基质负荷对秸秆与污泥厌氧消化微生物群落结构的影响

为明确秸秆污泥厌氧消化体系中微生物群落的结构特征,采用Ⅰllumina HiSeq高通量测序技术,研究在高低两种基质负荷条件下微生物群落结构的变化和多样性,并监测其产气性能.结果表明:高负荷基质条件下（TS 20 g/(L·d)）,平均日产气量为4.1 L；低负荷基质条件下（TS 12 g/(L·d)）,平均日产气量为2.1 L.高负荷基质条件下细菌的相对丰度为91.57%,产甲烷古菌的相对丰度为8.43%；低负荷基质条件下细菌的相对丰度为94.35%,产甲烷古菌的相对丰度为5.65%,高负荷基质条件下产甲烷古菌的丰度比在低负荷基质条件下相对增加了49.2%,表明产甲烷古菌的相对丰度和产气量有一定的正相关性.高负荷基质条件下的前3种优势菌群分别为:相对丰度为51.06%的拟杆菌门（Bacteroidetes）、11.65%的厚壁菌门（Firmicutes）、8.25%的广古菌门（Euryarchaeota）.低负荷条件下的前3种优势菌群分别为:相对丰度为50.78%的拟杆菌门（Bacteroidetes）,7.67%的Cloacimonetes、6.46%的互养菌门（Synergistetes）.两种基质条件下都检测到12种产甲烷菌属,分属氢营养型、甲基营养型、乙酸营养型,说明整个秸秆污泥厌氧消化体系的代谢途径较为丰富,各种微生物群落生长代谢相互依存、相互平衡,具有一定的抗冲击负荷,建立了较为平衡的稳态缓冲体系.

Effect of substrate load on microbial community of anaerobic digestion in straw and sludge

To investigate the structural characteristics of microbial community in the anaerobic digestion system of straw and sludge, the Illumina HiSeq high-throughput sequencing technology was used to study the changes and diversity of microbial community structure under high and low substrate loading conditions, and monitor its gas production. Results show that the average daily gas production was about 4.1 L under high load conditions (20 g/(L·d)) and about 2.1 L under low load conditions (12 g/(L·d)). The relative abundance of bacteria under high load substrate conditions was 91.57%, and the relative abundance of methanogenic archaea was 8.43%; the relative abundance of bacteria under low load substrate conditions was 94.35%, and the relative abundance of methanogenic archaea was 5.65%. The relative abundance of methanogenic archaea under high load substrate conditions increased about 49.2% compared with that under low load substrate conditions, indicating that there was a positive correlation between the relative abundance of archaea and gas production. The first three dominant phyla under high load conditions were Bacteroidetes with a relative abundance of 51.06%, Firmicutes with that of 11.65%, and Euryarchaeota with that of 8.25%. The first three dominant phyla under low load conditions were Bacteroidetes with a relative abundance of 50.78%, Cloacimonetes with that of 7.67%, and Synergistetes with that of 6.46%. Twelve kinds of methanogens archaea were detected under the two substrate conditions, which belong to hydrogenotrophic, methylotrophic, and aciticlasitic, indicating that the metabolic pathway of the whole straw and sludge anaerobic digestion system was rich, the growth metabolism of various microbial communities was interdependent and balanced with certain anti-shock loading, and a relatively balanced buffer system was established.