三维电极生物膜-硫自养耦合脱氮系统中反硝化细菌多样性研究

摘要

With the purpose of uncovering the performance characteristics of three-dimensional biofilm-electrode reactor and sulfur autotrophic coupled denitrification system (3BER-S), a comparative test between 3BER-S reactor and general three-dimensional biofilm-electrode reactor (3BER) was applied. Furthermore, the diversity of denitrifying bacteria in 3BER-S reactor was studied to reveal its denitrifying mechanism by nirS-based clone library. Results show that 3BER-S technology is superior to 3BER technology in TN removal efficiency and buffering pH. The Shannon-Weaver index and Simpson index of denitrifying bacteria in the 3BER-S reactor is 2. 436 and 0. 894, respectively. All the denitrifying bacteria in the 3BER-S system have a high similarity with Beta proteobacteria, and 35 clones (61. 49% ) in the clone library share a relatively high similarity with Thauera; Thiobacillus denitrificans occupy a proportion of 3. 5% ; and 11 clones (19. 29% )share similarity with Acidovorax. This illustrates that the heterotrophic denitrification process plays a dominant role in the denitrifying process of the 3BER-S system when the organic carbon source is sufficient, and hydrogenotrophic denitrification process and sulfur autotrophic denitrification process take account for a certain proportion.%通过对比运行三维电极生物膜-硫自养耦合脱氮系统和常规三维电极生物膜工艺，并运用反硝化基因 nirS克隆文库方法，研究了耦合脱氮系统脱氮性能和反硝化细菌的多样性，为揭示耦合脱氮系统反硝化机理和优化系统运行参数提供参考.研究结果表明：三维电极生物膜与硫自养耦合脱氮系统具有较高的脱氮效率和平衡系统酸碱度的能力.系统中反硝化菌群的 Shannon-Wiener 指数和 Simpson 指数分别为2.436和0.894；Beta proteobacteria在耦合脱氮系统中起主导作用；有35个克隆子(61.49%)与陶厄氏菌属(Thauera)有较高的同源性；脱氮硫杆菌(Thiobacillus denitrifican)的比例为3.5%；11个克隆子(19.29%)与食酸菌属(Acidovorax)有一定的同源性.说明当耦合系统碳源充足时，脱氮作用主要以异养反硝化过程为主，以单质硫和氢为电子供体的自养反硝化脱氮作用也占有一定比例.