柠檬酸废水厌氧颗粒污泥微生物菌群结构解析

Analysis of bacterial community in anaerobic granular sludge for citric acid wastewater treatment

为揭示柠檬酸废水生物处理过程中功能菌群作用机制,以柠檬酸工业废水内循环厌氧反应塔（IC）中厌氧颗粒污泥为研究对象,统计颗粒粒径分布,通过环境扫描电子显微镜（ESEM）观察颗粒微观形态结构,利用高通量测序技术分析微生物多样性及菌群特征.结果发现,粒径在1.0～4.0 mm的颗粒所占比例最多,为74.4%.ESEM显示微生物分布以球形细菌为主.高通量测序得到8 397条有效序列,可划分操作分类单元（OTU）873个,Alpha多样性指数显示样品文库覆盖率0.936,Shannon指数为4.376,而ACE指数与Chao1指数分别为3 415.51与2 246.51,反映颗粒污泥中微生物种类与数量均较多.微生物菌群主要包括4大类,分别为可降解有机物的水解发酵菌群Paludibacter、Parabacteroides、Erysipelotrichaceae、Clostridium、Phascolarctobacterium、Aminobacterium、Saccharofermentans与Alkaliflexus（所占比例之和为24.93%）;产氢产乙酸菌群Petrimonas与Syntrophomonas（所占比例之和为34.89%）;产甲烷菌Methanosaeta（3.44%）及可耐受工业废水毒害的微生物菌群Levilinea、Longilinea与Thermovirga（所占比例之和为14.62%）.

To clarify the performance of functional microorganisms involved in biological citric acid wastewater treatment systems, bacterial community structure of anaerobic granular sludge was investigated in an internal circulation （ IC） anaerobic reactor treating citric acid industry wastewater. Microstructure observation was carried out by environmental scanning electron microscope （ ESEM ） , and the microbial diversity and microfloras were analyzed by high-throughput sequencing. Particle size distribution results showed that the most particles’ diameters ranged from 1.0 mm to 4. 0 mm （ accounted for 74. 4%） . ESEM results showed that spherical bacteria were the dominant microorganisms in granular sludge. The total dataset comprised 8 397 high quality sequences, which could be subdivided into 873 operational taxonomic units. A library coverage of 0. 936 implied that the granular sludge exhibited a high microbial diversity and abundance. The Shannon index, ACE index and Chao1 index were 4.376, 3 415.51 and 2 246. 51, respectively. Genus classification revealed that there were four typical bacterial groups：hydrolytic fermentative bacteria for organic matter degradation were closely related to Paludibacter, Parabacteroides, Erysipelotrichaceae, Clostridium, Phascolarctobacterium, Aminobacterium, Saccharofermentans and Alkaliflexus, which accounted 24. 93% of the bulk bacterial; H2-producing and acetogenic bacteria were correlated with Petrimonas and Syntrophomonas, which accounted for 34. 89%; methanogens of Methanosaeta accounted 3. 44%;and the microflora groups of Levilinea, Longilinea and Thermovirga could be capable of tolerating toxic industrial wastewater, accounting for 14.62% instead.