Deciphering effects of humic acid in landfill leachate on the simultaneous nitrification, anammox and denitrification (SNAD) system from performance, electron transfer and microbial community
Deciphering effects of humic acid in landfill leachate on the simultaneous nitrification, anammox and denitrification (SNAD) system from performance, electron transfer and microbial community
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从性能、电子传递和微生物群落解读垃圾渗滤液中腐植酸对同步硝化、厌氧氨氧化和反硝化（SNAD）系统的影响
DOI：
10.1016/j.scitotenv.2021.151178
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发表时间：
2022
影响因子：
9.8
通讯作者：
Jianbo Guo
中科院分区：
文献类型：
--
作者：
Yinuo Liu;Yi Han;Jianbing Zhang;Yanan Hou;Yuanyuan Song;Caicai Lu;Haibo Li;Jianbo Guo
同步硝化-厌氧氨氧化-反硝化（SNAD）系统是处理垃圾渗滤液的有效方法。然而，腐殖酸（HA）作为垃圾渗滤液中的有机污染物和电子穿梭体，其对SNAD系统的影响尚不清楚。本研究表明，HA对厌氧氨氧化菌的抑制作用使NH_4 ~+-N的去除率从100%下降到90.89%，但在SNAD系统中适应后，HA的抑制作用被解除。因此，从性能、电子传递和微生物群落三个方面建立了SNAD体系中HA抑制剂的释放机理。首先，在SNAD系统中，HA可以通过吸附-生物降解过程被有效去除，避免了HA积累导致的性能恶化。电化学分析表明，HA刺激核黄素和黄素单肽（FMN）的分泌，以提高电子传递效率。随着电子传递效率的提高，ETSA和ATP值显著增加，表明HA增强了SNAD系统的微生物代谢活性。进一步的酶活性分析表明，HAO（39.68至69.53 U/L），AMO（242.94至308.36 U/L），HZO（133.73 - 169.65 U/mL），NXR（24.63至54.52 U/L），NAR（94.40至114.36 U/L）和NIR（104.40 ~ 123.74 U/L）活性随HA浓度从0 ~ 200 mg/L增加而提高，表明HA增强了SNAD系统的氮代谢。此外，通过功能菌代谢分工的合理化和异养菌的富集，实现了HA和氮的高效同步去除。总的来说，高效的HA生物降解，更快的电子传递效率和更好的微生物群落代谢分工释放HA抑制，使SNAD系统更能抵抗HA胁迫。本研究揭示了HA对SNAD系统的影响，为SNAD系统处理垃圾渗滤液提供了新的思路。
Simultaneous nitrification, anammox and denitrification (SNAD) system is effective for landfill leachate treatment. However, humic acid (HA) as both an organic pollutant and electron shuttle in landfill leachate, its effects on the SNAD system remain unknown. This study demonstrated that HA initially inhibited NH4+-N removal efficiency due to HA inhibition on anammox bacteria (the lowest fell to 90.89% from 100%), but the HA inhibition was released after adaption in the SNAD system. Hence, the mechanism of releasing HA inhibition in the SNAD system was established from performance, electron transfer and microbial community. Firstly, HA could be effectively removed by an adsorption-biodegradation process in the SNAD system, which avoided deteriorated performance caused by HA accumulation. Electrochemical analysis demonstrated that HA stimulated riboflavin and flavin mononucleotide (FMN) secretion to promote electron transfer efficiency. With the improved electron transfer efficiency, ETSA and ATP values significantly increased, indicating that HA enhanced the microbial metabolism activity of the SNAD system. Further analysis by enzymatic activity assay showed that the HAO (39.68 to 69.53 U/L), AMO (242.94 to 308.36 U/L), HZO (133.73 to 169.65 U/mL), NXR (24.63 to 54.52 U/L), NAR (94.40 to 114.36 U/L) and NIR (104.40 to 123.74 U/L) activities were improved with the HA increased from 0 to 200 mg/L, manifesting that HA enhanced nitrogen metabolism in the SNAD system. Besides, more reasonable metabolic division of labor in functional bacterial and enrichment of heterotrophic bacteria achieved efficient simultaneous removal of HA and nitrogen. Overall, efficient HA biodegradation, faster electron transfer efficiency and better metabolic division of microbial communities released HA inhibition, making the SNAD system more resistant to HA stress. This study shed light on the effects of HA on the SNAD system and provided a new insight for the SNAD system to landfill leachate treatment.