一株脱氮菌的氮代谢路径研究

Study on the Nitrogen Metabolism Pathway of a Denitrifying Bacteria

从环境中筛选出一株异养硝化-好氧反硝化门多萨假单胞细菌P.mendocina L2,通过实验发现L2细菌的生长和脱氮最适碳源为柠檬酸钠,最适C/N为15,最适培养温度为30℃,最适培养转速为200 r/min,最佳接种量为1%。其在该条件下能够使用氨氮、亚硝态氮和硝态氮作为反应底物进行硝化或反硝化反应,48 h后总氮去除率达40%以上。使用分子生物学手段从L2细菌中扩增出氮转化途径相关基因,推测菌株L2的完整硝化及反硝化路径为NH_(4)^(+)→NH_(2)OH→NO_(2)^(-)→NO_(3)^(-)→NO_(2)^(-)→NO→N_(2)O→N_(2),为异养硝化-好氧反硝化现象发生机理的研究提供参考。

In this paper,a heterotrophic nitrifying-aerobic denitrifying Pseudomonas mendocina L2 strain was screened from the environment.It was found that the optimal carbon source for the growth and denitrification of L2 bacteria was sodium citrate C/N was 15,the optimum culture temperature was 30℃,the optimum culture speed was 200 r/min,and the optimum inoculation amount was 1%.Under these conditions,ammonia nitrogen,nitrite nitrogen and nitrate nitrogen can be used as reaction substrates for nitrification or denitrification reaction,and the total nitrogen removal rate is over 40%after48 h.The genes related to the nitrogen conversion pathway were amplified from L2 bacteria by molecular biology methods,and the complete nitrification and denitrification pathways of strain L2 were speculated to be:NH_(4)^(+)→NH_(2)OH→NO_(2)^(-)→NO_(3)^(-)→NO_(2)^(-)→NO→N_(2)O→N_(2).It provides a reference for the study of the mechanism of heterotrophic nitrification-aerobic denitrification.