Granular activated carbon (GAC)-driven microbial electron shuttle boosts denitrification and mitigates N₂O in cold and carbon-limited biofilm system.

IF 12.7 1区生物学 Q1 MICROBIOLOGY

Microbiome Pub Date : 2025-08-01 DOI:10.1186/s40168-025-02161-3

Xiangyu Yang, Mingchen Yao, Peng Li, Jan Peter van der Hoek, Lujing Zhang, Gang Liu

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引用次数: 0

Abstract

Background: Denitrification in wastewater treatment is severely limited under low-temperature and low-carbon ("dual-low") conditions, hindering sustainable nitrogen removal. Biofilm systems, though energy-efficient, suffer from reduced efficiency in such environments due to impaired interspecies electron transfer (IET). Granular activated carbon (GAC), a conductive mediator, offers potential to enhance IET between electroactive microorganisms (EAMs) and denitrifiers, yet its role in dual-low systems remains underexplored. This study investigates GAC's capacity to optimize biofilm functionality and mitigate greenhouse gas (GHG) emissions under these constraints.

Results: Under dual-low conditions (4-6°C, C/N = 4), GAC increased denitrification efficiency by 19.4-21.9% and reduced N₂O emissions by 10.6-22.9%. Metatranscriptomes revealed upregulation of denitrifying genes (e.g., nosZ) and electron transport pathways (e.g., omcB in Geobacter). FISH/SEM confirmed GAC-driven coacervates of EAMs and denitrifiers, linked by nanowires, enhancing direct electron transfer. Microbial diversity decreased, but functional redundancy improved, with Pseudomonas fluorescens and Geobacter sulfurreducens dominating. TOC removal rose under low temperatures, indicating enhanced carbon utilization.

Conclusions: GAC fosters synergistic EAM-denitrifier partnerships, enabling efficient denitrification and GHG mitigation in cold and carbon-limited ("dual-low") biofilm systems, advancing sustainable wastewater management. Video Abstract.

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颗粒活性炭（GAC）驱动的微生物电子穿梭促进低温和碳限制生物膜系统的反硝化和减少N2O。

背景：污水处理中的反硝化在低温和低碳（“双低”）条件下受到严重限制，阻碍了可持续的脱氮。生物膜系统虽然节能，但由于物种间电子转移（IET）受损，在这种环境下效率降低。颗粒活性炭（GAC）是一种导电介质，有可能增强电活性微生物（EAMs）和反硝化菌之间的IET，但其在双低温系统中的作用仍未得到充分研究。本研究探讨了在这些限制条件下GAC优化生物膜功能和减少温室气体排放的能力。结果：双低温条件下（4 ~ 6℃，C/N = 4）， GAC的脱硝效率提高19.4 ~ 21.9%，N2O排放量减少10.6 ~ 22.9%。亚转录组显示反硝化基因（如nosZ）和电子传递途径（如Geobacter中的omcB）上调。FISH/SEM证实了gac驱动的eam和反硝化剂凝聚体，通过纳米线连接，增强了直接电子转移。微生物多样性下降，但功能冗余得到改善，荧光假单胞菌和硫还原地杆菌占主导地位。低温下TOC去除率上升，表明碳利用率提高。结论：GAC促进协同eam -反硝化剂伙伴关系，在低温和碳限制（“双低”）生物膜系统中实现高效反硝化和温室气体减排，促进可持续废水管理。视频摘要。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Microbiome MICROBIOLOGY-

CiteScore

21.90

自引率

2.60%

发文量

198

审稿时长

4 weeks

期刊介绍： Microbiome is a journal that focuses on studies of microbiomes in humans, animals, plants, and the environment. It covers both natural and manipulated microbiomes, such as those in agriculture. The journal is interested in research that uses meta-omics approaches or novel bioinformatics tools and emphasizes the community/host interaction and structure-function relationship within the microbiome. Studies that go beyond descriptive omics surveys and include experimental or theoretical approaches will be considered for publication. The journal also encourages research that establishes cause and effect relationships and supports proposed microbiome functions. However, studies of individual microbial isolates/species without exploring their impact on the host or the complex microbiome structures and functions will not be considered for publication. Microbiome is indexed in BIOSIS, Current Contents, DOAJ, Embase, MEDLINE, PubMed, PubMed Central, and Science Citations Index Expanded.