Effect of different nitrogen sources on activities of UDPG-pyrophosphorylase involved in pullulan synthesis and pullulan production by Aureobasidium pullulans

Investigated was the effect of nitrogen source on fermentation time, pullulan production, biomass, and UDPG-pyrophosphorylase activity. Pullulan production fell when excess nitrogen source was present. Biomass accumulation increased as the level of nitrogen source raised. Pullulan production in the medium containing NaNO2 was 58.53% (w/w), greater than that with (NH4)2SO4, reaching maximum production one day earlier compared to that with (NH4)2SO4. The optimum fermentation time for pullulan production, and UDPG-pyrophosphorylase activity were also affected by the nitrogen source in the medium. UDPG-pyrophosphorylase activity was highly correlated with the increasing production rate of pullulan.