Abstract：
Microplastics (MPs) pose an emerging threat to soil ecological function, yet effective solutions remain limited. This study introduces a novel approach using magnetic biochar immobilized PET hydrolase (MB-LCC-FDS) to degrade soil polyethylene terephthalate microplastics (PET-MPs). MB-LCC-FDS exhibited a 1.68-fold increase in relative activity in aquatic solutions and maintained 58.5 % residual activity after five consecutive cycles. Soil microcosm experiment amended with MB-LCC-FDS observed a 29.6 % weight loss of PET-MPs, converting PET into mono(2-hydroxyethyl) terephthalate (MHET). The generated MHET can subsequently be metabolized by soil microbiota to release terephthalic acid. The introduction of MB-LCC-FDS shifted the functional composition of soil microbiota, increasing the relative abundances of Microbacteriaceae and Skermanella while reducing Arthobacter and Vicinamibacteraceae. Metagenomic analysis revealed that MB-LCC-FDS enhanced nitrogen fixation, P-uptake and transport, and organic-P mineralization in PET-MPs contaminated soil, while weakening the denitrification and nitrification. Structural equation model indicated that changes in soil total carbon and Simpson index, induced by MB-LCC-FDS, were the driving factors for soil carbon and nitrogen transformation. Overall, this study highlights the synergistic role of magnetic biochar-immobilized PET hydrolase and soil microbiota in degrading soil PET-MPs, and enhances our understanding of the microbiome and functional gene responses to PET-MPs and MB-LCC-FDS in soil systems.
摘要：
微塑料（MPs）对土壤生态功能构成了新的威胁，然而，有效的解决方案仍然有限。本研究介绍了一种使用磁性生物炭固定化PET水解酶（MB-LCC-FDS）降解土壤聚对苯二甲酸乙二醇酯微塑料（PET-MPs）的新方法。MB-LCC-FDS在水溶液中的相对活性增加了1.68倍，并在连续五个循环后保持了58.5％的残留活性。用MB-LCC-FDS修正的土壤微观实验观察到PET-MPs的重量损失为29.6％，将PET转化为单(2-羟乙基)对苯二甲酸酯(MHET)。产生的MHET随后可以被土壤微生物群代谢以释放对苯二甲酸。MB-LCC-FDS的引入改变了土壤微生物群的功能组成，增加微细菌科和斯克曼氏菌的相对丰度，同时减少Arthobacter和Vicinamibacteraceae。宏基因组分析显示MB-LCC-FDS增强了固氮，P吸收和转运，PET-MPs污染土壤中的有机磷矿化，同时削弱反硝化和硝化。结构方程模型表明，土壤全碳和辛普森指数的变化，由MB-LCC-FDS诱导，是土壤碳氮转化的驱动因素。总的来说,这项研究强调了磁性生物炭固定化PET水解酶和土壤微生物在降解土壤PET-MPs中的协同作用，并增强我们对土壤系统中微生物组和功能基因对PET-MPs和MB-LCC-FDS的反应的理解。
