Chen Siyi, Kong Ziang, Qiu Liwei, Wang Han, Yan Qun
School of Environmental and Civil Engineering, Jiangnan University, Wuxi, 214122, China.
Changzhou Cheff Environmental Protection Technology Co., Ltd, Changzhou, 213164, China.
Environ Res. 2025 Jan 1;264(Pt 1):120295. doi: 10.1016/j.envres.2024.120295. Epub 2024 Nov 5.
Anaerobic digestion (AD) is a promising technology for achieving both organic wastes treatment and energy recovery. However, challenges such as ammonia inhibition still remain. Quorum sensing (QS) system is relevant with the regulation of microbial community behaviors by releasing and sensing signal molecules, which could improve methane production during AD process. Therefore, the current study explored the effects of different quorum sensing signal molecules on alleviation of ammonia inhibition. The results showed that both secretion of N-butyryl--homoserine lactone (C4-HSL) and N-(β-ketocaproyl)--homoserine lactone (3OC6-HSL) could be inhibited by high ammonia stress while stimulation of N-hexanoyl--homoserine lactone (C6-HSL) and N-octanoyl--homoserine lactone (C8-HSL) secretion might be triggered by ammonia toxicity. Moreover, the alleviation of ammonia inhibition could be achieved by both introducing 3OC6-HSL (0.5 μM) and combination of 3OC6-HSL (0.1 μM) and biochar (4 g/L). Exogenous 3OC6-HSL could regulate microbial social behaviors and enhance the secretion of extracellular polymeric substances (EPS) to promote anaerobic digestion. In addition, the mitigation of ammonia inhibition through exogenous 3OC6-HSL and biochar were confirmed by microbial community changes (Methanobacterium, Propionicicella and Petrimonas). Critical enzymes involved in both acidification and methanogenic steps were enhanced after adding the combination of 3OC6-HSL and biochar. The combination of low levels of 3OC6-HSL and biochar could promote both direct interspecies electron transfer (DIET) process and communication between different anaerobic microorganisms to mitigate ammonia inhibition. The current study will provide primary insights for conquering ammonia inhibition during biomethanation.
厌氧消化（AD）是一种实现有机废物处理和能源回收的很有前景的技术。然而，诸如氨抑制等挑战仍然存在。群体感应（QS）系统与通过释放和感知信号分子来调节微生物群落行为有关，这可以提高厌氧消化过程中的甲烷产量。因此，当前的研究探讨了不同群体感应信号分子对缓解氨抑制的影响。结果表明，高氨胁迫会抑制N-丁酰基-L-高丝氨酸内酯（C4-HSL）和N-（β-酮己酰基）-L-高丝氨酸内酯（3OC6-HSL）的分泌，而氨毒性可能会触发N-己酰基-L-高丝氨酸内酯（C6-HSL）和N-辛酰基-L-高丝氨酸内酯（C8-HSL）分泌的刺激。此外，引入3OC6-HSL（0.5 μM）以及3OC6-HSL（0.1 μM）和生物炭（4 g/L）的组合都可以实现氨抑制的缓解。外源性3OC6-HSL可以调节微生物的社会行为并增强细胞外聚合物（EPS）的分泌，以促进厌氧消化。此外，通过微生物群落变化（甲烷杆菌属、丙酸杆菌属和石化单胞菌属）证实了外源性3OC6-HSL和生物炭对氨抑制的缓解作用。添加3OC6-HSL和生物炭的组合后，参与酸化和产甲烷步骤的关键酶得到增强。低水平的3OC6-HSL和生物炭的组合可以促进直接种间电子转移（DIET）过程以及不同厌氧微生物之间的交流，以减轻氨抑制。当前的研究将为克服生物甲烷化过程中的氨抑制提供初步见解。
