Various pretreatments are commonly adopted to facilitate dissolved organic matter (DOM) release from waste activated sludge (WAS) for high-valued volatile fatty acids (VFAs) promotion, while the interplay impact of DOM dynamics transformation on microbial population and metabolic function traits is poorly understood. This work constructed “DOM-microorganisms-metabolism-VFAs” symbiotic ecologic networks to disclose how DOM dynamics variation intricately interacts with bacterial community networks, assembly processes, and microbial traits during WAS fermentation. The distribution of DOM was altered by different pretreatments, triggering the release of easily biodegradable compounds (O/C ratio > 0.3) and protein-like substance. This alteration greatly improved the substrates biodegradability (higher biological index) and upregulated microbial metabolism capacity (, hydrolysis and fatty acid synthesis). In turn, microbial activity modifications augment substance metabolism level and expedite the conversion of highly reactive compounds (proteins-like DOM) to VFAs, leading to 1.6–4.2 fold rise in VFAs generation. Strong correlations were found between proteins-like DOM and topological properties of DOM-bacteria associations, suggesting that high DOM availability leads to more intricate ecological networks. A change in the way communities assemble, shifting from stronger uniform selection in pH10 and USp reactors to increased randomness in heat reactor, was linked to DOM composition alterations. The ecologic networks further revealed metabolic synergy between hydrolytic-acidogenic bacteria ( and ) and biodegradable DOM ( proteins and amino sugars) leading to higher VFAs generation. This study provides a deeper knowledge of the inherent connections between DOM and microbial traits for efficient VFAs biosynthesis during WAS anaerobic fermentation, offering valuable insights for effective WAS pretreatment strategies.

中文翻译：

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阐明各种预处理引发的污泥厌氧发酵中溶解有机物变化与微生物共生网络的相互作用


通常采用各种预处理来促进废弃活性污泥（WAS）中溶解有机物（DOM）的释放，以促进高价值挥发性脂肪酸（VFA）的产生，但DOM动态转化对微生物种群和代谢功能特性的相互作用影响很差明白了。该工作构建了“DOM-微生物-代谢-VFA”共生生态网络，揭示了WAS发酵过程中DOM动态变化如何与细菌群落网络、组装过程和微生物性状错综复杂地相互作用。不同的预处理改变了DOM的分布，引发易生物降解的化合物（O/C比> 0.3）和蛋白质样物质的释放。这种改变极大地提高了底物的生物降解性（更高的生物指数）并上调了微生物代谢能力（水解和脂肪酸合成）。反过来，微生物活性的改变会提高物质代谢水平，并加速高反应性化合物（DOM 等蛋白质）向 VFA 的转化，导致 VFA 的生成量增加 1.6-4.2 倍。我们发现类蛋白质 DOM 与 DOM-细菌关联的拓扑特性之间存在很强的相关性，这表明高 DOM 可用性会导致更复杂的生态网络。群落聚集方式的变化，从 pH10 和 USp 反应器中更强的均匀选择转变为热反应器中增加的随机性，与 DOM 组成的变化有关。生态网络进一步揭示了水解产酸细菌（和）与可生物降解的 DOM（蛋白质和氨基糖）之间的代谢协同作用，导致更高的 VFA 生成。 这项研究深入了解了 DOM 与微生物性状之间的内在联系，以实现 WAS 厌氧发酵过程中高效 VFA 生物合成，为有效的 WAS 预处理策略提供了宝贵的见解。