Efficient Degradation of Consumer-Grade PLA by Commercial Savinase: Optimized Conditions and Molecular Dynamics Insights
Marija Nenadović, Marijana Ponjavić, Brana Pantelić, Maciej Guzik, Tomasz M. Majka, Georgia Sourkouni, Aleksandra Maršavelski, Jasmina Nikodinović‐Runić
Abstract
High Resolution Image Download MS PowerPoint Slide 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.