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 Cu 2+ , moderately inhibited by Mn 2+ , Mg 2+ , Al 3+ , Ca 2+ , Ba 2+ and Na + and mildly inhibited by Fe 3+ and Fe 2+ . 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