Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States.
Environ Sci Technol. 2022 May 17;56(10):6689-6698. doi: 10.1021/acs.est.2c01029. Epub 2022 May 5.
Immigration has been recently recognized as an important ecological process that affects the microbial community structure in diverse ecosystems. However, the fate of microbial immigrants in the new environment and their involvement in the local biochemical network remain unclear. In this study, we performed meta-omics-supervised characterization of immigrants' activities in anaerobic sludge digesters. Metagenomic analyses revealed that immigrants from the feed sludge accounted for the majority of populations capable of anaerobic respiration in a digester. Electron acceptors that were predicted to be respired, including nitrate, nitrite, sulfate, and elemental sulfur, were added to digester sludge in batch tests. Consumption of up to 91% of the added electron acceptors was observed within the experiment period. 16S rRNA sequencing detected populations that were stimulated by the electron acceptors, largely overlapping with respiration-capable immigrants identified by metagenomic analysis. Metatranscriptomic analysis of the batch tests provided additional evidence for upregulated expression of respiration genes and concomitant suppressed expression of methanogenesis. Anaerobic respiration activity was further evaluated in full-scale digesters in nine wastewater treatment plants. Although nitrate and sulfate respiration were ubiquitous, the expression level of respiration genes was generally 2-3 orders of magnitude lower than the expression of methanogenesis in most digesters, suggesting marginal ecological roles by immigrants in full-scale digester ecosystems.
移民最近被认为是一种重要的生态过程，它影响着不同生态系统中的微生物群落结构。然而，微生物移民在新环境中的命运及其在当地生化网络中的参与程度仍不清楚。在这项研究中，我们对厌氧污泥消化器中的移民活动进行了元组学监督特征描述。宏基因组分析显示，来自进料污泥的移民占消化器中能够进行厌氧呼吸的大多数种群。在批处理试验中，向消化器污泥中添加了预测可被呼吸的电子受体，包括硝酸盐、亚硝酸盐、硫酸盐和元素硫。在实验期间观察到高达 91%的添加电子受体被消耗。16S rRNA 测序检测到受电子受体刺激的种群，这些种群与通过宏基因组分析确定的具有呼吸能力的移民大部分重叠。批处理试验的代谢组学分析为呼吸基因的上调表达和伴随的甲烷生成的抑制表达提供了额外的证据。在九个污水处理厂的全规模消化器中进一步评估了厌氧呼吸活性。虽然硝酸盐和硫酸盐呼吸普遍存在，但在大多数消化器中，呼吸基因的表达水平通常比甲烷生成的表达水平低 2-3 个数量级，这表明移民在全规模消化器生态系统中的生态作用微不足道。
