Purification and characterization of the extracellular glucoamylase from the yeast Trichosporon adeninovorans

The yeast Trichosporon adeninovorans secretes an amylase at a high rate if grown in a medium containing starch or maltose. The enzyme was purified 29‐fold by hydroxylapatite chromatography and gel filtration and characterized as a glucoamylase. The enzyme seems to be a glycoprotein with a molecular weight of 225,000. The optimal temperature for the glucoamylase activity was 60 to 70 °C in dependence on the substrate concentration. The enzyme displayed highest activity in a pH range of 4.0–5.5 In the absence of starch or maltose the thermal stability was low but in the presence of substrate a rapid increase of the enzyme stability was observed. The Km values of the enzyme were estimated to be 1.2 g/l for soluble starch and 4 g/l for maltose.