Zhong Riying, Li Minqian, Zhu Ziying, Fang Xilin, Wang Xiaocui, Gong Han, Yan Muting
College of Marine Sciences, South China Agricultural University, Guangzhou, 510641, China.
College of Marine Sciences, South China Agricultural University, Guangzhou, 510641, China.
Chemosphere. 2024 Dec;369:143908. doi: 10.1016/j.chemosphere.2024.143908. Epub 2024 Dec 10.
Microplastics (MPs) contamination presents a major environmental challenge, with accumulation of thousands of tons of MPs in ecosystems worldwide posing significant risks to human health and biodiversity. Identifying bacteria capable of degrading MPs offers a promising long-term solution to this issue. While several bacterial strains have demonstrated varying degrees of plastic degradation, the mechanisms underlying these processes remain poorly understood. In this study, 16S rDNA analysis was used to screen ten bacterial strains isolated from mangrove water samples for their potential to degrade MPs. Among these, Bacillus cereus strain ZRY and Pseudochrobactrum saccharolyticum strain ZRY emerged as the most effective candidates. The degradation of polyethylene (PE) and polypropylene (PP) was monitored through weight loss measurements over a 60-day incubation period. B. cereus strain ZRY achieved weight losses of 1.1% for PE and 1.0% for PP, while P. saccharolyticum strain ZRY recorded losses of 0.6% for PE and 0.4% for PP. Morphological and structural changes during degradation were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy, and atomic force microscopy, which also identified key enzymes produced by both bacterial strains that facilitate the degradation of MPs. Additionally, the effect of pH, salt concentrations, inorganic ions, and incubation duration on degradation efficiency were evaluated. Our findings demonstrate the potential of these bacterial strains for MPs degradation, underscoring their potential for future applications in addressing MP pollution. This research lays the foundation for optimizing conditions to enhance bioremediation efforts utilizing these microbial candidates.
微塑料（MPs）污染是一项重大的环境挑战，全球生态系统中数千吨微塑料的积累对人类健康和生物多样性构成了重大风险。识别能够降解微塑料的细菌为解决这一问题提供了一个有前景的长期解决方案。虽然几种细菌菌株已表现出不同程度的塑料降解能力，但这些过程背后的机制仍知之甚少。在本研究中，利用16S rDNA分析从红树林水样中分离出的十种细菌菌株降解微塑料的潜力。其中，蜡样芽孢杆菌ZRY菌株和嗜糖假单胞菌ZRY菌株成为最有效的候选菌株。通过在60天的培养期内测量重量损失来监测聚乙烯（PE）和聚丙烯（PP）的降解情况。蜡样芽孢杆菌ZRY菌株使PE的重量损失达到1.1%，PP的重量损失达到1.0%，而嗜糖假单胞菌ZRY菌株使PE的损失为0.6%，PP的损失为0.4%。使用扫描电子显微镜、傅里叶变换红外光谱和原子力显微镜分析了降解过程中的形态和结构变化，这些分析还确定了两种细菌菌株产生的促进微塑料降解的关键酶。此外，还评估了pH值、盐浓度、无机离子和培养持续时间对降解效率的影响。我们的研究结果证明了这些细菌菌株降解微塑料的潜力，突出了它们在解决微塑料污染方面未来应用的潜力。这项研究为优化条件以加强利用这些微生物候选物的生物修复工作奠定了基础。
