Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore.
Institute of Marine Science and Technology, Shandong University, Qingdao, Shandong 266237, China.
Bioresour Technol. 2022 Sep;360:127574. doi: 10.1016/j.biortech.2022.127574. Epub 2022 Jul 2.
The ecological roles of microbial communities and how they interact with each other in thermal hydrolysis process (THP) assisted thermophilic anaerobic digestion (THP-AD) reactors remain largely unknown, especially under propionate stress. Two thermophilic THP-AD reactors had methane yield of 240-248 mL/g VS, but accumulated approximately 2000 mg/L propionate. Genome-centric metagenomics analysis showed that 68 metagenome-assembled genomes (MAGs) were recovered, 32 MAGs of which were substantially enriched. Firmicutes spp. dominated the enriched microbial community, including hydrolytic/fermentative bacteria and syntrophs. Methanogenic activities were mainly mediated by Methanosarcina sp. and Methanothermobacter spp. In addition to hydrogenotrophic methanogens, Thermodesulfovibrio sp. could also be a vital H scavenger, contributing to maintaining low H partial pressure in the bioreactors. The remarkable accumulation of propionate could be likely attributed to the weak syntrophic propionate-oxidizing activity or its absence. These findings advanced our knowledge about the mutualistic symbiosis of carbon metabolism in thermophilic THP-AD reactors.
微生物群落的生态作用及其在热水解工艺（THP）辅助嗜热厌氧消化（THP-AD）反应器中的相互作用方式在很大程度上尚不清楚，特别是在丙酸压力下。两个嗜热 THP-AD 反应器的甲烷产率为 240-248 mL/g VS，但积累了约 2000 mg/L 的丙酸。基于基因组的宏基因组学分析显示，共回收了 68 个宏基因组组装基因组（MAG），其中 32 个 MAG 得到了实质性富集。厚壁菌门 spp. 主导了富集的微生物群落，包括水解/发酵细菌和共栖菌。产甲烷活性主要由 Methanosarcina sp. 和 Methanothermobacter spp. 介导。除了氢营养型产甲烷菌外，Thermodesulfovibrio sp. 也可能是一种重要的 H 清除剂，有助于维持生物反应器中低的 H 分压。丙酸的显著积累可能归因于较弱的丙酸氧化共代谢活性或其缺失。这些发现提高了我们对嗜热 THP-AD 反应器中碳代谢共生关系的认识。
