The toxicities of sodium perfluorononyloxy-benzenesulfonate (OBS) to animals and plants are similar to those of perfluorooctane sulfonate. However, the mechanism of its toxicity to aerobic denitrifying bacteria is still unclear. In the present study, the ecotoxicity of OBS on an aerobic denitrifying strain, Pseudomonas stutzeri, was evaluated. The results showed that a dosage of OBS clearly affected the growth and aerobic denitrification of P. stutzeri. When compared with an unamended control, the degradation efficiency of the total nitrogen decreased by 30.13% during exposure to 200 mg/L of OBS, and the complete degradation time of nitrate-nitrogen was delayed by 4 h. The lactate dehydrogenase and superoxide dismutase produced by the bacteria increased with the concentration of OBS, and reactive oxygen species were also detected by confocal laser scanning microscope imaging. Transmission electron microscope imaging revealed chromosome deformation of the cells and damage to cell content; moreover, outer membrane vesicles were secreted from the bacteria, which was the important detoxification mechanism of P. stutzeri to OBS. Expression of the genes involved in aerobic nitrification and oxidative stress were also changed under OBS stress, which further confirmed the toxicity of OBS to P stutzeri. This study reveals the environmental exposure risk of OBS from the perspective of microorganisms.

全氟壬基氧基苯磺酸钠（OBS）对动植物的毒性与全氟辛烷磺酸的相似。然而，其对好氧反硝化细菌的毒性机理仍不清楚。在本研究中，评估了OBS对好氧反硝化菌株Pseudomonas stutzeri的生态毒性。结果表明，OBS的剂量明显影响斯图氏假单胞菌的生长和有氧反硝化作用。与未经修正的对照相比，在暴露于200 mg / L的OBS期间，总氮的降解效率降低了30.13％，硝酸盐-氮的完全降解时间延迟了4 h。细菌产生的乳酸脱氢酶和超氧化物歧化酶随OBS浓度的增加而增加，并且通过共聚焦激光扫描显微镜成像还可以检测到活性氧。透射电子显微镜成像揭示了细胞的染色体变形和对细胞含量的损害。此外，细菌分泌了外膜囊泡，这是斯图氏假单胞菌重要的排毒机理。到OBS。在OBS胁迫下，有氧硝化和氧化应激相关基因的表达也发生了变化，这进一步证实了OBS对Stutzeri的毒性。这项研究从微生物的角度揭示了OBS的环境暴露风险。