Molecular insights into effects of PBAT microplastics on latosol microbial diversity and DOM chemodiversity

The impact of biodegradable microplastics on the microbial community and dissolved organic matter (DOM) in latosol has not been well reported. In this study, an incubation experiment at 25 ºC for 120 days using latosol amended with low (5%) and high (10%) concentrations of polybutylene adipate terephthalate (PBAT) microplastics was carried out to explore the impacts of PBAT microplastics on soil microbial communities and DOM chemodiversity, and the intrinsic interactions between their shifts. The main bacterial and fungal phyla in soil, namely Chloroflexi, Actinobacteria, Chytridiomycota, and Rozellomycota showed a nonlinear relationship with PBAT concentration and played a pivotal role in shaping DOM chemodiversity. A higher decreased levels of lignin-like compounds and increased levels of protein-like and condensed aromatic compounds in the 5% treatment were observed than that in the 10% treatment. Furthermore, a higher increase relative abundance of CHO compounds in the 5% treatment than in the 10% treatment was ascribed to its higher oxidation degree. Co-occurrence network analysis suggested that bacteria formed more complex relationships with DOM molecules than fungi did, indicating their critical roles in DOM transformation. Our study has important implications for understanding the potential influence of biodegradable microplastics on carbon biogeochemical roles in soil.