A Thermally Active Tannase from Tea Endophyte Paraburkholderia pallida Exhibits High Specificity for Galloylated Catechins.

Tannases hydrolyze ester bonds in hydrolyzable tannins and galloylated compounds with significant applications in food and agricultural industries. However, the diversity of tannase activities among tea plant-associated bacteria remains underexplored. Here, we identified Tanpp, a novel tannase/feruloyl esterase from the endophyte Paraburkholderia pallida XY820. Tanpp displayed optimal activity against (-)-epigallocatechin 3-gallate (EGCG) at 60 °C and pH 6.0, with thermal activation upon brief preincubation at 40-45 °C. The enzyme demonstrated high specificity for galloylated catechins. Structure-guided mutagenesis yielded Y338A and R304A variants with 3.09- and 1.89-fold increased catalytic efficiency toward EGCG, respectively. This work advances our understanding of tannase function within tea plant microbial communities and positions Tanpp and its engineered derivatives as promising biocatalysts for tea polyphenol biotransformation and functional food applications.