Vezzini_2025_Bioresour.Technol_443_133908

The growing use of thermoplastic starch (TPS)-based bioplastics needs efficient strategies to ensure their complete biodegradation within organic waste management systems. This study introduces a novel approach using raw cell-free supernatants (CFS) containing recombinant enzymes to accelerate the hydrolysis of TPS-containing bags during anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). Recombinant amylases were screened for activity under AD-relevant conditions and Aspergillus terreus alpha-amylase (AteA) exhibited remarkable stability and activity at neutral-to-alkaline conditions, retaining 90 % activity at pH 7 compared to optimal pH 5. The combination of AteA, Talaromyces emersonii glucoamylase (TemG), and a cutinase-like enzyme (CLE) achieved 40 % weight loss of TPS-containing bags after 168 h. When applied in biochemical methane potential assays, the enzymatic cocktail increased methane yield to 250 NmL CH(4)/gVS, an enhancement of over 50 % relative to the untreated control. This improvement was associated with bioplastic hydrolysis, improved OFMSW breakdown of organic matter, and conversion of CFS-derived metabolites into biomethane. These findings establish a robust proof of concept for enzymatic treatment as an effective strategy to valorise TPS-based bioplastics. Further research should focus on optimizing enzyme loading, improving cell-free supernatant formulations, and integrating the process into industrial-scale anaerobic digestion systems to ensure technical and economic feasibility.