The Characterization of the Purine Nucleoside Phosphorylase from <i>Agaricus bisporus</i> and Its Potential Application in Reducing Purine Content in Beer
2025
Jun Liu | Jian Lu
Beer, the most popular alcoholic beverage, poses health risks for individuals with gout and hyperuricemia due to its high purine content. Herein, we identified a novel purine nucleoside phosphorylase (<i>Ab</i>PNP) from the edible mushroom <i>Agaricus bisporus</i> and heterologously expressed it in <i>Pichia pastoris</i>. The recombinant <i>Ab</i>PNP exhibited optimal activity at 60 °C and pH 7.0, retaining >80% activity at pH 6.0–9.0 and >85% activity after 3 h at ≤60 °C. Kinetic analysis revealed high catalytic efficiency (kcat/Km = 2.02 × 10<sup>6</sup> s<sup>−1</sup>⋅M<sup>−1</sup>) toward inosine, with strong resistance to metal ions except for Co<sup>2+</sup> and Cu<sup>2+</sup>. The application of <i>Ab</i>PNP (1.0–5.0 U/mL) during wort saccharification reduced purine nucleosides by 33.54% (from 151.53 to 100.65 mg/L) while increasing yeast utilization of free purine bases. The resulting beer showed improved fermentation performance (alcohol content increased by 3.6%) without compromising flavor profiles. This study provides the food-grade enzymatic strategy for low-purine beer production, leveraging the GRAS status of both <i>A. bisporus</i> and <i>P. pastoris</i>.
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