两株异养硝化细菌的分离鉴定及其脱氮特性

Screening and identification of two heterotrophic nitrifying bacteria and characterization of their capacity for nitrogen removal

摘要:

摘要:【目的】利用异养硝化培养基，从华中农业大学实验猪场污水中筛选得到2 株具有较高脱氮效率的细菌。【方法】通过形态学特征及16S rDNA 序列的系统发育分析，对分离菌株进行了鉴定。且对菌株P2 和P9降解氨氮的相关特性也作了研究。此外，将菌株单独或混合接种于猪场污水，检测其处理实际污水的脱氮效果。【结果】初步判断菌株P2 为副球菌属(Paracoccus sp.)，P9 为申氏杆菌属(Shinella sp.)。2株细菌能在有机物存在下进行异养硝化作用，经24h 培养，菌株P2 和P9 对氨氮的去除率可达80% 左右，同时未发现亚硝酸盐、硝酸盐积累;但菌株P2，P9不能以NO－3或NO－2为唯一氮源发生好氧反硝化作用。菌株P2 和P9异养硝化的最适碳源为丁二酸钠，最适C /N 比为9，且脱氮过程中pH 值从6.8到8.9 一直呈上升趋势。菌株对小分子碳源具有较强的依赖性，在加入小分子碳源的情况下，其对污水具有较强的脱氮能力，且这两个菌株混合施用较单独作用氨氮去除效果更好。【结论】菌株P2 和P9 脱氮能力较强，其在污水处理行业具有重要的应用前景。

Abstract:

Abstract:［Objective］ Two heterotrophic nitrifying bacteria，P2 and P9 isolated from piggery wastewater，were studied for their capacity of nitrification and nitrogen removal． ［Methods］ Physiological characteristics and phylogenetic analysis based on 16S rDNA sequences of strains P2 and P9 were analyzed． The ammonia removal characteristics of strains P2 and P9 were investigated． Furthermore，nitrogen removal ability of strains P2 and P9 individually or mixed were evaluated in the treatment of actual piggery wastewater． ［Results］ Strains P2 and P9 were identified as Paracoccus sp． and Shinella sp.,respectively． Heterotrophic nitrification could occur by the strains when they utilized organics． After cultivation of 24 h，the ammonia removal rates by the strains were up to 80% approximately; meanwhile，there was almost no nitrite and nitrate accumulation． However，aerobic denitrification could not occur by the strains when NO－3 or NO－2 was provided as the sole nitrogen source，respectively．For heterotrophic nitrification，with strains P2 and P9，the optimal carbon source was sodium succinate，and the optimal C /N ratio was 9． Besides，the pH values rose from 6.8 to 8.9 in the whole ammonia removal process． The growth and nitrogen removal ability of the two strains depended much on the quantity of small molecule carbon source，and the nitrogen removal capability of strains P2 or P9 in wastewater with small molecule carbon source was improved evidently． The effect was strengthened especially when the two strains were mixed together．［Conclusion］ Nitrogen removal ability of strains P2 and P9 was relatively strong，and they may exhibit broad application prospects in wastewater treatment．