Efficient Degradation of Consumer-Grade PLA by Commercial Savinase: Optimized Conditions and Molecular Dynamics Insights

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Abstract
Poly­(lactic acid) (PLA) is the most widely produced biopolymer globally, with 920,000 tons reaching the market in 2024. Although it is a biobased polymer and biodegradable, it currently poses a threat by generating a considerable waste stream in the environment unless its end-of-life options are further developed. Biorecycling of PLA is a promising solution and is critical for PLA to be a truly sustainable alternative to conventional plastics, further enabling the (bio)­plastics circular economy. This work investigates the repurposing of commercial Savinase 12T preparation, already produced on a large scale for the detergent industry, for the degradation of consumer-grade PLA. Savinase-degraded postconsumer PLA single-use cups at a rate of 166 mg·day–1·mg enzyme–1 for the lid part (crystallinity (X c) 22.9%) and 40 mg·day–1·mg enzyme–1 for the body part (X c 42.0%). The average degradation rate of PLA 3D printer filaments was determined to be 56 mg·day–1·mg enzyme–1 under optimized conditions of pH 8.5 and 42 °C. Lactic acid was identified as the main PLA degradation product of Savinase depolymerizing activity. Molecular modeling revealed Asn155 and Ser125 as key residues involved in PLA tetramer binding.
Funding Information
  • Instytut Katalizy i Fizykochemii Powierzchni im. Jerzego Habera, Polskiej Akademii Nauk
  • NextGenerationEU (NPOO.C3.2.R2-I1.06.0041)
  • Alliance of International Science Organizations (ANSO-CR-PP-2022-01)

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