State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211800, PR China.
Junior Research Group Plastic Biodegradation, Department of Biotechnology and Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, Greifswald, Germany.
Chemosphere. 2022 Oct;304:135263. doi: 10.1016/j.chemosphere.2022.135263. Epub 2022 Jun 10.
Polyurethane (PU) is one of the mass-produced recalcitrant plastics with a high environmental resistance but extremely low biodegradability. Therefore, improperly disposed PU waste adds significantly to plastic pollution, which must be addressed immediately. In recent years, there has been an increasing number of reports on plastic biodegradation in insect larvae, especially those that can feed on polyethylene and polystyrene. This study revealed that yellow mealworm (Tenebrio molitor) larvae can chew and ingest polyether-PU foams efficiently, resulting in a significant mass loss of nearly 67% after 35 days at a similar survival rate compared to when fed on bran. However, polyether-PU fragments were found in the frass of T. molitor, indicating that polyether-PU biodegradation and bioconversion in intestinal tracts were not complete. The scission of ether and urethane bonds in the polyether-PU can be evidenced by comparing polymer fragments recovered from frass with the pristine ones using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Gel permeation chromatography suggested the release of low-molecular-weight oligomers as a result of the biodegradation, which also resulted in poor thermal stability of the polyether-PU foam as determined by thermogravimetric analysis. High-throughput sequencing of the gut microbiome revealed significant changes in the microbial community populations due to the polyether-PU diet, for example, an increase in the families Enterobacteriaceae and Streptococcaceae, suggesting that these microorganisms may contribute to the polyether-PU biodegradation.
聚氨酯（PU）是一种大量生产的难降解塑料，具有很高的环境抗性，但生物降解性极低。因此，处理不当的 PU 废物显著增加了塑料污染，必须立即加以解决。近年来，越来越多的关于昆虫幼虫中塑料生物降解的报道，特别是那些可以以聚乙烯和聚苯乙烯为食的幼虫。本研究表明，黄粉虫（Tenebrio molitor）幼虫可以有效地咀嚼和摄入聚醚-PU 泡沫，在与 bran 喂养相似的存活率下，35 天后其质量损失近 67%。然而，在黄粉虫的粪便中发现了聚醚-PU 碎片，这表明聚醚-PU 在肠道中的生物降解和生物转化并不完全。通过比较从粪便中回收的聚合物碎片与原始碎片，使用傅里叶变换红外光谱和 X 射线光电子能谱可以证明聚醚-PU 中醚键和氨酯键的断裂。凝胶渗透色谱表明，由于生物降解，低分子量的低聚物被释放出来，这也导致了聚醚-PU 泡沫的热稳定性变差，这可以通过热重分析来确定。肠道微生物组的高通量测序揭示了由于聚醚-PU 饮食，微生物群落的种群发生了显著变化，例如，肠杆菌科和链球菌科的数量增加，这表明这些微生物可能有助于聚醚-PU 的生物降解。
