Kwon Hyejeong, Li Bo, Xu Min, Wang Qingshi, Maqbool Tahir, Lu Huijie, Winkler Mari, Jiang Daqian
Civil, Construction, and Environmental Engineering, The University of Alabama, Tuscaloosa, AL, USA.
Civil and Environmental Engineering, University of Washington, Seattle, WA, USA.
J Hazard Mater. 2025 Jul 15;492:138110. doi: 10.1016/j.jhazmat.2025.138110. Epub 2025 Mar 31.
Autotrophic bioelectrochemical denitrification (BED) holds promise for nitrate remediation. However, the accumulation of byproducts such as NO, NO, and NH, poses a significant challenge to effluent quality and climate adaptation. This study hypothesized that introducing anaerobic ammonium oxidation bacteria (anammox) to BED could alleviate this issue through synergy: a) anammox can utilize NH and NO from BED without producing NO, as seen in canonical denitrification, and b) BED can recycle NO from the anammox anabolic pathway. Results showed that Anammox_BED reduced NO accumulation by two-thirds, lowered the relative abundance of NO by 80 %, and eliminated NO. Metagenomic analysis revealed that the anammox species Ca. Brocadia sapporoensis tripled in abundance in the bulk sludge. Meanwhile, Pseudomonas stutzeri and Bosea robiniae, species capable of reducing nitrate via extracellular electron transfer (EET) and supplying NO to anammox, halved in relative abundance, while the abundance of Stenotrophomonas acidaminiphila, a non-EET, ammonia assimilation species, doubled following anammox introduction. Metatranscriptomic analysis found upregulation of denitrification-related functional genes in Anammox_BED biofilm and survival- and motility- related genes in bulk sludge, possibly due to insufficient substrate. Overall, BED-Anammox successfully diverted the rate-limiting EET nitrite reduction towards anammox-driven nitrite utilization thereby mitigating the generation of unwanted intermediates.
自养生物电化学反硝化（BED）在硝酸盐修复方面具有潜力。然而，诸如NO、NO和NH等副产物的积累对出水水质和气候适应性构成了重大挑战。本研究假设，将厌氧氨氧化细菌（anammox）引入BED可以通过协同作用缓解这一问题：a）厌氧氨氧化可以利用BED中的NH和NO，而不会像传统反硝化那样产生NO；b）BED可以回收厌氧氨氧化合成代谢途径中的NO。结果表明，厌氧氨氧化-BED使NO积累减少了三分之二，使NO的相对丰度降低了80%，并消除了NO。宏基因组分析表明，厌氧氨氧化菌Ca. Brocadia sapporoensis在活性污泥中的丰度增加了两倍。同时，能够通过细胞外电子转移（EET）还原硝酸盐并为厌氧氨氧化提供NO的斯氏假单胞菌和罗氏博斯氏菌的相对丰度减半，而在引入厌氧氨氧化后，非EET氨同化菌嗜氨基寡养单胞菌的丰度增加了一倍。宏转录组分析发现，厌氧氨氧化-BED生物膜中反硝化相关功能基因上调，活性污泥中生存和运动相关基因上调，这可能是由于底物不足所致。总体而言，BED-厌氧氨氧化成功地将限速的EET亚硝酸盐还原转向厌氧氨氧化驱动的亚硝酸盐利用，从而减少了不需要的中间产物的产生。
