CANON系统中4种脱氮相关菌丰度和多样性

Abundance and Diversity of Four Nitrogen Removal Microbes in Completely Autotrophic Nitrogen Removal Over Nitrite(CANON) Systems

全程自养脱氮(Completely Autotrophic Nitrogen removal Over Nitrite,CANON)是适用于低碳源、高氨氮水质的极具应用前景的新工艺,研究其中脱氮微生物种群和数量特征具有重要意义.利用PCR、克隆、实时荧光定量PCR等分子生物学技术,研究了小试(Lab-scale,L)和中试(Pilot-scale,P)2个CANON系统中4种与脱氮相关的细菌(分别是氨氧化细菌(Ammonia-Oxidizing Bacteria,AOB)、亚硝酸盐氧化菌(Nitrite-Oxidizing Bacteria,NOB)、反硝化细菌(De Nitrifying Bacteria,DNB)和厌氧氨氧化细菌(ANaerobic AMMonium Oxidation,Anammox))的数量和种属,并研究了污泥形态对这4种菌的数量影响.结果发现,(1)L和P系统中AOB、NOB、DNB和Anammox菌数量均值分别处于1010、109、108和1010copies/g(以干污泥计)数量级.AOB和Anammox菌是CANON系统的优势菌,而NOB和DNB数量较少.(2)AOB、NOB、DNB和Anammox菌多样性不同:DNB种属最丰富,10多个属划分为5大簇;其次是Anammox菌,主要划分为Candidatus Brocadia和Candidatus Kuenenia 2簇;再次是AOB,集中在Nitrosomonas属中的N.europaea和N.eutropha 2小簇;最后是NOB,它的种属最为单一,仅含Nitrospira marine小簇.(3)污泥形态不同影响这4种菌数量:絮体污泥更适合AOB生长,生物膜更适合DNB和Anammox菌生长,但不能确定哪种形态的污泥更适合NOB生存.研究结果将为CANON系统的脱氮机理揭示和工艺优化提供理论支撑.

Completely autotrophic nitrogen removal over nitrite( CANON) was an innovative nitrogen removal process,especially for ammonia-rich and low COD concentration wastewater,so it was meaningful to investigate the microbial ecology of nitrogen removal bacteria in CANON system.Polymerase chain reaction( PCR),cloning and real-time PCR( q PCR) techniques were applied to investigate the abundance and diversity of AOB,NOB,DNB and anammox bacteria in two CANON systems. The effect of different sludge form on their abundance was also studied.q PCR results showed that the average abundance of AOB,NOB,DNB and anammox bacteria were in the orders of magnitude of 1010,109,108 and 1010copies / g dry sludge,respectively,which indicated that AOB and anammox bacteria were the most abundant species and played major roles in nitrogen removal in CANON system. For diversity analysis,DNB was in greatest diversity,being divided into five clusters and attributed to a total of more than ten genera; The anammox bacteria was of less diversity and mainly belonged to Candidatus Brocadia cluster and Candidatus Kuenenia cluster; AOB was attributed to N. europaea cluster and N. eutropha cluster of Nitrosomonas group. However,for NOB,only Nitrospira marine cluster appeared. The sludge form,flocculent activated sludge and biofilm,also affected their abundance. Flocculent activated sludge was more suitable for the growth of AOB,biofilm was more suitable for the growth of DNB and anammox bacteria; However,it was unclear which kind of sludge form was favorable for the growth of NOB. This study provided microbial foundation for optimizing CANON system to improve nitrogen removal efficiency.