Adaptation and Selection of Microbial Communities during Multiyear Biodegradable Plastic Mulching in Field Soils and Implications for Remediation

The pervasive environmental impact of conventional nonbiodegradable plastics has spurred interest in biodegradable alternatives, such as polybutylene adipate terephthalate (PBAT). However, the impact of its long-term use on ecosystems and the degradation efficiency in natural soils remain key considerations. Here, we investigated the dynamic changes in soil microbial communities in response to multiyear PBAT use (1-3 years) and identified key microorganisms capable of degrading PBAT. PBAT exposure significantly affected the composition and diversity of the soil microbial communities. Network analysis showed increased complexity and connectivity in both bacterial and fungal communities in multiyear PBAT-treated soils, with bacteria showing progressively intensified interactions, while fungi exhibited initial disruption, followed by recovery and functional reorganization. In addition, we found a positive correlation between the abundance of active PBAT degraders (CFU/g of soil) and the duration of mulching. A total of 10 PBAT-degrading strains belonging to the Pseudomonadota and Actinomycetota phyla were isolated from the soils. Furthermore, by utilizing the high-throughput artificial selection technology, we constructed a bacterial consortium with enhanced degradation activity, highlighting the potential of artificial selection as a robust strategy for environmental remediation efforts. Overall, this study provides insights into mitigating the impact of biodegradable mulch residues.