异养硝化–好氧反硝化细菌X₃的氮形态响应

Response to Different Nitrogen Forms of Heterotrophic Nitrifying-Aerobic Denitrifying Bacteria X₃

摘要: 异养硝化–好氧反硝化细菌的氮响应机制对研究生物脱氮技术具有重要意义。通过分析异养硝化–好氧反硝化细菌X3 (Halomonas alkaliphila)生化周期与培养液中氮形态的关系，对该菌的脱氮机制进行了研究。结果表明：1) 含混合形态氮培养液中，细菌X₃在对数生长期主要进行有机氮的降解；整个周期中，氨氮先升高后降低，48 h达到最高值，亚硝酸氮先升高后降低，第4天达到最高值，硝酸氮表现为先下降，48 h后上升的变化趋势，96 h总氮去除率为17.07%；2) 仅含无机氮的培养液中，细菌X₃在对数生长期主要进行氨氮和硝酸氮的降解；整个周期中，氨氮和硝酸氮持续下降，亚硝酸氮先升高后降低，24 h达到最高值，96 h总氮去除率可达51.13%。结论：细菌X₃的氮降解优先顺序和最终效能皆受控于环境氮化合物形态。本研究有望为生物脱氮工程设计提供理论指导。

Abstract: For the development of biological denitrification technique, study on the response mechanism of heterotrophic nitrifying-aerobic denitrifying bacteria to nitrogen forms has great significance. Herein the relationship between the nitrogen form and the denitrification activity of Halomonas alkaliphila X₃ was studied by monitoring the change of different nitrogen forms in the culture so-lution, and the results are as follows. 1) In the culture solution containing both organic nitrogen and inorganic nitrogen, Halomonas alkaliphila X₃ mainly degrades organic nitrogen during the logarithmic growth period. Over the whole culture cycle, the concentration of ammonia nitrogen rises up in the first 48 h, followed by a decreasing trend; the concentration of nitrite nitrogen rises up in the first 4 d, followed by a decreasing trend; while the concentration of nitrate nitrogen de-creases in the first 48 h, followed by a decreasing trend. In total 17.07% nitrogen is removed from the culture solution after a treatment for 96 h. 2) In the culture solution containing only inorganic nitrogen, the bacteria mainly degrades ammonia nitrogen during the logarithmic growth period. Over the whole culture cycle, the concentration of ammonia and nitrate nitrogen keeps down; the concentration of nitrite nitrogen rises up in the first 24 h, followed by a decreasing trend. In total 51.13% nitrogen is removed from the culture solution after a treatment for 96 h. In conclusion, the priority and efficiency of the nitrogen degradation by Halomonas alkaliphila X₃ both depend on the initial nitrogen forms in the culture solution. These outcomes are promising to help the construction of biological denitrification engineering.