微塑料在菲降解过程中对融合菌株F14的影响

以聚乙烯微塑料（Polyethylene Microplastics，PE-MPs）为对象，探究其对融合菌株F14在降解菲过程中的影响。采用扫描电镜（SEM）对添加PE-MPs前后细胞形态进行表征，结果显示，添加PE-MPs后的细胞呈现明显的凹陷，且胞外聚合物明显增多；采用傅里叶变换光谱（FTIR）对F14菌株细胞表面化学成分进行表征，发现在接触PE-MPs后，菌株细胞表面的碳水化合物、多糖和酰胺的吸收强度发生了相对变化，蛋白质、核酸、多糖的相对含量明显增加；细胞活性氧测试表明，随着PE-MPs浓度的增加和培养时间的延长，F14细胞内活性氧含量逐渐降低，PE-MPs的粒径对细胞活性氧的产生量没有明显的影响。试验浓度和粒径范围内的PE-MPs的存在并没有抑制融合菌株F14对菲的降解，反而有所促进，推测可能是PE-MPs作为载体增大了F14和菲的接触机会，同时其可能对F14菌株细胞产生了应激反应，促使F14分泌胞外聚合物，同时减弱了F14细胞的氧化损伤，进而影响了F14对菲的降解过程。

Effect of microplastics on fusion strain F14 during phenanthrene degradation

This study examined the effect of polyethylene microplastics(PE-MPs)on the degradation of phenanthrene by the fusion strain F14. Scan electron microscopy(SEM)analysis showed obvious depressions in the cell and the concentration of extracellular polymeric substances increased significantly after the addition of PE-MPs. The results of the Fourier transform infrared spectroscopy(FTIR) spectroscopy used to characterize the chemical composition of the cell surface showed that after exposure to PE-MPs, the absorption intensities of carbohydrates, polysaccharides, and amides on the surfaces of the cells in the strains changed, and the relative contents of protein, nucleic acid, and polysaccharides increased significantly. The cell reactive oxygen species(ROS)test showed that with the increase in the concentration of PE-MPs and the extension of culture time, the reactive oxygen content in the F14 cells gradually decreased. The PE-MPs particle sizes had no significant effect on the production of ROS in cells. The presence of PE-MPs within the test concentration and particle size range promoted the degradation of phenanthrene by the fusion strain F14 instead of degrading it. It is speculated that the PE-MPs acted as carriers and increased the chance of contact between F14 and phenanthrene. At the same time, however, the presence of PE-MPs may have caused a stress response in F14 strain cells, prompting them to secrete extracellular polymers that may have improved the degradation of phenanthrene.