Partial characterization of β‐ d‐xylosidase from wheat malts

Arabinoxylans (AXs) from wheat malts potentially affect beer quality and production. β‐ d ‐Xylosidase is a key enzyme that degrades the main chains of AXs to produce xylose. This study performed a partial characterization of β‐ d ‐xylosidase from wheat malts. The optimal temperature was 70 °C and the enzyme exhibited excellent thermostability, that is, residual activities were 92.6% at 60 °C for 1 h. The enzyme was stable over a pH range of 3.0–6.0 and showed optimum activity at pH 3.5 and 4.5. Kinetic parameters K_m and V_max of wheat malt β‐ d ‐xylosidase against p‐nitrophenyl‐xyloside were 1.74 mmol L^?1 and 0.76 m m min^?1, respectively. The enzyme activity was severely inhibited by Cu²⁺, moderately inhibited by Mn²⁺, Mg²⁺, Al³⁺, Ca²⁺, Ba²⁺ and Na⁺ and mildly inhibited by Fe³⁺ and Fe²⁺. The partial enzymatic characterization achieved in this study can be used as a theoretical basis for purifying β‐ d ‐xylosidase from wheat malts. Copyright © 2015 The Institute of Brewing & Distilling