University of Turin, Department of Life Sciences and Systems Biology, Mycotheca Universitatis Taurinensis, Viale P.A. Mattioli 25, 10125, Turin, Italy.
University of Turin, Department of Chemistry, Via P. Giuria 7, 10125, Turin, Italy; Present Affiliation: Italian National Research Council, Institute of Intelligent Industrial Technologies and Systems for Advanced Manifacturing, Corso Giuseppe Pella 16, 13900, Biella, Italy.
Environ Pollut. 2021 Apr 1;274:116548. doi: 10.1016/j.envpol.2021.116548. Epub 2021 Jan 25.
Polyethylene (PE) is the most abundant non-degradable plastic waste, posing a constant and serious threat to the whole ecosystem. In the present study, the fungal community of plastic wastes contaminating a landfill soil has been studied. After 6 months of enrichment, 95 fungi were isolated, mostly belonging to the Ascomycota phylum. They were screened under in vitro condition: most of fungi (97%) were capable of growing in the presence of PE powder (5-10 g L) as sole carbon source. Fusarium strains better tolerated high concentration of PE. Up to 13 strains were chosen for further degradation trails, where the process was monitored by respirometry tests and by observing changes in PE chemical and physical structure by FTIR analysis and SEM images. Major results were observed for Fusarium oxysporum, Fusarium falciforme and Purpureocillum lilacinum, as they caused strong oxidation phenomena and changes in the PE film morphology. Results suggested that the initial oxidation mechanisms targeted first the methyl terminal groups. Changes in the infrared spectra were strongly strain-dependent, denoting the activation of different degradation pathways. Through the SEM analysis, the actual damages provoked by fungi were observed, including swellings, pits and furrows, bumps and partial exfoliations. Considering the rising concern about plastic disposal worldwide, the ability of these fungi to colonize PE and utilize it as carbon source is of great interest, as no pretreatments and pro-oxidant stimulants were needed.
聚乙烯（PE）是最丰富的不可降解塑料废物，对整个生态系统构成持续而严重的威胁。本研究对污染垃圾填埋场土壤的塑料废物中的真菌群落进行了研究。经过 6 个月的富集，分离出 95 株真菌，主要属于子囊菌门。在体外条件下对它们进行了筛选：大多数真菌（97%）能够在含有 5-10g/L 的 PE 粉末作为唯一碳源的情况下生长。镰刀菌菌株能够更好地耐受高浓度的 PE。选择了 13 株菌进行进一步的降解试验，通过呼吸计试验和通过傅里叶变换红外（FTIR）分析和扫描电子显微镜（SEM）图像观察 PE 化学和物理结构的变化来监测该过程。观察到强氧化现象和 PE 薄膜形态的变化，主要来自于尖孢镰刀菌、镰孢菌和紫色毛壳菌。结果表明，初始氧化机制首先针对甲基端基。红外光谱的变化强烈依赖于菌株，表明不同降解途径的激活。通过 SEM 分析，观察到真菌实际造成的损害，包括肿胀、凹坑和凹槽、凸起和部分剥落。考虑到全球对塑料处理的日益关注，这些真菌能够定殖 PE 并将其用作碳源的能力非常令人感兴趣，因为不需要预处理和促氧化剂刺激。
