猪粪原料沼气工程系统中的原核微生物群落结构

摘要

采集了中国不同地区的13个猪粪原料沼气工程系统的沼液，利用16S rRNA基因扩增子高通量测序技术研究了原核微生物群落组成及多样性。结果表明，Firmicutes 是猪粪原料沼气工程系统中的主导微生物，其次为Bacteroidetes、Proteobacteria和Chloroflexi。在相似的温度条件下，铵态氮与磷酸盐的比例是影响猪粪原料沼气工程系统原核微生物群落结构及多样性的主要因素。较高的铵磷比会富集Firmicutes门的菌群，尤其是Clostridium sensu stricto属；而较低的铵磷比则有利于Bacteroidetes和Proteobacteria。不同营养类型产甲烷菌对高浓度铵态氮耐受程度不同（氢营养型产甲烷菌>Methanosarcina >Methanosaeta），影响着产甲烷菌群落组成。产甲烷菌和互营菌的群落组成是影响沼气发酵产气效率的重要生物因素，高比例的氢型产甲烷菌和丙酸互营菌更有利于提高产甲烷效率。%Slurry samples from 13 industrial biogas plants using swine manure as raw substrate were collected from different regions in China. The prokaryotic community compositions were investigated using 16S rRNA amplicon high-throughput sequencing technique. The results showed that Firmicutes was the most abundant phylum in these biogas plants, followed by Bacteroidetes, Proteobacteria and Chloroflexi. The ratio of ammonium to phosphate was the main factor affecting prokaryotic community structure and diversity for similar temperatures and substrates. A high ratio of ammonium to phosphate enriched Firmicutes, especially the genusClostridium sensu stricto, while Bacteroidetes and Proteobacteria preferred a low ratio. Ammonium influenced the compositions of methanogens since their tolerance degrees to ammonium were different (hydrogenotrophic methanoges >Methanosarcina >Methanosaeta). Community compositions of methanogens and syntrophs were the most important biotic factors affecting biogas production rate. Biogas production rate could be increased by increasing the abundances of hydrogenotrophic methanoges and syntrophic propionate-oxidizing bacteria.