河南省白龟山水库下游水体氨化细菌分离鉴定及其降解有机氮条件

Isolation and identification of ammonifying bacteria in the downstream waters of Baiguishan Reservior in Henan Province and conditions of degrading organic nitrogen

摘要:

【目的】从河南省白龟山水库下游水体中分离筛选氨化细菌，并研究其降解有机氮的条件。【方法】利用选择性培养基从微污染水源水中筛选氨化细菌，进一步比较了不同氨化细菌降解有机氮的效果；采用单因子法研究菌株N24降解有机氮的条件；通过形态、生理生化特征及16S rRNA 基因序列分析对菌株N24进行鉴定。【结果】从微污染水源水中分离筛选到4株氨化细菌，其中菌株N24培养48 h后氨氮浓度较高，达到138.926 mg/L。菌株N24降解有机氮最适温度为30?35 °C，最适初始pH值为6.0，500 mL摇瓶最适装液量75 mL。菌株N24被鉴定为弯曲芽孢杆菌(Bacillus flexus，GenBank登录号：JX291240.1)，其16S rRNA基因序列与基因库中芽孢杆菌属菌株的16S rRNA基因序列有99%?100%的相似性，与弯曲芽孢杆菌(Bacillus flexus IFO15717T，GenBank登录号：NR024691.1)的遗传距离最近。【结论】菌株N24是一株高效降解有机氮的弯曲芽孢杆菌；本研究丰富了降解有机氮菌种资源，可为该菌在环境工程领域的实际应用提供理论基础。

Abstract:

[Objective] The aims of the present study were to isolate and screen ammonifying bacteria, and to examin the conditions for their degradation of organic nitrogen. [Methods] Ammonifying bacteria were isolated from the micro-polluted raw water collected from the downstream water bodies of the Baiguishan Reservoir in Henan Province. The obtained nitrifying bacteria were studied for their capabilities to degrade organic nitrogen; The conditions for strain N24 to remove organic nitrogen were assessed by using single factor method. Strain N24 was identified by morphology, physiological and biochemical characteristics, and 16S rRNA gene-base phylogenetic alalyses. [Results] Four ammonifying bacterial strains were isolated from the collected water samples, The NH4+-N concentration reached 138.926 mg/L after 40 hours’ fermentation of strain N24. The optimal conditions for strain N24 to remove organic nitrogen were about 30?35 °C, initial pH 6.0, and medium volume 75 mL. Strain N24 was identified as Bacillus flexus (GenBank accession number: JX291240.1). Its 16S rRNA gene sequence had 99%?100% similarity with those of Bacillus sp. deposited in GenBank, and showed closest relatedness to Bacillus flexus IFO15717T (GenBank accession number: NR024691.1). [Conclusion] N24 is an efficient organic nitrogen-degrading Bacillus flexus; The present study enriched the microbial resources for organic nitrogen removal and provided a theoretical framework for the practical use of strain N24 in environmental engineering.