In this study, the effect of modulating fulvic acid (FA) concentrations (0, 25 and 50 mg/L) on nitrogen removal in a bioelectrochemical hydrogen autotrophic denitrification system (BHDS) was investigated. Results showed that FA increased the nitrate (NO3–-N) removal rate of the BHDSs from 37.8 to 46.2 and 45.2 mg N/(L·d) with a current intensity of 40 mA. The metagenomic analysis revealed that R2 (25 mg/L) was predominantly populated by autotrophic denitrifying microorganisms, which enhanced denitrification performance by facilitating electron transfer. Conversely, R3 (50 mg/L) exhibited an increase in genes related to the heterotrophic process, which improved the denitrification performance through the collaborative action of both autotrophic and heterotrophic denitrification pathways. Besides, the study also identified a potential for nitrogen removal in Serpentinimonas, which have been rarely studied. The interesting set of findings provide valuable reference for optimizing BHDS for nitrogen removal and promoting specific denitrifying genera within the system.

中文翻译：

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探讨黄腐酸对电化学氢驱动自养反硝化系统的影响：性能、微生物特性和机制


在本研究中，研究了调节黄腐酸（FA）浓度（0、25和50 mg/L）对生物电化学氢自养反硝化系统（BHDS）中脱氮的影响。结果表明，电流强度为 40 mA 时，FA 将 BHDS 的硝酸盐 (NO3–-N) 去除率从 37.8 提高到 46.2 和 45.2 mg N/(L·d)。宏基因组分析表明，R2（25 mg/L）主要由自养反硝化微生物组成，它们通过促进电子转移来增强反硝化性能。相反，R3（50 mg/L）表现出与异养过程相关的基因的增加，通过自养和异养反硝化途径的协同作用提高了反硝化性能。此外，该研究还发现了蛇形单胞菌的脱氮潜力，而这方面的研究很少。这组有趣的发现为优化 BHDS 脱氮和促进系统内特定的反硝化属提供了有价值的参考。