好氧反硝化菌T7用于废水脱氮特性的研究

Study on Nitrogen Removal Characteristics of an Aerobic Denitrifying Bacterium Rhodococcus Strain T7

从具有同时硝化反硝化(SND)现象的OGO反应器中分离出一株脱氮活性较高的好氧反硝化菌,命名为菌株T7,分离菌株革兰氏染色为阳性,形状为杆状,颜色为粉红,经PCR扩增后测定该菌株的16SrDNA基因序列,由16SrDNA基因序列比较可知T7为赤红红球菌属(Rhodococcus)。菌株在柠檬酸钠为唯一碳源、硝酸钾为唯一氮源的培养基中生长良好,且最佳C/N比为5。将其扩大培养后对硝酸盐氮与亚硝酸盐氮为唯一氮源的模拟废水进行处理,选用聚乙烯醇(PVA)作为包埋载体,将接种菌做成固定化的小球,再将其投放于不同浓度的模拟废水中,同时与未包埋时的处理效果进行比对。试验结果表明:该菌株能在好氧的条件下代谢硝酸盐氮与亚硝酸盐氮,可以处理不同浓度的硝酸盐氮与亚硝酸盐氮的废水,且PVA包埋菌泥的投放方式为好氧反硝化菌的工程应用提供更有利的条件。

One strain of aerobic denitrifying bacterium ,named as T7 ,with high activity of nitrogen removal was isolated from OGO reactor possessing simultaneous nitrification and denitrification （SND） phenomenon, T7 is Grampositive , rod-like and pink and identified as Rhodococcus according to its PCR amplification and 16SrDNA sequence homology comparison. It could grow well with potassium nitrate as only nitrogen source and sodium citrate as only carbon source, and optimum ratio of C/N was five. The amplification culture of this bacterium was used in synthetical nitrate wastewater treatment, and polyvinyl alcohol （PVA） was selected as entrapment carrier to immobilize T7. The experimental results indicate that the bacterium can metabolize nitrate when sufficient oxygen exists, and can treat different concentrations of nitrogen-containing wastewater. Besides, the mode of dropping bacteria immobilized by polyvinyl alcohol（PVA） can provide advantage conditions for engineering application of aerobic denitrifying bacteria.