一株异养硝化细菌的脱氮特性及其初步应用

Denitriding Characteristic of a Heterotrophic Nitrifying Strain of Bacteria and Its Preliminary Application

氮素超标是导致水体富营养化的重要原因之一，生物除氮是去除水体中氮元素的有效途径。从垃圾填埋场土壤中分离得到菌株WS-2，经16S rDNA鉴定为土壤杆菌（Agrobacterium sp.）。该菌可在42 h内去除95.8%的铵态氮，氮气、硝态氮和细胞内氮为主要产物，分别占初始氮量的42.4%、23.8%和19.4%。同时，该菌可在84 h内去除80.5%的硝态氮和97.1%的亚硝态氮，其中生成的氮气和细胞内氮分别占初始氮量的50.2%～51.0%和17.0%～17.8%。由此可见，菌株WS-2的优势在于不仅可以同步进行硝化和反硝化过程，而且还具有较高的氮气生成率和较低的细胞内氮积累量。进一步将该菌用于处理富营养化水体，发现将菌体固定于聚氨酯载体材料并辅以曝气措施，对CODCr、总氮、铵态氮和总磷的去除率分别可达84.3%、71.3%、94.7%和55.6%，表明该菌具有修复富营养化水体的潜力。

High nitrogen concentration is one of the important causes of water eutrophication. Biological nitrogen removal is an effective way to remove nitrogen from water. A strain of bacteria, coded as WS-2, was isolated from landfill soil and identified as Agrobacterium sp. based on 16S rDNA gene sequencing. The strain could remove 95.8% of the ammonia in the water within 42 h, producing mainly N2, nitrate and intracellular nitrogen, which accounted for 42.4%, 23.8% and 19.4% of the initial nitrogen, respectively. Meanwhile the bacteria could remove 80.5% of the nitrate and 97.1% of the nitrite in the water within 84h, producing N2 and intracellular nitrogen, which accounted for 50.2%-51.0% and 17.0%-17.8% of the initial nitrogen, respectively. It is, therefore, obvious that Strain SW2 bacteria are capable of performing simultaneous heterotrophic nitrification and aerobic denitrification, and during the processes, they turn most ammonia, nitrate and nitrite into gaseous nitrogen and little into intracellular nitrogen. Further experiments of using the bacteria to treat eutrophied water reveal that the bacteria, fixed on polyurethane foams and then subjected to aeration, are capable of removing 84.3%, 71.3%, 94.7% and 55.8%, respectively of CODcr, total nitrogen, ammonia and total phosphorus, which demonstrates that its strain of bacteria has a high application potential in remedying eutrophied water bodies.