Isolation and characterization of Pseudomonas sp. QX11 with high-efficiency aerobic denitrification for eutrophication control in aquaculture

IF 8 1区环境科学与生态学 Q1 ENVIRONMENTAL SCIENCES

Science of the Total Environment Pub Date : 2025-08-02 DOI:10.1016/j.scitotenv.2025.180187

Shanrui Shen , Yiyi Zhou , Hongli Cheng , Han Qian , Jun Wen , Chunmei Lin , Xiaofang Lai

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Abstract

Eutrophication of aquatic ecosystems, primarily induced by the excessive accumulation of nitrogen compounds from aquaculture activities, poses significant environmental challenges. To address this issue through biological denitrification, a total of 17 strains with aerobic denitrification activity were isolated from river prawn pond using selective media. Among these isolates, strain QX11 exhibited the highest denitrification activity and was consequently selected for further investigation. Phylogenetic analysis identified strain QX11 as showing highest homology (98.32 %) with Pseudomonas mendocina, with optimal growth and denitrification performance observed at a C/N ratio of 10, salinity of 5, temperature of 30 °C and rotational speed of 150 rpm. Under these optimized conditions, QX11 exhibited remarkable nitrogen removal efficiencies: achieving 98.06 % NH₄⁺-N removal when NH₄Cl served as the sole nitrogen source; 97.9 % NO₃⁻-N removal with KNO₃ as the sole nitrogen source, and simultaneous removal rates of 98.96 % NH₄⁺-N and 96.5 % NO₃⁻-N in mixed nitrogen sources (NH₄Cl and KNO₃), while accumulating only negligible amounts of NO₂⁻-N regardless of nitrogen source composition. The biosafety assessment revealed that QX11 demonstrated sensitivity to most tested antibiotics and exhibited no hemolytic activity. Experimental trials with river shrimp showed no significant difference (P > 0.05) in mortality rates between QX11-treated and control groups. In simulated aquaculture effluent treatment systems, QX11 exhibited exceptional bioremediation performance, achieving removal efficiencies of 99.74 % for NH₄⁺-N, 97.98 % for NO₃⁻-N, 99.63 % for NO₂⁻-N, and 97.44 % for COD. Notably, QX11 inoculation significantly altered the microbial community composition in the moving bed biofilm reactor (MBBR), particularly affecting the relative abundance of dominant phyla and genera. These comprehensive results demonstrate that QX11 represents an efficient and environmentally safe aerobic denitrifying bacteria, providing a promising biological solution for mitigating water eutrophication in aquaculture and treating various types of nitrogen-contaminated wastewater.

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高效好氧反硝化控制水产养殖富营养化假单胞菌QX11的分离与特性研究

水生生态系统的富营养化，主要是由水产养殖活动中氮化合物的过度积累引起的，构成了重大的环境挑战。为了解决这一问题，采用选择性培养基从河对虾池中分离出17株具有好氧反硝化活性的菌株。其中，菌株QX11的反硝化活性最高，因此被选为进一步研究的对象。系统发育分析表明，菌株QX11与mendocina假单胞菌的同源性最高（98.32%），在C/N比为10、盐度为5、温度为30℃、转速为150 rpm的条件下具有最佳的生长和反硝化性能。在此优化条件下，QX11表现出显著的脱氮效率：当NH4Cl为唯一氮源时，QX11的NH4+-N去除率达到98.06%；在混合氮源（NH4Cl和KNO3）中，NH4+-N的同时去除率为98.96%，NO3−-N的同时去除率为96.5%，而无论氮源组成如何，NO2−-N的积累量都可以忽略不计。生物安全性评价显示，QX11对大多数被试抗生素均表现出敏感性，且无溶血活性。河虾的试验结果无显著差异(P >；qx11治疗组与对照组的死亡率差异（0.05）。在模拟水产养殖出水处理系统中，QX11表现出优异的生物修复性能，对NH4+-N、NO3−-N、NO2−-N和COD的去除率分别达到99.74%、97.98%、99.63%和97.44%。值得注意的是，接种QX11显著改变了移动床生物膜反应器（MBBR）中的微生物群落组成，特别是影响了优势门和属的相对丰度。综上所述，QX11是一种高效、环保的好氧反硝化细菌，为缓解水产养殖水体富营养化和处理各类氮污染废水提供了一种有前景的生物解决方案。

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来源期刊

Science of the Total Environment 环境科学-环境科学

CiteScore

17.60

自引率

10.20%

发文量

8726

审稿时长

2.4 months

期刊介绍： The Science of the Total Environment is an international journal dedicated to scientific research on the environment and its interaction with humanity. It covers a wide range of disciplines and seeks to publish innovative, hypothesis-driven, and impactful research that explores the entire environment, including the atmosphere, lithosphere, hydrosphere, biosphere, and anthroposphere. The journal's updated Aims & Scope emphasizes the importance of interdisciplinary environmental research with broad impact. Priority is given to studies that advance fundamental understanding and explore the interconnectedness of multiple environmental spheres. Field studies are preferred, while laboratory experiments must demonstrate significant methodological advancements or mechanistic insights with direct relevance to the environment.