Novel Multienzymatic Cascade for the Conversion of Salicin From Plant Extract Into Salicylic Acid.

This study presents a novel multienzymatic strategy for the efficient and green production of valuable salicylic acid from plant-derived salicin. The biocatalytic route couples β-glucosidase for deglycosylation with laccase and xanthine oxidase (XO) for subsequent oxidation. The primary objective of this approach was to assess the feasibility of enzyme coupling within a single one-pot reaction. The results demonstrate that this strategy successfully enabled the transformation of salicylic alcohol into salicylic acid, mediated by a compatible laccase/TEMPO and XO system in a one-step process at pH 7 and 25°C. However, the integration of β-glucosidase into a one-pot system for direct salicin conversion was found to reduce the oxidative efficiency of XO, thus necessitating a sequential approach. Applying this optimized enzymatic cascade to a crude Salix purpurea bark extract initially encountered limitations in oxidation due to matrix complexity. Subsequent optimization of biocatalyst dosage delivered complete substrate oxidation and a 95% salicylic acid yield. This research significantly broadens the applicability of multienzymatic biocatalytic cascades, offering a promising and sustainable route for transforming natural compounds within complex plant extracts into high-value bioactive ingredients.