Abstract
Aureobasidium pullulans converts starch into biomass by the production of glucoamylase (1,4-α-D-glucan glucohydrolase EC 3.2.1.3) only. The enzyme synthesis did not appear to depend on substrate induction; maximal enzyme activity, however, occurred after 48 h growth in YNB medium containing soluble starch as the sole carbon source. The enzyme had the following characteristics, as determined in the cell-free culture broth: optimal pH 5.75; optimal temperature 50 C; complete heat inactivation after 10 min at 60 C; apparent optimal reaction time 120 min.