Enzymatic Degradation of PBAT: Toward a Sustainable Strategy for Polyester Waste Recycling

Polymers have become indispensable in modern life and the global economy due to their low cost, high performance, and ease of processing. However, poor end-of-life management has led to widespread plastic pollution and significant resource loss. Among synthetic polyesters, polyethylene terephthalate (PET) and poly(butylene adipate-co-terephthalate) (PBAT) are widely used due to their durability, lightweight nature, and cost-effectiveness. In agriculture, PBAT-based mulch films are frequently employed to improve soil quality and crop yield. While PBAT is classified as a compostable polyester and is structurally more susceptible to enzymatic degradation than polymers with carbon-carbon backbones, its natural degradation rate in the environment remains relatively slow. Bio-based degradation using renewable biological agents such as enzymes or microorganisms presents a sustainable and environmentally friendly strategy to reduce and recycle plastic waste [1]. In this study, we investigated the enzymatic degradation of PBAT using a series of polyester hydrolases, including HiC, LCC, DmPETase, Se1JFR, and FoCut. An initial screening was performed on powdered PBAT to assess the degradation efficiency of each enzyme, with a focus on the release of monomeric degradation products. The extent of degradation was evaluated through high-performance liquid chromatography (HPLC) and mass loss measurements [2]. Following the screening phase, enzymatic degradation experiments were scaled up using commercial PBAT-based mulch film, applying the most promising enzymes identified in the preliminary tests. The degradation products were further characterized through a combination of thermal analysis (TGA and DSC), spectroscopic analysis (ATR-FTIR) and molecular weight distribution (GPC), in addition to monomer release and mass loss quantification. Overall, this study highlights the potential of enzymatic depolymerization as a bio-based strategy for PBAT waste valorization, offering a sustainable alternative to conventional disposal methods.