中高温污泥厌氧消化系统中微生物群落比较

A comparative study of microbial community compositions in thermophilic and mesophilic sludge anaerobic digestion systems

【目的】结合中温与高温消化两者优势的两相厌氧消化工艺可能是推进污泥厌氧消化发展的重要方向,因此,探究和比较中温和高温污泥厌氧消化系统中微生物群落组成的异同具有重要意义。【方法】利用高通量测序技术检测中温和高温厌氧消化系统中细菌与古菌的16S r RNA基因序列信息和真菌的内转录间隔(ITS)序列信息,利用基因芯片(Geo Chip 5.0)检测病毒和病原菌致病基因的信息,以对比中温和高温条件下微生物群落在物种组成和功能基因层面上的异同。【结果】中温和高温条件下细菌和古菌在群落物种组成上存在显著差异,病毒和病原菌毒性基因也显著不同,而两种系统中真菌群落的物种组成相似且丰度相对较低。中温条件下产甲烷古菌和未分类微生物相对丰度较高,而高温条件下产酸及嗜热菌相对丰度较高,且高温消化后病毒和病原菌毒性基因相对丰度下降。微生物群落结构与COD、TS和VS有着显著相关性。【结论】微生物群落组成和功能基因在中高温的污泥厌氧消化系统中显著不同,从而解释了两个系统功能的差异。微生物群落的形成与进水参数相关,说明微生物对进水条件敏感。

[Objective] Two-stage thermophilic and mesophilic sludge anaerobic digestion process, which combines the processes of thermophilic digestion and mesophilic digestion, is a potentially important strategy for the development of sludge anaerobic digestion. Thus, it is necessary to investigate and compare the microbial community compositions in thermophilic and mesophilic anaerobic digestion systems. [Methods] Based on high-throughput sequencing and Geo Chip techniques, we checked the 16 S r RNA gene sequences of bacteria and archaea, ITS sequences of fungi and virus and virulence genes in anaerobic digestion systems, then compared the taxonomic and functional compositions between thermophilic and mesophilic microbial community. [Results] The taxonomic compositions of bacteria and archaea and the functional compositions of virus and virulence differed significantly between thermophilic and mesophilic anaerobic digestion systems, while the fungal taxonomic compositions were similar and the sequence reads number were relatively low. Methanogenus and unclassified bacteria and archaea were more abundant in mesophilic condition, while acid-producing and thermophilic microbes were more abundant in thermophilic condition. The relative abundance of genes associated with virus and virulence decreased after thermophilic digestion. In addition, microbial community compositions were significantly correlated with COD, TS and VS. [Conclusion] Microbial community compositions were significantly different between thermophilic and mesophilic anaerobic digestion, which explained functional distinction between the two ecosystems. The succession of microbial community was associated with influent parameters, revealing an important sensitivity.