Akarsu Ceyhun, Özdemir Sadin, Ozay Yasin, Acer Ömer, Dizge Nadir
Department of Environmental Engineering, Istanbul University-Cerrahpasa, Istanbul, Turkey.
Food Processing Programme, Technical Science Vocational School, Mersin University, Mersin, Turkey.
Environ Technol. 2023 Oct;44(24):3710-3720. doi: 10.1080/09593330.2022.2071638. Epub 2022 May 4.
There are several studies stating that many types of microplastics cannot be retained completely by conventional wastewater treatment systems. Therefore, it is necessary to prevent the discharge of these microplastics to the ecological system. The objective of this study was to investigate the biodegradation ability of two different size of PE (50 and 150 µm) by using two Gram-positive, spore-forming, rod-shaped, and motile thermophilic bacteria, called strain Gecek4 and strain ST5, which can hydrolyse starch, were isolated from the soil's samples of Gecek and Ömer hot-springs in Afyonkarahisar, Turkey, respectively. Phenotypic features and 16S rRNA analyzing of strains also studied. According to these results, Gecek4s and ST5 were identified as Gecek4s and ST5, respectively. Results showed that Gecek4s could colonise the polymer surface and cause surface damage whereas ST5 could not degrade bigger-sized particles efficiently. In addition, morphological changes on microplastic surface were investigated by scanning electron microscopy (SEM) where dimensional changes, irregularities, crack, and/or holes were detected. This finding suggests that there is a high potential to develop an effective integrated method for plastic bags degradation by extracellular enzymes from bacteria.
有几项研究表明，许多类型的微塑料不能被传统的废水处理系统完全截留。因此，有必要防止这些微塑料排放到生态系统中。本研究的目的是利用两种革兰氏阳性、形成芽孢、杆状且能运动的嗜热细菌（分别称为Gecek4菌株和ST5菌株）来研究两种不同尺寸（50和150 µm）的聚乙烯（PE）的生物降解能力，这两种细菌能够水解淀粉，分别从土耳其阿菲永卡拉希萨尔的Gecek和Ömer温泉的土壤样本中分离得到。还对菌株的表型特征和16S rRNA进行了分析。根据这些结果，Gecek4菌株和ST5菌株分别被鉴定为Gecek4s和ST5。结果表明，Gecek4s能够在聚合物表面定殖并造成表面损伤，而ST5不能有效地降解较大尺寸的颗粒。此外，通过扫描电子显微镜（SEM）研究了微塑料表面的形态变化，检测到尺寸变化、不规则、裂纹和/或孔洞。这一发现表明，利用细菌胞外酶开发一种有效的塑料袋降解综合方法具有很大潜力。
