一株异养硝化-好氧反硝化菌Bacillus flexus X1-L的分离鉴定及效能研究

近年来，随着中国经济的快速发展，水体中氨氮超标问题已严重影响到人类身体健康和生态环境平衡，有效去除水体中的氨氮已成为人们研究的热点.在传统污水生物脱氮处理中，常采用微生物的硝化、反硝化作用去除污水中的氮素，从而降低对环境的污染.本文从活性污泥反应器中分离出一株异养硝化-好氧反硝化菌株，并命名为X1-L.菌体经形态学观察、生理生化测定及16S rRNA基因序列分析，确定属于芽孢杆菌属（Bacillus sp.），Genbank登录号为MT457091，并利用MEGA7.0软件建立了相应的系统发育树.在以NH₄⁺-N为唯一氮源的条件下，菌株X1-L生长较好，COD去除率为96.4%，氨氮去除率达到99.6%，经硝化作用去除的氮有43.7%，证明菌株X1-L具有异养硝化能力.在以NO₂^--N或NO₃^--N为唯一氮源的条件下，菌株X1-L生长也较好，COD去除率分别为95.3%和96.4%，NO₂^--N和NO₃^--N去除率分别为95.5%和96.5%，经反硝化作用去除的氮分别有67.7%和68.2%，证明菌株X1-L具有好氧反硝化能力.

Isolation and characterization of a heterotrophic nitrification-aerobic denitrification strain Bacillus flexus X1-L

In recent years, with the rapid development of China''s economy, the problem of excessive ammonia nitrogen in water seriously affects human health and the balance of ecological environment, and the effective removal of ammonia nitrogen in water has always been the focus of people''s research. In the traditional biological denitrification treatment of wastewater, the nitrification and denitrification of microorganisms are often used to remove nitrogen in wastewater, so as to reduce environmental pollution. In this paper, a heterotrophic nitrifying-aerobic denitrifying strain was isolated from an activated sludge reactor and named X1-L. Through morphological observation, physiological and biochemical determination and 16S rRNA gene sequence analysis, the bacteria were identified as Bacillus sp., and the Genbank login number was MT457091. MEGA7.0 software was used to establish corresponding phylogenetic trees. Under the condition of NH₄⁺-N as the sole nitrogen source, strain X1-L grew well, COD removal rate was 96.4%, ammonia nitrogen removal rate reached 99.6%, nitrogen removal rate by nitrification was 43.7%, proving strain X1-L had heterotrophic nitrification ability. Under the condition of NO₂^--N or NO₃^--N as the sole nitrogen source, X1-L strain grew well, COD removal rates were 95.3% and 96.4% respectively, NO₂^--N and NO₃^--N removal rates were 95.5% and 96.5% respectively, nitrogen removal by denitrification was 67.7% and 68.2%, proving that X1-L strain had aerobic denitrification ability.