猪粪与树叶沼气干式发酵转录水平的微生物群落及丰度

Microbial communities and abundances at transcription level in pig manure and leaf biogas dry fermentation systems

[目的]在转录水平上分别研究猪粪和树叶为基质的沼气干发酵过程中古菌与细菌的类群演替规律,以及甲烷合成关键酶基因mcr A和16S rRNA基因的丰度变化。[方法]通过Barcoded高通量测序获取沼气发酵原核微生物群落组成,利用定量PCR技术获得mcr A和16S rRNA基因丰度,通过皮尔森(Person)指数的计算,分析发酵系统中各微生物类群间的相关性。[结果]猪粪发酵过程细菌和古菌优势类群分别为严格梭菌属(Clostridium sensu stricto1,在不同发酵时期的细菌群落结构占比17%~29%)和甲烷八叠球菌属(Methanosarcina,古菌群落占比19%~79%),树叶发酵为互营单胞菌属(Syntrophomonas,细菌群落占比9%~38%)和甲烷囊菌属(Methanoculleus,古菌占比22%~88%);转录水平上不同发酵时期细菌与古菌的丰富度(Richness)分别在263~462和56~162;每毫升发酵物中mcr A、古菌和细菌的16S rRNA基因拷贝数变化范围分别为2.6×107~1.5×10^(10),3.9×10^(7)~3.3×10^(10),1.2×108~2.1×10^(11)。[结论]皮尔森相关性分析表明了许多类群间的表达丰度存在显著关联;树叶沼气发酵过程始终为氢营养型的甲烷菌主导(在各时期甲烷菌总类群的占比为63%~96%),这同基因组水平的相关研究存在一定差异。

[Objective]To study the transcriptic community structures and abundances of Archaea and Bacteria in the dry biogas fermentation system.[Method]Barcoded high-throughput sequencing was used to reveal the bactetial and archaeal community structures,quantitative PCR was used to obtain mcr A and 16 S rRNA gene abundance,and the Pearson index was calculated to analyze the correlation between the microbial groups.[Result]The dominant bacterial and archaeal genus in pig manure fermentation were Clostridium sensu stricto1(17%-29%of the bacterial transcriptic communities at different fermentation periods)and Methanosarcina(19%-79%of archaeal transcriptic communities),separately.The leaves fermentation was Syntrophomonas(9%-38%of bacterial communities)and Methanoculleus(22%-88%of archaeal communities).At the transcriptional level,the Richness of Bacteria and Archaea in different fermentation periods were 263-462 and 56-162,respectively.The bacterial and archaeal 16 S rRNA gene abundances were from 1.2×10^(8)to 2.1×10^(11)and from 3.9×10^(7)to 3.3×10^(10)copies/m L,respectively;mcr A gene were from 2.6×10^(7)to 1.5×10^(10)copies/m L.[Conclusion]Pearson correlation analysis based on the transcriptic abundance revealed the many significant correlations between different genuses.The leaf biogas fermentation was always dominated by hydrogentrophic methanogens(63%-96%of total methanogenic communities),which was somewhat different from related studies at the genomic level.