黑臭河涌沉积物中硝酸盐还原硫氧化微生物氮硫共去除特性

发布时间：2018-05-24 15:24

本文选题：河涌沉积物 + 硝酸盐还原硫氧化细菌(NR-SOB)　；参考：《江西农业大学》2015年硕士论文

【摘要】：最近的研究发现,沉积物中分布着具有硝酸盐还原硫氧化功能的微生物(NR-SOB)。这些微生物可以通过硝酸盐异化还原成铵、硝酸盐还原成亚硝酸盐和反硝化等过程实现硫氧化。其中,尤其是具有硫氧化反硝化功能的NR-SOB可以在将硝酸盐转化为氮气的同时,使具有毒害性的硫化物氧化为单质硫或者硫酸盐,实现氮硫共脱除。甚至,所氧化生成的硫酸盐能一步作为硫酸盐还原菌的电子受体使沉积物中的有机物氧化为二氧化碳,从而实现碳氮硫的共脱除,在沉积物修复中发挥重要作用。珠江三角洲黑臭河涌沉积物中存在着大量含氮、含硫的污染物,但目前有关这类沉积物中NR-SOB的种类及其功能活性特点了解极少。本研究利用前期从珠江三角洲典型黑臭河涌沉积物中获得了具有硝酸盐还原硫氧化功能的菌群F1,分析了该菌群的硝酸盐还原硫氧化功能活性特征,并探索了影响该菌群硝酸盐还原硫氧化功能活性的关键因素。进一步对该菌群进行传代富集,得到了三个不同的NR-SOB菌群(分别命名为F2、F3和F4),分析比较四个菌群的硝酸盐还原硫氧化功能及菌群结构组成,阐明菌群中微生物与菌群功能活性的关系。并进一步分离鉴定了这四个菌群中的关键功能菌株。获得如下主要研究结果:⑴研究从黑臭河涌沉积物环境获得的菌群F1主要经过反硝化作用将硝酸盐还原为氮气,而硫代硫酸盐主要被氧化为硫酸盐,产生的亚硝酸盐和单质硫较少,是能实现氮硫的共去除NR-SOB菌群。pH、Fe~(2+)和Mg~(2+)都对菌群F1的硝酸盐还原硫氧化功能活性有显著的影响。pH为7.5时,菌群F1硝酸盐还原硫氧化功能活性最高,产生更少的亚硝酸盐,同时菌群F1能有较好的pH耐受性,能在pH为5.5时进行硫氧化反硝化作用。Mg~(2+)的存在提高了菌群F1亚硝酸盐还原活性;而Fe~(2+)的存在则抑制了菌群F1亚硝酸盐还原活性。在无氨氮存在时仍然进行硫氧化反硝化作用,与其他沉积物中进行DNRA作用的微生物功能差异很大。⑵高通量测序结果表明,Thiobacillus是菌群F1的优势菌属,占38.63±2.25%的丰度,Alicyclobacillus丰度为约8%。以OTU34034代表的γ-变形菌门丰度约为10.8%。因此,黑臭河涌沉积物中大部分的NR-SOB为未培养的微生物。硝酸盐还原硫氧化功能指标与菌群结构组成相关性分析表明,以OTU34034为代表的Gammaproteobacteria中的微生物、OTU44535和OTU14246为代表的Betaproteobacteria中的微生物及Alicyclobacillus与菌群F1硝酸盐还原硫氧化活性强,产生亚硝酸盐氮及单质硫少有极显著的相关性。而Thiobacillus其丰度的升高会导致菌群F1硝酸盐还原硫氧化活性减弱。而科水平的Rhizobiaceae丰度的升高也会导致菌群F1硝酸盐还原硫氧化功能活性减弱。⑶分离鉴定了129株具有硫氧化反硝化功能的NR-SOB功能菌株。通过16S rRNA基因序列分析结果表明这些菌株分属于5种类型的微生物,分别是固氮菌、卡斯特兰尼氏菌、脱硫弧菌、根瘤菌和硫杆菌。菌群F1中仅分离到了根瘤菌,其他NR-SOB分别在富集菌群中分离得到。因此,人工富集培养过程提高了黑臭河涌沉积物中NR-SOB的可培养性。硫杆菌、固氮菌和根瘤菌属的硝酸盐还原硫氧化产物中亚硝酸盐均较低,其中以硫杆菌的活性最强。而卡斯特兰尼氏菌和脱硫弧菌则产生较多的亚硝酸盐。固氮菌和根瘤菌的硝酸盐还原硫氧化功能在国内外均鲜见报道,极有可能是一些新型的微生物。相关研究结果将为进一步发挥NR-SOB的功能活性,加速黑臭河涌沉积物修复提供科学理论指导。
[Abstract]:Recent studies have found that microorganisms (NR-SOB) with nitrate reduction oxidation function are distributed in the sediments. These microorganisms can be oxidized by nitrate dissimilation reduction, nitrate reduction to nitrite and denitrification. In particular, NR-SOB with sulfur oxidation denitrification function can be used in the removal of nitrate. When it is converted into nitrogen, the toxic sulphides are oxidized into elemental sulfur or sulphate to achieve nitrogen and sulfur removal. Even the oxidized sulfate can be used as the electron acceptor of the sulfate reducing bacteria to oxidize the organic matter in the sediments to carbon dioxide, and the CO removal of carbon, nitrogen and sulfur is achieved, and in the restoration of sediment There are a large number of nitrogen and sulfur containing pollutants in the sediments of the black and smelly river in the Pearl River Delta, but there is little understanding of the species and functional activity of NR-SOB in this kind of sediments. The bacterial group F1, analyzed the characteristics of the functional activity of the nitrate reduction oxidation of the bacteria group, and explored the key factors affecting the functional activity of the nitrate reduction oxidation of the bacteria group. Further, three different NR-SOB bacteria groups (named F2, F3 and F4) were obtained, and the nitrate of the bacteria group was analyzed and compared. The relationship between the oxidation function of the original sulfur and the structure of the bacteria group, clarifying the relationship between the microbial community and the functional activity of the bacteria group. And further separating and identifying the key functional strains of the four bacteria groups. The main results are as follows: (1) the study of the bacterial group F1 obtained from the sediment environment of the black odor river is mainly reduced to the nitrate by denitrification. Nitrogen, while thiosulfate is mainly oxidized to sulphate, producing nitrite and sulfur less, is a common removal of NR-SOB bacteria.PH, Fe~ (2+) and Mg~ (2+) have significant effect on the functional activity of nitrate reduction and oxidation of the bacterial group F1, when.PH is 7.5, the functional activity of the microbial group F1 nitrate reduction sulfur oxidation is the highest. Less nitrite, at the same time, the bacteria group F1 can have better pH tolerance, and the presence of sulfur oxidation denitrification.Mg~ (2+) can increase the reduction of nitrite reduction activity of bacteria group F1 at the time of pH 5.5, while Fe~ (2+) inhibits the F1 nitrite reduction activity of the bacteria group. The microbial function of the DNRA action in the sediments is very different. (2) high throughput sequencing results show that Thiobacillus is the dominant genus of bacteria group F1, accounting for 38.63 + 2.25% abundance. The abundance of Alicyclobacillus is about 8%., the abundance of gamma deformable bacteria is about 10.8%., and most of the NR-SOB in the black and smelly river sediments is not cultured. The correlation analysis between the functional indexes of nitrate reduction sulfur oxidation and the structural composition of bacteria group showed that microbes in Gammaproteobacteria, OTU44535 and OTU14246 represented by OTU34034, and Alicyclobacillus and Alicyclobacillus and microbial group F1 nitrate reduced sulfur oxidation activity and produced nitrite. There was a very significant correlation between nitrogen and sulfur, but the increase in the abundance of Thiobacillus could lead to the reduction of the oxidation activity of the microbial group F1 nitrate reduction, and the increase of the Rhizobiaceae abundance of the family level also resulted in the decrease of the functional activity of the reduction sulfur oxidation of the bacteria group F1 nitrate. (3) 129 strains of NR-SOB with the oxidation denitrification function of the NR-SOB were identified. Functional strains. The results of 16S rRNA gene sequence analysis showed that these strains were divided into 5 types of microorganisms, namely nitrogen fixing bacteria, Custer ranibe, Vibrio desulphuri, Rhizobium and Thiobacillus. The bacteria group F1 isolated only the rhizobia, and the other NR-SOB were separated in the enriched bacteria group respectively. Therefore, the artificial enrichment culture process was improved. The culturability of NR-SOB in the sediments of the black and smelly rivers. The nitrites in the nitrate reduction oxidation products of Thiobacillus, nitrogen fixing bacteria and Rhizobium are low, and the activity of Thiobacillus is the strongest, while the Custer and the Vibrio desulphuri produce more nitrite. The nitrate reduction and oxidation function of nitrogen fixing bacteria and Rhizobium bacteria There are few reports at home and abroad. It is likely to be some new microbes. The results of the study will provide scientific theoretical guidance for further exerting the functional activity of NR-SOB and accelerating the restoration of black and smelly river sediments.
【学位授予单位】：江西农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X172;X52

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