一株荧光假单胞杆菌的分离鉴定与反硝化特性

【目的】从污水厂的活性污泥中获得一株高效反硝化细菌。【方法】采用低温驯化,进行初筛、复筛选取一株反硝化活性最高的菌株,命名为L2,通过形态学、生理生化特征及16S r RNA基因序列分析研究其分类地位,系统研究理化因素对该菌株反硝化性能的影响。【结果】菌株在低温条件下能够稳定高效地进行反硝化,鉴定该菌株为荧光假单胞杆菌(Pseudomonas fluorescens),其反硝化最适接种量为10%,温度为20°C,p H为7.0,盐浓度为0.5%,碳源为葡萄糖,C/N为5.0,能够耐受较高初始硝态氮浓度。【结论】菌株L2是一株耐低温、耐高浓度初始硝态氮、耐低C/N、兼性厌氧、高效反硝化的荧光假单胞杆菌。

Identification and characterization of a denitrifying bacterium Pseudomonas fluorescens

Objective] In order to isolate a bacterium, with high efficiency denitrifying, from activated sludge samples. Methods] The strain, was named L2, isolated through domestication enrichment, purification, preliminary and secondary screening, which was identified based on its morphology characteristics, and 16S rRNA gene sequence analysis. we systematic studied its various denitrification characteristics as follows: inoculation volume, temperature, pH, salt concentration, carbon source, dissolved oxygen (DO), carbon nitrogen ratio (C/N) and initial nitrate concentration. Results] The strain was identified as Pseudomonas fluorescens, and the results showed that the most suitable denitrification conditions of the strain are inoculation volume of 10%, temperature of 20 °C, with the poor thermal stability, pH of 7.0, salt concentration of 0.5%, carbon source of glucose, C/N of 5.0, and it can tolerate high initial nitrate concentration. Conclusion] This Pseudomonas fluorescens, which had good resistance to low temperature, high tolerance to initial nitrate concentration, tolerance low carbon nitrogen ratio, was a facultative anaerobic efficient denitrifying bacterium.