Ding Zi-Yue, Yuan Zi-Wang, Hua Zi-Wei, Hu Xiao-Yue, Chai Chun-Yue, Zhang Lin, Xi Zhi-Wen, Wang Tie-Jun, Niu Qiu-Hong, Zhang Hao
College of Life Science, Research Center of Henan Provincial Agricultural Biomass Resource Engineering and Technology, Henan International Joint Laboratory of Soil Health and Water Security, Nanyang Normal University, Nanyang 473061, PR China.
Henan Province Engineering Technology Research Center of Animal Disease Control and Prevention, Nanyang Vocational College of Agriculture, Nanyang 473000, PR China.
Ecotoxicol Environ Saf. 2025 Sep 15;303:118917. doi: 10.1016/j.ecoenv.2025.118917. Epub 2025 Aug 23.
Carbendazim persists in soil, causing harm to the environment. Microbial degradation is a main way to remove carbendazim from soil, and polyethylene (PE), as a kind of microplastics, widely exists in soil. However, the mechanism by which PE influences carbendazim biodegradation is still unclear. This study isolated Rhodococcus sp. XY-1, a highly efficient carbendazim-degrading bacterium capable of completely degrading 50 mg·L carbendazim, as its sole carbon and nitrogen source within 4 d. Scanning electron microscopy revealed that PE (700 µm, 5 %) depressed XY-1 cell surfaces but induced protective intercellular substance adhesion. According to cellular reactive oxygen species (ROS) assays and Fourier transform infrared spectroscopy, PE exposure increased intracellular ROS levels in XY-1 and enhanced the absorption intensity of characteristic protein and nucleic acid peaks, indicating metabolic stimulation. Consequently, PE accelerated carbendazim degradation by strain XY-1, achieving a 79.0 % removal of 50 mg·L carbendazim within 60 h. Furthermore, PE itself underwent oxidation and hydrolysis, as evidenced by the simulated soil experiments at an increased carbon-to-oxygen ratio (from 0.016 to 0.072) and the emergence of -OH functional groups. PE also enhanced soil microbial activity, regulated organic carbon content, and influenced carbendazim adsorption, collectively promoting its degradation. Under PE (700 µm, 5 %) amendment, strain XY-1 achieved a degradation rate of 58.0 % for 5.0 mg·kg carbendazim within 7 d in soil. This study elucidates the mechanism by which microplastics influence the microbial degradation of soil organic pollutants.
多菌灵在土壤中持续存在，对环境造成危害。微生物降解是从土壤中去除多菌灵的主要途径，而聚乙烯（PE）作为一种微塑料，广泛存在于土壤中。然而，PE影响多菌灵生物降解的机制仍不清楚。本研究分离出红球菌属XY-1，这是一种高效的多菌灵降解菌，能够在4天内将50 mg·L的多菌灵作为唯一碳源和氮源完全降解。扫描电子显微镜显示，PE（700 µm，5%）使XY-1细胞表面凹陷，但诱导了细胞间保护性物质的粘附。根据细胞活性氧（ROS）测定和傅里叶变换红外光谱，PE暴露增加了XY-1细胞内的ROS水平，并增强了特征性蛋白质和核酸峰的吸收强度，表明有代谢刺激作用。因此，PE加速了菌株XY-1对多菌灵的降解，在60小时内实现了对50 mg·L多菌灵79.0%的去除率。此外，PE自身发生了氧化和水解，这在碳氧比增加（从0.016增加到0.072）的模拟土壤实验以及-OH官能团的出现中得到了证明。PE还增强了土壤微生物活性，调节了有机碳含量，并影响了多菌灵的吸附，共同促进了其降解。在添加PE（700 µm，5%）的情况下，菌株XY-1在土壤中7天内对5.0 mg·kg多菌灵的降解率达到了58.0%。本研究阐明了微塑料影响土壤有机污染物微生物降解的机制。
