Department of Bioscience, Federal University of Paraná, Sector Palotina, R. Pioneiro, 215, Jardim Dallas, Palotina, PR, 85900-000, Brazil.
Department of Biochemistry and Molecular Biology, Federal University of Paraná, Av. Coronel Francisco H. dos Santos,100, CP 19031, Centro Politécnico, Curitiba, PR, 81531-980, Brazil.
Sci Total Environ. 2020 Nov 10;742:140314. doi: 10.1016/j.scitotenv.2020.140314. Epub 2020 Jun 23.
Anaerobic digestion can produce biogas as an eco-friendly energy source, driven by a microbial community-dependent process and, as such, suffer influences from many biotic and abiotic factors. Understanding the players and how they interact, the mechanisms involved, what the factors are, and how they influence the biogas process and production is an important way to better control it and make it more efficient. Metagenomic approach is a powerful tool to assess microbial diversity and further, allow correlating changes in microbial communities with multiple factors in virtually all environments. In the present study, we used metagenomic approach to assess microbial community structure changes in two biodigesters, differing in their biogas production capacity, architecture, and feed. A total of 1,440,096 reads of the 16S rRNA gene V4 region were obtained and analyzed. The main bacterial phyla were Firmicutes and Bacteroidetes in both biodigesters, but the biodiversity was greater in the Upflow Anaerobic Sludge Blanket (UASB) reactor fed with bovine manure than in the Continuous Stirred Tank Reactor (CSTR) fed with swine manure, which also correlated with an increase in biogas or methane production. Microbial community structure associated with biodigesters changed seasonally and depended on animal growth stage. Random forest algorithm analysis revealed key microbial taxa for each biodigester. Candidatus Cloacomonas, Methanospirillum, and Methanosphaera were the marker taxa for UASB and the archaea groups Methanobrevibacter and Candidatus Methanoplasma were the marker taxa for CSTR. A high abundance of Candidatus Methanoplasma and Marinimicrobia SAR406 clade suggested lower increments in methane production. Network analysis pointed to negative and positive associations and specific key groups, essential in maintaining the anaerobic digestion (AD) process, as being uncultured Parcubacteria bacteria, Candidatus Cloacomonas, and Candidatus Methanoplasma groups, whose functions in AD require investigation.
厌氧消化可以产生沼气作为一种环保能源，由微生物群落依赖的过程驱动，因此会受到许多生物和非生物因素的影响。了解参与者及其相互作用方式、涉及的机制、因素是什么以及它们如何影响沼气过程和生产，是更好地控制沼气生产并提高其效率的重要途径。宏基因组学方法是评估微生物多样性的有力工具，并且可以进一步将微生物群落的变化与几乎所有环境中的多种因素相关联。在本研究中，我们使用宏基因组学方法来评估两个生物消化器中微生物群落结构的变化，这两个生物消化器在沼气产生能力、结构和进料方面存在差异。共获得和分析了 16S rRNA 基因 V4 区的 1440096 个读数。两个生物消化器中的主要细菌门是厚壁菌门和拟杆菌门，但在牛粪喂养的上流式厌氧污泥床（UASB）反应器中的生物多样性大于猪粪喂养的连续搅拌罐反应器（CSTR），这也与沼气或甲烷产量的增加有关。与生物消化器相关的微生物群落结构随季节变化，并取决于动物生长阶段。随机森林算法分析揭示了每个生物消化器的关键微生物类群。Candidatus Cloacomonas、Methanospirillum 和 Methanosphaera 是 UASB 的标记类群，而古菌组 Methanobrevibacter 和 Candidatus Methanoplasma 是 CSTR 的标记类群。Candidatus Methanoplasma 和 Marinimicrobia SAR406 分支的高丰度表明甲烷产量的增加较低。网络分析指出了负面和正面的关联以及特定的关键群体，这些群体对于维持厌氧消化（AD）过程至关重要，例如未培养的 Parcubacteria 细菌、Candidatus Cloacomonas 和 Candidatus Methanoplasma 群体，它们在 AD 中的功能需要进一步研究。
