Deciphering microplastic-driven denitrification in rivers: carbon bioavailability, keystone microbes and electron transfer efficiency

IF 12.8 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2027-01-01 Epub Date: 2026-09-25 DOI:10.1016/j.watres.2026.127022

Cheng Yang, Xingnian Ren, Jianhao Song, Xiangtian Man, Yu Xiang, Ruxin Yang, Peng Zhang, Mengli Chen, Han Zhang

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引用次数: 0

Abstract

Continuous input of microplastics (MPs) into rivers poses an increasingly serious ecological threat. MPs gradually release dissolved organic carbon during aging and degradation. However, the molecular mechanisms by which MP-released carbon drive denitrification in sediments remain unclear. This study combined the data of 251 freshwater plastisphere and microcosm experiment to resolve this issue. We found high denitrifier abundance (66.65% at phylum level) in plastispheres, and microcosm experiments confirmed the utilization of MPs as a carbon source. Relative to glucose, pristine MPs exhibited 78.56%–90.58% of the denitrification-supporting performance, while aged MPs reached 83.17%–95.39%. This enhancement in bioavailability correlated with a 43.04–632.29% greater weight loss in aged MPs compared to pristine MPs. Compared with the control, pristine MPs increased the electron transfer efficiency by 32.29%–533.65%, and aged MPs further enhanced it by 10.26%–127.24% relative to pristine MPs. MP-carbon increased the relative contribution of bacterial denitrification from 45.80 % to 51.20 % compared to glucose. Especially, keystone bacteria (Thermosporothrix, Gemmatirosa, Daejeonella, and Geobacter) harbored genes associated with both denitrification and MPs degradation. Genome-scale metabolic models further predicted that metabolites generated from MPs degradation, including butyryl-CoA, stearoyl-CoA, benzaldehyde, and succinate, might participate in denitrification-related electron supply and denitrification reduction processes through distinct metabolic pathways. These results provide new insights into the impact of MPs on denitrification.

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解读微塑料驱动的河流反硝化作用：碳生物利用度，关键微生物和电子传递效率。

微塑料（MPs）不断进入河流，对生态造成越来越严重的威胁。MPs在老化和降解过程中逐渐释放溶解的有机碳。然而，mp释放的碳驱动沉积物反硝化的分子机制尚不清楚。本研究结合251个淡水塑球的数据和微观实验来解决这一问题。我们发现塑料球中反硝化菌丰度很高（门水平为66.65%），微观实验证实了MPs作为碳源的利用。相对于葡萄糖，原始MPs的反硝化支持性能为78.56% ~ 90.58%，而老化MPs的反硝化支持性能为83.17% ~ 95.39%。与原始MPs相比，衰老MPs的生物利用度增强与体重减轻43.04-632.29%相关。与对照相比，原始MPs的电子传递效率提高了32.29% ~ 533.65%，老化MPs的电子传递效率进一步提高了10.26% ~ 127.24%。与葡萄糖相比，mp -碳使细菌反硝化的相对贡献从45.80 %增加到51.20 %。特别是，关键细菌（热孢子菌，Gemmatirosa， Daejeonella和Geobacter）携带与反硝化和MPs降解相关的基因。基因组尺度的代谢模型进一步预测，MPs降解产生的代谢物，包括丁基辅酶a、硬脂酰辅酶a、苯甲醛和琥珀酸盐，可能通过不同的代谢途径参与反硝化相关的电子供应和反硝化还原过程。这些结果为MPs对反硝化的影响提供了新的见解。

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

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.