitrogen form and do value were selected as the main research object of microbial screening. The three batches of water samples were enriched with ammonium salt organic and inorganic medium. The samples were enriched well in spring and summer after enrichment on January. PCR-DGGE analysis showed that Thermomonas brevis strain (denitrifying bacteria) was found in the enriched solution. Pseudomonadaceae bacteria (Pseudomonas bacteria) and other obvious advantages. And there is Pseudomonas sp. (Pseudomonas pseudomonas) that may have heterotrophic nitrification (Flavobacterium Bergeyium). Rhizobium (Rhizobium, no autotrophic denitrifying bacteria) was isolated from three batches of enrichment solution, and 110 strains of pure bacteria were isolated, and the removal efficiency of ammonia nitrogen was compared. 22 strains with high denitrification efficiency were preliminarily screened. The results of 16s r DNA sequencing were used to select C2C30C31C42, which may have heterotrophic nitrification. Seven strains of C49-NC13NC63 were identified. The results showed that C31C42C49 was Pseudomonas spp. And Pseudomonas putida (Pseudomonas mendocina). Pseudomonas mendocina,Pseudomonas chengduensis. Pseudomonas oleovorans (Pseudomonas petroleum) showed a small difference; The other two strains, NC13 and NC63, can be basically identified as Diaphorobacter nitroreducens and Pseudoxanthomonas. The 7 strains screened by mexicana. all had high removal rate of ammonia nitrogen. The highest removal rate of ammonia nitrogen in culture medium was 91.8% within 24 hours, but most of the removal methods were bacteria assimilation. About 20% of ammonia nitrogen was reduced to gas escape by heterotrophic nitrification in 5 strains of Pseudomonas spp. The optimum growth temperature was about 30 鈩，

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