一株异养型亚硝酸盐氧化细菌的分离及其降解特性的研究

Isolation,Identification and Characterization of a Nitrite-oxidizing Bacterium

以亚硝酸盐和琥珀酸钠作为惟一氮、碳源从活性污泥中筛选分离一株能够高效氧化亚硝酸盐的硝化菌株,并对其形态学、生理生化及16S rDNA同源性进行分析,在此基础上研究pH、温度、转速、初始亚硝基氮的浓度以及盐浓度对其氧化亚硝酸盐的影响。结果显示,在好氧条件下,该菌株能在12 h内将356.004 mg/L亚硝酸盐降解99.53%。根据形态学特征、生理生化特性以及16S rRNA同源性分析,初步将该菌株鉴定为施氏假单胞菌(Pseudomonas stutzeri),并将其命名为LYS-86。该菌株氧化亚硝酸盐的最适pH8.0-10.0,温度30℃,转速180 r/min,盐浓度1 g/L。当培养基中初始亚硝酸盐浓度为0.5 g/L时,菌株LYS-86的硝化活性最高,随着培养基中初始亚硝基氮浓度的不断提高,菌株LYS-86的硝化活性会不断下降。本研究利用硝化细菌选择性培养基从活性污泥中筛选到了一株异养型亚硝酸氧化菌菌株,该菌株具有高效的硝化活性,为今后该菌株的实际应用及理论研究奠定了基础。

A heterotrophic nitrite-oxidizing strain with high nitrite-oxidizing activity was intended to be isolated from activated sludge and its optimum culture conditions for oxidizing nitrite were investigated to provide guidance for Industrial microbial wastewater treatment. Using nitrite and sodium succinate as the sole carbon and nitrogen sources, a nitrifying strain with highly nitrite-oxidizing activity was isolated from activated sludge, the morphological, physiological, biochemical properties and 16S rDNA homology analysis of which were investigated. In addition, the influence of pH, temperature, shaking speed, the initial concentration of nitrite, salt concen- tration and different carbon sources on nitrite oxidation was also studied. Results showed that a nitrite oxidizing strain was isolated from activated sludge. The nitrite removal efficiency was up to 99. 53% within 12 h under the aerobic conditions with the initial NO2-N con- centration of 356. 004 mg/L. According to its morphological, physiological-bioehemieal characteristics and 16S rDNA homology, this strain was identified as Psettdomonas stutzeri and named LYS-86, and the optimal conditions of culture were determined, including optimal temperature 30℃ , pH8.0 - 10.0, and salt concentration 1 g/L, respectively. In addition, the nitrification activity of this strain was greatly inhibited when initial NO2-N concentration in medium was high. Therefore, it proved that the heterotroph nitrite-oxidizing strain selected from activated sludge had high nitrification activity and could be used for future industrial purpose.