Department of Chemical Engineering, Institute of Technology, Universidade de Santiago de Compostela, Constantino Candeira s/n, 15782 Santiago de Compostela, Galicia, Spain.
Department of Chemical Engineering and Environmental Technology, School of Industrial Engineerings, Venue Dr. Mergelina, C/ Dr. Mergelina, s/n, Valladolid 47011, Spain; Department of Chemical Engineering, Institute of Technology, Universidade de Santiago de Compostela, Constantino Candeira s/n, 15782 Santiago de Compostela, Galicia, Spain.
Chemosphere. 2019 May;222:323-332. doi: 10.1016/j.chemosphere.2019.01.124. Epub 2019 Jan 23.
There is still a lack of information about microbial interactions of anaerobic digestion microbiome during process disturbance which limits our ability to predict the mechanisms that drive community dynamics on these events. This paper aims to determine how an organic overloading affects these interactions and to characterize in detail the microbiome structure and diversity in sewage sludge anaerobic reactors during an acidosis event. Two identical sewage sludge anaerobic reactors were subjected to an organic loading shock by adding glycerol waste. As consequence, volatile fatty acids accumulated after only 24 h (up to 2.5 g/L) while Bacteroidales and Methanomicrobiales became displaced by Firmicutes and Methanosaeta sp, showing that reactor acidosis can occur without an immediate decline of this methanogen. Network analysis revealed 9 clusters of co-occurring microorganisms with different behaviors during overloading. At first, Veillonellaceae family, the main glycerol degrading, associated with Candidatus Cloacimonetes, volatile fatty acids fermenters, increased their relative abundance in detriment of the syntrophic bacteria; although as conditions become more acidic, these groups were displaced by other fermenters like Porphyromonadaceae and Chitinophagaceae. Eventually, the methanogenesis failed 72 h after organic overloading, when pH reached values lower than 6. Overall, our results showed a succession of functionally redundant microorganisms, most likely because of niche specialization during organic overloading. The detailed temporal analysis elucidated the processes governing the dynamics anaerobic digestion microbiome, a knowledge required to develop anaerobic digestion management strategies based on its microbiome during process disturbances.
在过程干扰期间，关于厌氧消化微生物组的微生物相互作用仍然缺乏信息，这限制了我们预测驱动这些事件中群落动态的机制的能力。本文旨在确定有机负荷增加如何影响这些相互作用，并详细表征在酸中毒事件期间污水污泥厌氧反应器中的微生物组结构和多样性。通过添加甘油废物，两个相同的污水污泥厌氧反应器受到有机负荷冲击。结果，挥发性脂肪酸在 24 小时后仅积累（高达 2.5 g/L），而拟杆菌门和甲烷微菌门被厚壁菌门和产甲烷菌取代，表明反应器酸中毒可能不会导致产甲烷菌立即下降。网络分析显示，在过载期间，有 9 个具有不同行为的微生物共生簇。首先，与发酵挥发性脂肪酸的 Candidatus Cloacimonetes 相关的主要甘油降解菌韦荣氏球菌科增加了相对丰度，损害了共生细菌；尽管随着条件变得更加酸性，这些群体被其他发酵菌如卟啉单胞菌科和几丁质噬菌科取代。最终，在有机负荷增加 72 小时后，当 pH 值降至 6 以下时，甲烷生成失败。总体而言，我们的结果显示了功能冗余微生物的连续出现，这很可能是由于有机负荷增加期间的生态位特化。详细的时间分析阐明了厌氧消化微生物组动力学的过程，这是在过程干扰期间基于其微生物组开发厌氧消化管理策略所需的知识。
