There have been extensive applications of waste activated sludge (WAS) in anaerobic co-digestion (AcoD). Nonetheless, mechanisms through which AcoD systems maintain stability, particularly under nutrient-stressed conditions, are under-appreciated. In this study, the role of WAS in a nutrient-stressed WAS-food waste AcoD system was re-evaluated. Our findings demonstrated that WAS-based co-digestion increased methane production (by 20–60%) as WAS bolsters such systems’ resilience via establishing a core niche-based microbial balance. The carbon utilization investigation suggested a microbial niche balance is attainable if two conditions are satisfied: 1) hydrolysis efficiency is greater than 50%; and 2) both the acidogenesis-to-hydrolysis and acetogenesis-to-hydrolysis efficiencies surpass 0.5. Metagenomic assembly genome (MAG) analysis indicated that the versatile metabolic characteristics strengthened the microbial niche balance, rendering the system resilient and efficient through a syntrophic mode, contributing to both acidogenesis and acetogenesis. The findings of this study provide new insights into the ecological effects of WAS on AcoD.

中文翻译：

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关于废活性污泥在营养胁迫共消化中的生态作用的新见解


废弃活性污泥（WAS）在厌氧共消化（AcoD）中得到了广泛的应用。尽管如此，AcoD 系统维持稳定性的机制，特别是在营养紧张的条件下，仍未被充分认识。在本研究中，重新评估了 WAS 在营养胁迫的 WAS-食物垃圾 AcoD 系统中的作用。我们的研究结果表明，基于 WAS 的共消化增加了甲烷产量（增加了 20-60%），因为 WAS 通过建立基于核心生态位的微生物平衡来增强此类系统的弹性。碳利用研究表明，如果满足两个条件，就可以实现微生物生态位平衡：1）水解效率大于50％； 2)产酸-水解效率和产醋-水解效率均超过0.5。宏基因组组装基因组（MAG）分析表明，多功能代谢特征加强了微生物生态位平衡，通过互养模式使系统具有弹性和效率，有助于酸生成和乙酸生成。这项研究的结果为 WAS 对 AcoD 的生态影响提供了新的见解。