Enrichment of Microbial Communities in Film Surface Soil Drives the Variation of Poly(butylene adipate-co-terephthalate) Degradation Potential in Different Types of Soils

Biodegradable mulch films have been developed as a viable solution to alleviate the growing plastic accumulation problem in soils. However, the key factors controlling the degradation speed of biodegradable mulch films remain obscure. Here, we studied the degradation performance of poly(butylene adipate-co-terephthalate) (PBAT), a promising biodegradable material, in four typical types of soils, including Lou soil (LS), Fluvo-aquic soil (CS), Black soil (BS), and Red soil (RS), through microcosms, and its association with microbiome response. The results showed that the PBAT degradation rate differed with soil type, with PBAT mineralization level of 16%, 9%, 0.3%, and 0.9% in LS, CS, BS, and RS by day 120, respectively. Metagenomic analysis revealed that microbial community of LS was more responsive to PBAT than the other three soils, and the evident degradation of PABT in LS was correlated with the significant increase of PBAT hydrolase genes. Bacteria were the dominant degraders and the enrichment of degraders in PBAT film surface soils determined PBAT degradation capacities. This work advances the understanding of microbiological mechanisms underlying the varying PBAT fate in different types of soils and will therefore have important implications for the development of microbial regulation strategy to improve PBAT biodegradation in soils.