Immobilization of a Recombinant Cholesterol Esterase from Mustela putorius furo for the Hydrolysis of γ-Oryzanol

Ferulic acid is a valuable phytochemical with numerous industrial applications. To fulfill the increasing demand for natural ferulic acid, a cholesterol esterase fromMustela putorius furo(MPFCE) has recently been identified to catalyze the hydrolysis of γ-oryzanol to produce ferulic acid. Herein, we report the immobilization of MPFCE onto a Ni-IDA resin with high enzyme loading and enzyme activity recovery. The metal affinity immobilization with Ni-IDA resin serves to simultaneously purify and immobilize MPFCE in one step. The resulting Ni-IDA-MPFCE biocatalyst gave high specific enzyme loading (50 mg enzyme/g carrier), a specific activity of 3.80 U/g protein, and 43% of activity recovery. It also displayed higher activity retention than that of the free enzyme under high pH, acetone content, and temperature. By using the Ni-IDA-MPFCE biocatalyst in the optimized condition of 6% (v/v) acetone, 18 mM sodium taurocholate, and 25 °C, 23.5% ferulic acid can be obtained in the first cycle. After seven cycles, the Ni-IDA-MPFCE biocatalyst also shows excellent recyclability with a high productivity of 94.5%.