The acceleration of nitrate removal in wastewater treatment by redox mediator (RM) is greatly weakened due to wash-out loss and mass transfer resistance (low hydrophilia) of RM during operation. In this study, an RM reactor with the fixed 1-Amino-4-hydroxyanthraquinone (AHAQ) and three core strains was established and achieved high nitrate removal efficiency (NRE) under low carbon to nitrogen ratio (C/N) and short hydraulic retention time (HRT) conditions, with the maximum efficiency of 99.41% (14.00 mg L⁻¹ h⁻¹) and average improvement by 11.97% (1.41 mg L⁻¹ h⁻¹). This acceleration led to more proportion of carbon consumption by denitrifying bacteria and improved their competitiveness against others in carbon deficiency, although resulting in nitrite accumulation (NIA) in lower C/N. The RM reactor induced the decorrelation tendencies between NRE and active extracellular organics and more sensitive denitrification toward C/N, which favored the stability of effluent organics and biological activities. The increase of oxidative phosphorylation and ubiquinone and other terpenoid-quinone biosynthesis pathway suggested electron transport activity was potentially enhanced by AHAQ. Although the lower C/N deteriorated the reactor NRE, the abundances of amino acids-, fatty acids- and carbohydrate-related metabolisms (45% of the total up-regulating pathways) were enhanced to utilize carbon source effectively. Meanwhile, the enhanced phosphotransferase system facilitated the balance between carbon and nitrogen metabolism. These indicated the changes in biological strategy to grow better and resist the adverse condition. This study highlighted the superior NRE by AHAQ in an immobilized reactor with core strains and more importantly, extended the RM application in wastewater treatment.

由于氧化还原介体（RM）在运行过程中的冲洗损失和传质阻力（低亲水性），氧化还原介体（RM）对废水处理中硝酸盐去除的加速被大大削弱。在本研究中，建立了固定 1-氨基-4-羟基蒽醌 (AHAQ) 和三个核心菌株的 RM 反应器，并在低碳氮比 (C/N) 和短水力保留下实现了高硝酸盐去除效率 (NRE)时间 (HRT) 条件下，最大效率为 99.41% (14.00 mg L ^-1 h ^-1 )，平均提高 11.97% (1.41 mg L ^-1 h ^-1）。这种加速导致反硝化细菌消耗更多的碳，并提高了它们在碳缺乏时与其他细菌的竞争力，尽管导致亚硝酸盐积累 (NIA) 的 C/N 较低。RM反应器诱导了NRE与活性细胞外有机物之间的去相关趋势以及对C/N更敏感的反硝化作用，这有利于出水有机物的稳定性和生物活性。氧化磷酸化和泛醌和其他萜类-醌生物合成途径的增加表明 AHAQ 可能增强电子传递活性。虽然较低的 C/N 使反应器 NRE 恶化，但氨基酸的丰度——， 脂肪酸——和碳水化合物相关的代谢（占总上调途径的 45%）得到增强，以有效利用碳源。同时，增强的磷酸转移酶系统促进了碳和氮代谢之间的平衡。这些表明生物策略的变化以更好地生长和抵抗不利条件。这项研究突出了 AHAQ 在具有核心菌株的固定反应器中的优越 NRE，更重要的是，扩展了 RM 在废水处理中的应用。