高效氨氮降解菌株的筛选及其降解条件优化

Screening of Efficient Ammonia-nitrogen-degrading Strains and Optimization of the Degradation Conditions

水体中N、P等营养盐的过多引起的水体富营养化严重破坏了生态系统的平衡.本文以(NH4)2SO4为唯一氮源,自活性污泥中分离得到36株氨氮降解菌,经过菌种复筛,获得氨氮降解率最高的一株菌:AD-7,经分子生物学鉴定该菌株为Galactomyces属.以初始氨氮浓度、接种量和pH为唯一变量进行单因素实验,并依据单因素实验结果进行Box-Behnken设计,利用响应面法分析三个因素之间的交互作用及确定最适的氨氮降解条件.结果表明,该菌株在三个因子多个不同配比情况下氨氮降解率均在99%及以上,并在pH 5.59,初始氨氮浓度291.16 mg/L,接种量2.21%时氨氮降解率预测值为100%,实测值仍可达到99%.本研究结果对含氨氮污水处理过程中菌种的使用及各因素之间的调节具有重要的指导意义.

The eutrophication caused by excessive N,P and other nutrients in the water body has seriously damaged the balance of the ecosystem.In this paper,36 strains of ammonia-nitrogen-degrading bacteria were isolated from activated sludge using(NH4)2SO4 as the sole nitrogen source.After re-screening of strains,a strain with the highest ammonia-nitrogen degradation rate was obtained:AD-7,which was identified as Galactomyces by the method of molecular biology.The single factor experiment was conducted with the initial ammonia nitrogen concentrations,inoculum doses and pH as the only variable,and the Box-Behnken design was carried out based on the results of single factor experiment.The response surface method was used to analyze the interaction between the three factors and determine the optimal ammonia nitrogen degradation conditions.The results showed that the ammonia nitrogen degradation rate of this strain was 99%or more at different ratios of three factors.At the condition of pH 5.59,initial ammonia nitrogen concentration 291.16 mg/L,and inoculation doses 2.21%,the ammonia nitrogen degradation rate could still be reached to 99%.The experimental results in this paper will have important guiding significance for the use of strains and adjustment of various factors in the treatment process of wastewater containing ammonia nitrogen.