Zhang Yanru, Xiang Yinping, Yang Zhaohui, Xu Rui
Fujian Key Laboratory of Pollution Control & Resource Reuse, College of Environmental and Resource Sciences, Fujian Normal University, Fuzhou, 350007, People's Republic of China.
College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China.
Environ Sci Pollut Res Int. 2024 May;31(25):36716-36727. doi: 10.1007/s11356-024-33699-8. Epub 2024 May 16.
Thermophilic anaerobic digestion (TAD) represents a promising biotechnology for both methane energy production and waste stream treatment. However, numerous critical microorganisms and their metabolic characteristics involved in this process remain unidentified due to the limitations of culturable isolates. This study investigated the phylogenetic composition and potential metabolic traits of bacteria and methanogenic archaea in a TAD system using culture-independent metagenomics. Predominant microorganisms identified in the stable phase of TAD included hydrogenotrophic methanogens (Methanothermobacter and Methanosarcina) and hydrogen-producing bacteria (Coprothermobacter, Acetomicrobium, and Defluviitoga). Nine major metagenome-assembled genomes (MAGs) associated with the dominant genera were selected to infer their metabolic potentials. Genes related to thermal resistance were widely found in all nine major MAGs, such as the molecular chaperone genes, Clp protease gene, and RNA polymerase genes, which may contribute to their predominance under thermophilic condition. Thermophilic temperatures may increase the hydrogen partial pressure of Coprothermobacter, Acetomicrobium, and Defluviitoga, subsequently altering the primary methanogenesis pathway from acetoclastic pathway to hydrogenotrophic pathway in the TAD. Consequently, genes encoding the hydrogenotrophic methanogenesis pathway were the most abundant in the recovered archaeal MAGs. The potential interaction between hydrogen-producing bacteria and hydrogenotrophic methanogens may play critical roles in TAD processes.
嗜热厌氧消化（TAD）是一种在甲烷能源生产和废物流处理方面都颇具前景的生物技术。然而，由于可培养分离物的局限性，参与该过程的众多关键微生物及其代谢特征仍未明确。本研究使用不依赖培养的宏基因组学方法，调查了TAD系统中细菌和产甲烷古菌的系统发育组成及潜在代谢特征。在TAD稳定阶段鉴定出的主要微生物包括嗜氢产甲烷菌（嗜热栖热甲烷杆菌属和甲烷八叠球菌属）和产氢细菌（嗜热栖热杆菌属、乙酸微菌属和脱卤单胞菌属）。选择了与优势属相关的9个主要宏基因组组装基因组（MAG）来推断它们的代谢潜力。在所有9个主要MAG中广泛发现了与耐热性相关的基因，如分子伴侣基因、Clp蛋白酶基因和RNA聚合酶基因，这可能有助于它们在嗜热条件下占优势。嗜热温度可能会增加嗜热栖热杆菌属、乙酸微菌属和脱卤单胞菌属的氢分压，随后将TAD中的主要产甲烷途径从乙酸裂解途径改变为嗜氢途径。因此，编码嗜氢产甲烷途径的基因在回收的古菌MAG中最为丰富。产氢细菌和嗜氢产甲烷菌之间的潜在相互作用可能在TAD过程中起关键作用。
