耐碱反硝化菌株的分离鉴定与功能检测

Identification and function test of an alkali-tolerant denitrifying bacterium

摘要:

摘要:【目的】分离获得耐碱反硝化菌株，确定其反硝化活性和耐碱能力。【方法】分离、纯化，获得耐碱反硝化菌株;通过形态观察、生理生化试验和16S rRNA基因测序分析，确定菌株分类地位;试验起始硝酸盐浓度和起始pH 对分离菌株反硝化活性的影响。【结果】从实验室稳定运行的高效反硝化反应器中分离获得耐碱反硝化菌株R9，经鉴定归于Diaphorobater nitroreducens;菌株R9能够以甲醇为电子供体、硝酸盐为电子受体进行异养生长，当起始硝氮浓度为50 mg/L、起始pH为9.0 时，288 h内硝氮去除率达93.25%;高浓度硝氮可抑制其反硝化活性，半抑制常数Ki为202.73 mg N/L;菌株R9的耐碱性良好，起始pH为11.0时的硝氮去除率是pH为9.0时的86%。【结论】菌株R9归于Diaphorobater nitroreducens，最适生长pH为9.0左右，是一株耐碱反硝化菌。

Abstract:

Abstract:［Objective］We obtained an alkali-tolerant denitrifying bacterium，and determined its denitrifying activity and alkali-tolerance． ［Methods］An alkali-tolerant denitrifying bacterial strain was obtained by isolation and purification．We identified the bacterial strain by morphological observation，physiological test and 16S rRNA analysis． We determined the denitrifying activity and alkali-tolerance by effects of initial nitrate concentration and initial pH on denitrification．［Results］An alkali-tolerant denitrifier strain R9 was isolated from the lab-scale high-rate denitrifying reactor，and it was identified as Diaphorobater nitroreducens． The strain R9 grew heterotrophically with methanol as the electron donor and nitrate as the electron acceptor．The nitrate conversion was 93. 25% when strain R9 was cultivated for 288 h with initial nitrate concentration 50 mg/L and initial pH 9.0．The denitrification activity could be inhibited at high nitrate concentration with a half inhibition constant of 202.73 mg N/L．Strain R9 showed a good alkali tolerance with the nitrate removal rate at pH 11.0 remained 86% of that at pH 9.0．［Conclusion］ Strain R9 was identified as Diaphorobater nitroreducens，and it was an alkali-tolerant denitrifying bacterium with optimum pH value of 9.0.