Efficient mechano-enzymatic hydrolysis of polylactic acid under moist-solid conditions.

Quantitative mechano-enzymatic depolymerisation of polylactic acid to lactic acid was achieved at 55{degrees}C using the Humicola insolens cutinase enzyme in moist-solid reaction mixtures. The resulting lactic acid was easily recovered, and the crude product was pure enough to be used in further synthesis of a value-added compound, a known benzimidazole-based drug precursor. The presented mechano-enzymatic depolymerisation strategy enables the closed-loop recycling of untreated polylactic acid under mild conditions, using a renewable, non-toxic catalyst and producing minimum solvent waste.