earticle

영어

For production of biomass and protease, statistical experimental methods were applied to optimize production–medium composition using a Bacillus licheniformis SCK 121057. Firstly, medium components thought to have positive effects on biosynthesis of biomass and protease were selected by preliminary experiments; one factor at a time method. Factors showing significant effects were chosen by the Plackett-Burman design. Fractional factorial design (FFD) was then used to investigate the interactive effects of the selected medium components on productivity of biomass and protease. The steepest ascent method (SAM) and response surface methodology (RSM) were employed to determine the optimal concentrations of each component for maximal production of biomass and protease. Using the optimized medium, 4.02 g/L of biomass and 161.27 U/ml of protease were produced, almost three times higher than that from the initial medium conditions. Finally, fermentation conditions were examined for production of biomass and protease in a laboratory fermentor using the optimized production medium. The maximum biomass (6.54 g/L) and protease (240.06 U/ml) were obtained at 42℃, 200 rpm, 2 vvm and pH 8.