脱氮细菌的选育及其在养殖水体氮素转化中的作用

发布时间：2018-01-30 01:58

本文关键词： 好氧反硝化紫外诱变脱氮特性养殖水体 N元素　出处：《南京理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：好氧反硝化细菌被发现以来一直是国内外研究的热点,它克服了传统反硝化工艺的不足,可以在好氧条件下进行反硝化作用,有着很强的应用潜力。本文利用实验室中选育的好氧反硝化菌种,通过物理法紫外诱变提高其反硝化能力。将诱变后的菌株应用于模拟养殖水体的脱氮处理研究,并对模拟水体中不同形态的氮素随时间的变化的数据做了曲线拟合,探讨了不同生境条件下的水中N元素的变化。在物理法紫外诱变阶段,-对实验室前期选育的好氧反硝化菌6#菌进行紫外诱变处理,经过初筛和复筛得到菌株H2,并对其好氧反硝化性能进行研究。结果显示：菌株H2的反硝化能力得到改善,在相同实验条件下,H2对硝酸根的去除能力从原始菌株的59.86%提高至68.66%,且在突变体的筛选、活化和培养过程中经过多次传代,传代前后H2遗传稳定性良好。由杜氏小管实验得出H2菌产生气体量2.5 mL大于6#菌的2 mL,也可推出H2菌比原菌株6#具有更好的硝化反硝化作用。在模拟养殖水体的实验阶段,选用空白水体、水生植物+菌、菌以及水生植物四种模拟环境进行实验,探究诱变菌H2对水体的净化效果以及水生植物对水体净化作用的影响,净化效果为水生植物+菌菌水生植物空白水体。实验证明,H2对氨氮、硝态氮、亚硝态氮、COD均具有一定的去除作用,尤其是对亚硝态氮去除效果显著；H2菌对于水体净化效果良好,水生植物对水体的净化也有一定的影响作用；菌、水生植物均可改善水质,提高鱼体的生长性能。对模拟养殖水体中氮素浓度与时间的变化关系进行数学分析,在本实验条件下,数学参数与实际运行相符,所得数学方程能够很好地反映水体氮素转化降解规律。从方程可以明显看出反硝化菌H2、水生植物对氮素的去除规律。研究表明,运用紫外诱变的方法有效地提高了反硝化菌的脱氮能力,提高了水体净化效果,并且在养殖水体脱氮处理中效果显著。
[Abstract]:Aerobic denitrifying bacteria have been a hot research topic at home and abroad since they were discovered. It overcomes the shortcomings of traditional denitrification process and can be denitrified under aerobic conditions. This paper uses aerobic denitrification strains selected in laboratory. The denitrification ability was improved by physical ultraviolet mutagenesis. The mutated strain was applied to the denitrification treatment of simulated culture water. The variation of N element in water under different habitat conditions was studied by curve fitting of the data of different forms of nitrogen changes with time in the water, and in the phase of physical ultraviolet mutagenesis. The aerobic denitrifying bacteria 6# was treated by ultraviolet mutagenesis, and the strain H2 was obtained by screening and rescreening. The aerobic denitrification performance of strain H2 was studied. The results showed that the denitrification ability of strain H2 was improved under the same experimental conditions. The removal of nitrate by H2 increased from 59.86% to 68.66, and was subcultured many times during the selection, activation and culture of the mutants. The H _ 2 genetic stability was good before and after passage, and the gas production of H _ 2 was 2.5 mL larger than 2 mL of 6 # by the Duchenne tubule test. It can also be concluded that H2 bacteria have better nitrification and denitrification than original strain 6#. In the experiment stage of simulated culture water, the blank water body and aquatic plant bacteria were selected. Four simulated environments of bacteria and aquatic plants were carried out to explore the purification effect of mutagenic bacteria H2 on water body and the effect of aquatic plants on water purification. The purification effect was blank water body of aquatic plant bacteria. The experiment proved that H _ 2 has certain removal effect on ammonia nitrogen, nitrate nitrogen and nitrite nitrogen COD, especially on nitrite nitrogen removal. The purification effect of H _ 2 bacteria is good, and the purification of water body is also influenced by aquatic plants. Bacteria and aquatic plants can improve the water quality and improve the growth performance of fish. The mathematical analysis of the relationship between nitrogen concentration and time in the simulated aquaculture water body shows that the mathematical parameters are consistent with the actual operation under the experimental conditions. The mathematical equations obtained can well reflect the nitrogen conversion and degradation law of water body, and the nitrogen removal law of denitrifying bacteria H _ 2 and aquatic plants can be clearly seen from the equation. Ultraviolet mutagenesis was used to improve the denitrification ability of denitrifying bacteria and the purification effect of water body, and the effect was remarkable in the denitrification treatment of aquaculture water.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X172;X714

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