【背景】氮氧化物 (NOX) 是我国优先控制的主要空气污染物之一, 而植物在清除空气中氮氧化物方面具有重要贡献。植物叶际微生物能否提高空气中氮氧化物的清除效率仍是待解之谜, 因此, 分离筛选高效转化空气中氮氧化物的叶际微生物至关重要。【方法】本研究采用氮氧化物选择性富集培养的方法, 从常春藤叶际微生物培养物中分离筛选获得一株高效转化氮氧化物的功能菌株, 编号LZY1。通过16S rRNA基因测序、生理生化鉴定, 确定菌株的分类, 并优化其生长条件(温度、pH) , 测试其对氮氧化物的转化能力。此外, 采用烟雾箱实验, 验证该菌株对空气中氮氧化物的消减效果。【结果】研究结果表明, 菌株LZY1能够以二氧化氮 (NO2) 为唯一氮源生长。16S rRNA基因测序结果显示, 该菌株与弯曲普里斯特氏菌 (Priestia flexa) 亲缘关系最近 (相似性100%) ; 该菌株孢囊未膨大, 具有硝酸盐还原、催化酶活性、运动能力、柠檬酸盐利用和明胶液化能力, 但不进行VP反应 (Voges-Proskauer test) , 且不具备厌氧生长能力, 与Priestia flexa的代谢特性一致。菌株LZY1的适宜生长条件为30℃、pH4. 0~6. 0, 并能在较宽的pH范围 (4. 0~9. 0) 内生长。烟雾箱实验结果表明, 该菌株对空气中氮氧化物的消减速率显著高于对照组, 能够较快降低空气中NO2的浓度。【结论】从植物叶际分离筛选的LZY1菌株为Priestia flexa, 具有高效转化空气中氮氧化物的特性, 对环境的适应能力较强。研究结果为氮氧化物污染空气的生物修复提供了参考, 为大气污染治理提供了新思路。

[Background] Nitrogen oxides (NOX) are among the first major air pollutants to be regulated in China, and plants play an important role in their atmospheric NOX removal. However, whether phyllosphere microorganisms can enhance the efficiency of atmospheric NOX removal remains an open question. Therefore, the isolation and screening of phyllosphere microorganisms with high NOX conversion efficiency are of great significance. [Methods] In this study, a nitrogen oxide-selective enrichment culture method was used to isolate and screen a functional strain with high NOX conversion efficiency from the phyllosphere of Hedera helix, designated as strain LZY1. The taxonomic classification of this strain was determined through 16S rRNA gene sequencing and physiological and biochemical identification. Additionally, its growth conditions (temperature, pH) were optimized, and its NOX conversion capacity was assessed. Furthermore, an exposure experiment was conducted to verify the strain’s ability to reduce atmospheric NOX. [Results] The results showed that strain LZY1 could grow using nitrogen dioxide (NO2) as its sole nitrogen source. 16S rRNA gene sequencing revealed that this strain was most closely related to Priestia flexa (100% similarity) . The strain exhibited a colony diameter of<1 cm, no swollen sporangia, and possessed nitrate reduction ability, catalase activity, motility, citrate utilization, and gelatin liquefaction capability. However, it did not undergo the Voges-Proskauer (VP) reaction and lacked anaerobic growth capability, consistent with the metabolic characteristics of Priestia flexa. The optimal growth conditions for strain LZY1 were 30℃ and pH 4. 0-6. 0, with the ability to grow within a broad pH range (4. 0-9. 0) . The exposure experiment demonstrated that this strain significantly accelerated the reduction of atmospheric NO2 concentration compared to the control group. [Conclusion] Strain LZY1, isolated from the phyllosphere of Hedera helix, exhibits a high efficiency in converting atmospheric NOX and demonstrated strong environmental adaptability. These findings provide a reference for the bioremediation of NOX-polluted air and offer new insights into atmospheric pollution control.