Expression of a Recombinant Cholesterol Esterase from <i>Mustela putorius furo</i> in <i>Pichia pastoris</i> and Its Applicability for γ-Oryzanol Hydrolysis

Ferulic acid (FA) exhibits antioxidant and anti-inflammatory properties, making it valuable for numerous industrial applications. Traditionally, FA is produced by the alkaline hydrolysis of <i>γ</i>-oryzanol, which is typically associated with wastewater generation. Recently, an increasing demand of natural FA necessitates its green production via enzymatic hydrolysis of <i>γ</i>-oryzanol, a mixture comprising triterpene alcohol ferulates and phytosteryl ferulates. Thus far, <i>γ</i>-oryzanol can be hydrolyzed by only four commercial cholesterol esterases with low yields. Herein, we report a recombinant cholesterol esterase from <i>Mustela putorius furo</i> (MPFCE) for the enzymatic hydrolysis of <i>γ</i>-oryzanol. The enzyme yielded 25.5% FA, which is the highest reported through enzymatic means thus far. The hydrolysis profile revealed that the enhanced yield primarily resulted from the near-complete hydrolysis of phytosteryl ferulates, together with slight hydrolysis of triterpene alcohol ferulates. MPFCE serves as a potential candidate for the enzymatic production of FA through targeted hydrolysis of <i>γ</i>-oryzanol.