人工湿地高效好氧反硝化菌的分离鉴定及反硝化特性研究

Isolation and Identification of a High -efficiency Aerobic Denitrifier and Its Denitrifying Characteristic in Constructed Wetland

从增氧型复合垂直流人工湿地中采集样品,利用间歇曝气法富集好氧反硝化菌,并进行分离纯化,共得到10株好氧反硝化菌。其中编号为B13的菌株在初始硝态氮含量为277.23mg·L-1、碳氮比为5的条件下,24h的硝态氮去除率达92.80%,亚硝态氮积累只有12.57mg·L-1,脱氮速率达到20.58mg·L-·1h-1。16S rDNA序列分析表明,该菌与Pseudomonas stutzeri同源性达100%。选用四因素三水平L(934)正交试验表设计实验,通过测定对硝态氮去除能力和亚硝态氮的积累量,研究碳源、碳氮比(C/N)、pH以及溶解氧含量(DO)4种不同因素对B13号菌株好氧反硝化性能的影响。结果表明,该菌株对硝态氮的去除率最大可达99.88%,几乎没有亚硝态氮积累。对硝态氮去除率影响最大的因素为碳氮比,其次为pH,溶解氧含量和碳源。对应的最优条件是碳源为葡萄糖,碳氮比为10,pH为9,溶解氧含量为1.84～3.57mg·L-1。

The identification of a Aerobic denitrifier and its practicability for aerobic wastewater treatment in Integrated Vertical-flow Constructed Wetland（IVCW）were studied in this paper.Samples were collected from an aerated IVCW.After enrichment by intermittent aeration,isolation and purification in turn,10 strains of aerobic denitrifiers were obtained and their denitrifying capability were studied in batch culture under aerobic condition.Results showed that the most efficient strain was B13.With initial nitrate concentration of 277.23 mg·L-1,C/ N（carbon/nitrogen）ratio of 5 and an incubation time of 24 h,nitrate removal rate reached 92.80% and nitrite accumulation was in a low concentration of 12.57 mg·L-1.The maximum removal rate of nitrate was 20.58 mg·L-1·h-1.Phylogenetic analysis based on partial 16s rDNA showed that stain B13 had 100% sequence similarity with Pseudomonas stutzeri.An orthogonal experiment by four factors with three levels L（934）was designed to explore the best aerobic denitrification condition for strain B13.The four factors were carbon source,C/N ratio,pH value and dissolved oxygen.Further,results showed that the highest nitrate removal rate was up to 99.88% almost without nitrite accumulation.Thus,strain B13 might be a good candidate for aerobic wastewater treatment.The most important factor on nitrate removal was C/N ratio,followed by pH value,dissolved oxygen and carbon source.The optimized condition for nitrogen removal was C/N ratio of 10,pH of 9 and dissolved oxygen concentration between 1.84～3.57 mg·L-1 with glucose as the carbon source.