Modeling of pullulan fermentation by using a color variant strain of Aureobasidium pullulans

Pullulan, which is comprised of glucose units, is a simple linear polysaccharide produced by Aureobasidium pullulans. Pullulan has long been used in various applications such as blood plasma substitutes, food additives, adhesive additives, flocculants, and even environmental pollution control agents. Mathematical models of biomass, pullulan, and sucrose profiles during fermentation not only provide information about the kinetic-metabolic nature of pullulan, but also facilitate the control and optimization of pullulan production. In this study, several models were modified and tested in order to describe biomass, pullulan, and sucrose profiles during batch fermentation using a color variant strain of A. pullulans. The results demonstrated that the modified Gompertz model can serve as a universal equation to fit biomass production, pullulan production, and sucrose consumption. Furthermore, validation of this modified Gompertz model indicated that biomass (slope = 1.00, R2 = 0.991), pullulan (slope = 1.10, R2 = 0.991), and sucrose (slope = 0.96, R2 = 0.991) were all predicted accurately.