从不同反应器筛选、鉴别好氧反硝化菌

采用2个序批式反应器A和B，以硝态氮为唯一氮源，采用间歇曝气，以驯化、富集耐氧脱氮污泥.反应器A，其pH约为6.3，ρ(DO)为2.2～6.1 mg/L，碳氮比(ρ(C)/ρ(N)，ρ(C)以ρ(COD_Cr)计)约为9；反应器B，其pH约为6.8～7.8，ρ(DO)为 2.2～3.0 mg/L，ρ(C)/ρ(N)约为15.2个反应器的ρ(NO₃－-N)均保持为80 mg/L.当2个反应器的总氮去除率达到60%以上，则认为完成好氧反硝化菌的富集.从2个反应器中共筛选得到20株BTB阳性菌，其中8株菌株的DNA样品经PCR成功扩增，进行16S rRNA测序.测序结果提交GenBank进行Blast同源性检索，并分析比对鉴别，判断8株菌株分属于假单胞菌(Pseudomonas)，戴尔福特菌(Delftia)，草螺菌(Herbaspirillum)和丛毛单胞菌(Comamonas)菌属.反硝化性能测定证实8株菌株均为好氧反硝化菌. 

Selection and Identification of Aerobic Denitrifiers from Different Reactors

By adopting two sequence batch reactors, Reactors A and B, nitrate as substrate, using intermittent aeration mode, the aerotolerant nitrogen removal sludge was domesticated and accumulated. In Reactor A, pH was approximately 6.3, DO 2.2～6.1 mg/L, ρ(C)/ρ(N) 9; and in Reactor B, pHwas 6.8～7.8, DO 2.2～3.0 mg/L, ρ(C)/ρ(N) 15. Both reactors kept the influent nitrate concentration at 80 mg/L. When TIN removal efficiency of both reactors reached 60%, the accumulation of aerobic denitrifiers was regarded as completed. Twenty BTB positive bacteria were isolated from two SBR reactors and 8 DNA samples of them were amplified by PCR and processed for 16S rRNA sequence. Obtained results were processed through Blast similarity search by GenBank, analyzed through genetic tree and compared through identification. As a result, the 8 bacteria belong to genus Pseudomonas, Delftia, Herbaspirillum and Comamonas, respectively. These 8 bacteria were all aerobic denitrifiers by denitrifying measurement. Atpresent, no Delftia has been reported as aerobic denitrifier.