Study of acetoin reductase from Kluyveromyces marxianus

Abstract

Acetoin reductase (EC 1.1.1.4) from Kluyveromyces marxianus var. marxianus NRRL Y‐1196 was found to possess the highest specific activity (3.64 units/mg protein) of the four cultures studied. The enzyme was NADH‐dependent and catalysed the conversion of acetoin to 2,3‐butanediol. It was stable at 40°C for 30 min, but lost 50% cf its activity after 15 min at 50°C. The optimum pH for the enzymatic reduction of acetoin was 7.0. The Km values of the crude enzyme for acetoin and NADH were determined to be 0.57 mmol/l and 0.045 mmol/l, respectively.