| 摘要: |
| 以太湖底泥沉积物为菌源，分离筛选到两株氨化菌，分别命名为AB-1和AB-2。通过形态特征观察、生理生化特性分析及16S rDNA分子鉴定，确定菌株AB-1和AB-2分别为三叶假单胞菌（ Pseudomonas migulae）和节杆菌（Arthrobacter sp.）。相同条件下，两种菌都以1%接种量接种至有机氮中培养70 h，结果表明菌株AB-2去除有机氮的效率高于AB-1，去除率为83.15%，而菌株AB-1的去除率仅为67.33%。所分离的AB-2菌株对于湖泊富营养化治理中改善水质环境有一定的应用价值。 |
| 关键词: 有机氮 氨化菌 分离鉴定 降解效果 |
| DOI：10.7515/JEE192010 |
| CSTR：32259.14.JEE192010 |
| 分类号: |
| 基金项目:国家自然科学基金项目（51378175） |
| 英文基金项目:National Natural Science Foundation of China (51378175) |
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| Isolation and degradation effect of two ammonifying bacteria |
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WANG Hong, XU Jie, RUAN Aidong, XU Yaofei, WEI Qi, LI Siyan
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1. State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China
2. College of Hydrology and Water Resources, HoHai University, Nanjing 210098, China
3. Guizhou Provincial Water Conservancy Research Institute, Guiyang 550001, China
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| Abstract: |
| Background, aim, and scope In recent years, with the rapid development of economy, a large number of nutrients such as nitrogen, phosphorus and other organic substances enter the water, causing eutrophication of the water, and water resources problems are serious. Nitrogen removal in eutrophic water has always been a research hotspot. Up to now, there have been a lot of studies on the removal of inorganic nitrogen such as ammonia nitrogen, nitrate nitrogen and nitrite nitrogen in water, among which the research on the ammoniation process of organic nitrogen is relatively less. In order to further understand the nitrogen cycle process of lake, the paper took ammoniated functional bacteria as the research object to explore the ammoniated functional bacteria in lake and sediments, and hopes to screen out high efficiency ammoniated bacteria, which can play a role in the treatment of nitrogen pollution in Taihu Lake. Materials and methods In this experiment, samples were collected from the bottom sediments of Taihu Lake. After repeated screening, two strains of ammoniated bacteria were isolated, and named AB-1 and AB-2 respectively. The strains were identified by the morphological features observation, physiological and biochemical characteristics analysis, 16S rDNA molecular identification and homology analysis. In addition, the growth characteristics and degradation effects of two strains of ammoniated bacteria were compared. (1) The OD value was measured at 600 nm wavelength every 2 hours after incubation in constant temperature and dark oscillation at 28℃ for 120 r·min−1, and the growth characteristics were determined. (2) Inoculate 1% of the inoculated amount into organic nitrogen, incubate continuously for 70 hours under the same conditions, and measure the changes of ρ (NH4+-N) and ρ (TN) to compare the degradation effects of the two strains. Peptone was used as the sole organic nitrogen source in the experiment, so the content of organic nitrogen could be expressed by the difference between TN and NH4+-N in the initial culture medium, and the degradation rate of organic nitrogen could be expressed by the increase of NH4+-N. Results Through morphological analysis and 16S rDNA molecular identification, strains AB-1 and AB-2 were identified as Pseudomonas migulae and Arthrobacter sp., respectively. Under the same culture conditions, the growth potential of strain AB-2 was greater than that of strain AB-1, and the maximum OD600 was 1.063 and 0.851, respectively. Besides, two strains of ammoniating bacteria had strong ammoniation ability. Among them, the removal efficiency of organic nitrogen by strain AB-2 was higher than that of ammoniating bacteria AB-1, the removal rate was 83.15%, and that of strain AB-1 was only 67.33%. Discussion Compared with other studies on the degradation of organic nitrogen by ammoniating bacteria, it was found that the degradation rate of organic nitrogen by the two strains was slightly higher. This may be because the ammoniating ability of the two strains was improved by multiple screening in the process of selecting strains. Furthermore, the initial concentration of organic nitrogen in this study was lower, which indicated that the strains screened were indeed effective in degrading organic nitrogen. In addition, by monitoring the growth of two strains of ammoniating bacteria and the change of NH4+-N content, it was found that strain AB-2 could degrade organic nitrogen for a long time, which indicated that the strain could be used as a candidate strain for high-efficiency degradation of organic nitrogen, and it was feasible to apply it to lake eutrophication treatment to improve water quality and environment. However, the conditions, mechanism, enzymatic activity and application methods of ammonia nitrogen degradation need to be further explored and studied. Conclusions In the study, two strains of ammonifying bacteria AB-1 and AB-2 were isolated from sediment of Taihu Lake. Both of them had strong ammoniating ability. Among them, strain AB-2 had higher removal efficiency of organic nitrogen than strain AB-1, with removal rate of 83.15% and strain AB-1 67.33%. Compared with other studies, the initial concentration of organic nitrogen in this study is lower, which indicates that the strains selected are indeed effective in degrading organic nitrogen. Recommendations and perspectives The removal rate of organic nitrogen of AB-2 strain isolated in this study can reach more than 83%, which provides a scientific basis for solving the problem of nitrogen pollution in Taihu Lake and improving the water quality and environment of Taihu Lake. At the same time, it has certain application value to lake eutrophication management. |
| Key words: organic nitrogen ammonifying bacteria isolation and identification degradation effect |
