Production of pullulan from beet molasses by Aureobasidium pullulans in a stirred tank fermentor

The effect of the aeration rate on pullulan production from beet molasses b y Aureobasidium pullulans P56 in a stirred tank fermenter was investigated. A maximum polysaccharide concentration (23 g/l), biomass dry weight (22.5 g/l), polysaccharide yield (40%) and sugar utilization (96%) was achieved a t an aeration rate of 1.0 vvm. A. pullulans grown on molasses produced a mi xture of polysaccharides. The highest value of pullulan proportion (35% of total polysaccharide) was obtained at the highest aeration condition (1.0 v vm). Apparent Viscosity of the extracellular polysaccharide increased with the increase of polysaccharide concentration and the pH, but it decreased w ith temperature. The highest value of viscosity was achieved at pH 8.0 and temperature 20 degrees C when the polysaccharide was produced by A. Pullula ns with aeration rate of 1.0 vvm. (C) 1999 Elsevier Science Ltd. All rights reserved.