High pullulan yield is related to low UDP-glucose level and high pullulan-related synthases activity in Aureobasidium pullulans Y68

Abstract

Effects of different pH and carbon sources on pullulan production, UDP-glucose level and pullulan-related synthases activity in Aureobasidium pullulans Y68 were examined. It was found that more pullulan was produced when the yeast strain was grown in the medium with initial pH 7.0 than when it was grown in the same medium with constant pH 6.0. The results also show that higher pullulan yield was obtained when the cells were grown in the medium containing glucose than when they were cultivated in the medium supplementing other carbon sources. Our results demonstrate that the more pullulan was synthesized, the less UDP-glucose was left in the cells of A. pullulans Y68. However, it was observed that more pullulan was synthesized; the cells had higher pullulan-related synthase activity. Therefore, high pullulan yield was related to low UDP-glucose level and high pullulan-related synthases activity in Aureobasidium pullulans Y68.