采用高通量测序分析全程自养脱氮（CANON）系统不同脱氮效能下的微生物群落结构

从微生物优势菌群构成角度揭示一体式全程自养脱氮反应器(completely autotrophic nitrogen removal over nitrite,CANON)启动、稳态运行及崩溃的微观机理,有助于优化调控微生物种群、增强CANON的脱氮效能.试验采用序批式反应器(sequencing batch reactor,SBR),以间歇曝气方式启动CANON系统(35℃±1℃),考察了CANON系统从启动、稳定到恶化过程的氮素转化率和微生物活性;同时对污泥样品采用16S rDNA宏基因组高通量测序技术,考察种泥和不同脱氮效能时期的微生物种群结构.试验结果表明:本CANON系统的厌氧氨氧化菌(anaerobic ammonium oxidation bacteria,AnAOB)为Candidatus Kuenenia,氨氧化菌(ammonium oxidation bacteria,AOB)和硝化菌(nitrite oxidation bacteria,NOB)分别为亚硝化单胞菌属(Nitrosomonas)和Uncultured Nitrospinaceae;系统启动时,AnAOB丰度达到0.44%,AOB和NOB分别占总菌的27.61%和1.33%,脱氮效果最佳时的总氮容积去除率达到218.0 mg/(L·d);由于系统溶解氧质量浓度较低(0.15~0.25 mg/L),好氧段发生厌氧氨氧化反应,好氧段结束时亚硝氮积累量持续下降,导致缺氧段亚硝酸盐基质不足,AnAOB受到抑制;长期运行条件下,反应器内生物多样性及AnAOB丰度均有所下降.反应末期,Nitrosomonas占总菌群数量的62%,成为优势菌种,而AnAOB仅占0.13%,与此时较低的总氮容积去除率(19.3 mg/(L·d))相吻合.

Microbial Community Characteristics of a Completely Autotrophic Nitrogen Removal Over Nitrite (CANON) System Based on High-throughput Sequencing Technology

Research achievements regarding bacterial community dynamics of completely autotrophic nitrogen removal over nitrite ( CANON ) systems are helpful to improve the understanding of biological nitrogen removal processes and to better operation control. In this study, a lab-scale one stage nitritation-anaerobic ammonium oxidation ( Anammox) sequence batch reactor ( SBR) was operated at 35℃ ± 1℃under a regime of intermittent aeration. The full life cycle of a starting-up progress was studied, which covered a start-up phase, a quasi-steady-state phase and a final deterioration phase. High-throughput sequencing technology was employed to identify the microbial communities in different stages. The highest volumetric nitrogen removal rate of 218. 0 mg/(L·d) was obtained after two weeks of start-up. 16S rDNA sequencing analysis revealed that the three functional bacteria took different proportions related to the total bacteria, i. e. , 0. 44%, 27. 6% and 1. 33% for anaerobic ammonium oxidation bacteria ( AnAOB ) , ammonium oxidation bacteria ( AOB ) and nitrite oxidation bacteria ( NOB ) respectively. Anammox process occurred in the aeration phase due to the low dissolved oxygen, resulted in the gradual decline of the accumulated NO2--N at the end of the aeration phase. While at the last phase of the anoxic, AnAOB was suppressed for the depletion of NO2--N. At the end of the operating life cycle, Nitrosomonas established a stable foothold in the community (62%) , while the AnAOB species only occupied 0. 13%, which agreed well with the declined total nitrogen removal rate (19. 3 mg/( L·d) ) .