Ji Junbin, Pei Jing, Ding Fanghui, Zeng Caiting, Zhou Jie, Dong Weiliang, Cui Zhongli, Yan Xin
Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; Nanjing Key Laboratory of Quality and Safety of Agricultural Products, College of Food Science, Nanjing XiaoZhuang University, Nanjing, Jiangsu 211171, China.
Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
Environ Res. 2024 May 15;249:118468. doi: 10.1016/j.envres.2024.118468. Epub 2024 Feb 13.
Microorganisms have the potential to be applied for the degradation or depolymerization of polyurethane (PU) and other plastic waste, which have attracted global attention. The appropriate strain or enzyme that can effectively degrade PU is the key to treat PU plastic wastes by biological methods. Here, a polyester PU-degrading bacterium Bacillus sp. YXP1 was isolated and identified from a plastic landfill. Three PU substrates with increasing structure complexities, including Impranil DLN, poly (1,4-butylene adipate)-based PU (PBA-PU), and polyester PU foam, were used to evaluate the degradation capacity of Bacillus sp. YXP1. Under optimal conditions, strain YXP1 could completely degrade 0.5% Impranil DLN within 7 days. After 30 days, the weight loss of polyester PU foam by strain YXP1 was as high as 42.1%. In addition, PBA-PU was applied for degradation pathway analysis due to its clear composition and chemical structure. Five degradation intermediates of PBA-PU were identified, including 4,4'-methylenedianiline (MDA), 1,4-butanediol, adipic acid, and two MDA derivates, indicating that strain YXP1 could depolymerize PBA-PU by the hydrolysis of ester and urethane bonds. Furthermore, the extracellular enzymes produced by strain YXP1 could hydrolyze PBA-PU to generate MDA. Together, this study provides a potential bacterium for the biological treatment of PU plastic wastes and for the mining of functional enzymes.
微生物具有降解或解聚聚氨酯（PU）及其他塑料废弃物的潜力，这已引起全球关注。能够有效降解PU的合适菌株或酶是采用生物方法处理PU塑料废弃物的关键。在此，从一个塑料垃圾填埋场分离并鉴定出一株可降解聚酯PU的芽孢杆菌属细菌Bacillus sp. YXP1。使用三种结构复杂性递增的PU底物，包括英普朗尼尔DLN、聚（1,4 - 丁二醇己二酸酯）基PU（PBA - PU）和聚酯PU泡沫，来评估Bacillus sp. YXP1的降解能力。在最佳条件下，菌株YXP1能够在7天内完全降解0.5%的英普朗尼尔DLN。30天后，菌株YXP1使聚酯PU泡沫的重量损失高达42.1%。此外，由于PBA - PU的组成和化学结构清晰，将其用于降解途径分析。鉴定出PBA - PU的五种降解中间产物，包括4,4'-亚甲基二苯胺（MDA）、1,4 - 丁二醇、己二酸以及两种MDA衍生物，这表明菌株YXP1可通过酯键和脲键的水解使PBA - PU解聚。此外，菌株YXP1产生的胞外酶能够水解PBA - PU生成MDA。总之，本研究为PU塑料废弃物的生物处理及功能酶的挖掘提供了一种潜在的细菌。
