Abstract: Plackett-Burman (PB) design and response surface methodology (RSM) were applied to optimize 7 medium components for pullulan production by pigment-free mutant strain UVMU3-1. The results indicated that the yield of pullulan was mainly influenced by the concentrations of glucose and KH2PO4. The components were approached to the maximum response area using steepest ascent design (SAD). Using central composite design combined with response surface methodology, the optimal medium composition was determined to be 67 g/L glucose, 5.18 g/L KH2PO4, 5 g/L (NH4)2SO4, 10 g/L NaNO3, 0.5 g/L MgSO4 ·7H2O, 2 g/L yeast extract and 10 mL/L Tween-80. The experimental yield of pullulan in the optimized medium was 19.98 g/L, which was close to the predicted value of 19.94 g/L and increased by 163% when compared with the control.

Key words: pullulan, Plackett-Burman design, response surface methodology, medium optimization