一株异养硝化-好氧反硝化菌JY78的筛选及其脱氮特性研究

Isolation and identification of JY78,a heterotrophic nitrifying-aerobic denitrification bacterium and its denitrifying features

从水源水库沉积物中筛选出一株高效异养硝化-好氧反硝化细菌JY78,以乙酸钠为碳源,分别以硝酸钠、氯化铵为唯一氮源研究菌株JY78的好氧反硝化、异养硝化特性。结果表明,经过72 h的反硝化过程,JY78对硝氮的去除率达到83.65%,总氮去除率达到58.46%;经过36 h的硝化过程,菌株对氨氮的去除率达到93.53%,总氮去除率达到76.15%。通过形态观察、生理生化分析及16S rRNA测序分析,JY78为不动杆菌Acinetobacter oleivorans。利用响应曲面法研究了p H值、温度、溶解氧和C/N比四因素交互作用对菌株反硝化特性的影响。结果表明,菌株JY78脱氮的最优条件为:C/N比8.0,温度22.57℃,转速37.94 r/min,初始p H值8.15。在此条件下硝氮能够达到最大去除率89.79%。同时,菌株JY78可以耐受低C/N比及低温条件。研究表明,菌株JY78具有突出的异养硝化-好氧反硝化能力,在处理微污染水源水方面具有应用潜力。

The paper is to present its method on how to isolate and identify JY78,a heterotrophic nitrifying-aerobic denitrifying bacterium and its denitrifying features in a source water environmental ecosystem polluted by the nitrogen. As is known,nitrogen pollution of the source water has become more and more serious,especially in the oligotrophic water supply reservoir. To solve the problem,bacteria denitrification has been widely adopted in the nitrogen removing process,though little is known of the behavior of aerobic denitrifying bacteria and their heterotrophic nitrification-aerobic denitrifying ability under the oligotrophic conditions. It is just to expand our idea on the bacteria that we have isolated an aerobic denitrifying bacterial strain from the sediment of a water supply reservoir,which is identified as the bacterial strain JY78 through the morphological observation,physiological and biochemical analysis,known as 16S rRNA sequence and nap A identification. For our research purpose,we have conducted the heterotrophic nitrification and aerobic denitrification experiments by taking CH_3COONa as the sole carbon source,and NH_4Cl and NaNO_3 as the only nitrogen source independently. Through the response surface method,it is possible to obtain the influence of p H,temperature,dissolved oxygen,C / N ratio on the denitrification characteristics of strain JY78. The results show that bacterium JY78 belongs to Acinetobacter oleivorans,whose nap A specificity band reveals the aerobic denitrification characteristics. In the said heterotrophic nitrification process,it is possible for the NH＋4-N removal rate of JY78 to be made as high as 93. 53% through a reaction of 36 hours while the total removal rate of nitrogen（ TN） can be made as high as 76. 15%. At the same time,the NO_3^--N removal rate of JY78 can be made as high as 83. 65% 72 hours later,whereas the TN removal rate tends to reach 58. 46%. Furthermore,we have discovered that the influential degree of the four factors on the nitrate removal rate in a descending denitrification order as follows： pH the temperature C / N the rotating speed. What is more,we have worked out the optimized conditions for the NO_3^--N denitrification by the bacterium JY78 as follows： C / N ratio 8. 0,temperature 22. 6 ℃,rotate speed 38 r / min,and initial pH 8. 2. It is under the aforementioned condition that the maximum removal rate can be made to reach 89. 79% for the nitrate. In addition,JY78 has been found tolerable to the low C / N ratio,low temperature,and the nice heterotrophic denitrification capability,which may lead to the simultaneous nitrification and denitrification,which entails a great application potential in remediating the slightly polluted source water and the reservoir water. Thus,it can be concluded that our research implies a bright prospect for the bioremediation of oligotrophic source water via the aerobic denitrifying bacteria in the engineering application.