一株好氧反硝化菌的鉴定及脱氮特性研究

以筛选分离得到的好氧反硝化菌HG-7为研究对象, 经过16S rRNA同源性分析, 初步鉴定该菌株为假单胞菌属(Pseudomonas sp.)。对菌株HG-7反硝化功能基因的扩增结果表明, 菌体HG-7内存在好氧反硝化功能基因napA和nirK, 证实该细菌为好氧反硝化细菌。对菌株的脱氮特性和影响因素的研究表明, 以硝酸盐氮为氮源时, 菌株的最适碳源为乙酸钠和丁二酸钠, 最佳C/N比为6~10, 最适宜的温度范围为26~30℃。在上述条件下, 菌株HG-7的好氧反硝化活性较高, 48小时内对100 mg/L硝酸盐氮的去除率可达98%, 且在反应过程中亚硝酸盐氮积累量较低。以亚硝酸氮为唯一氮源时, 低浓度条件下可实现100%的氮素去除率; 高浓度条件下, 脱氮速率则受到明显的抑制, 对91.4 mg/L的亚硝酸盐氮氮去除率约为40%。因此, 将该菌株应用于废水的脱氮处理, 可实现氮素的有效去除, 具有潜在的应用价值。

Identification of an Aerobic Denitrifier and Its Denitrification Characteristics

Strain HG-7 was identified as Pseudomonas sp. through 16s rRNA gene sequence analysis. The aerobic denitrification ability of strain HG-7 was further proved by the existence of the napA and nirK genes. Further studies showed that the optimal carbon resources for strain HG-7 were sodium acetate and sodium succinate, the optimal C/N ratio was 6?10, and the suitable temperature was 26?30℃. At this condition, with an initial nitrate nitrogen of 100 mg/L, 98% of nitrate could be removed in 48 hours and the amount of nitrite accumulation was very small. Moreover, with nitrite as the sole nitrogen source, 100% of nitrite could be removed at lower nitrite concentration. But the nitrite nitrogen removal rate was about 40% when the nitrite concentration increased to 91.4 mg/L, indicating that high nitrite concentration was harmful for aerobic denitrification by strain HG-7. The strain HG-7 has great potential to be used for biological nitrogen removal, which was particularly significant for actual wastewater treatment processes.