Effect of Medium Composition On Butanol and 1,3-Propanediol Production by Clostridium Pasteurianum DSM525

In this study, the effect of glycerol concentration, butanol concentration, co-substrate, and pH on product formation by Clostridium pasteurianum DSM525 was investigated. Glycerol concentration higher than 60 g/L inhibited cell growth and butanol production. When more than 8 g/L of butanol concentraion was added initially, C. pateurianum DSM525 did not grow at all. The addition of butyrate was found to enhance butanol production by more than 50%, while there was no significant effect of acetate on butanol production. When pH-buffering agent was added to prevent over-acidification during batch cultivation, butanol production was higher than 1,3-PD production. Without MES addition, however, butanol concentration was lower than 1,3-PD. Respose Surface. The medium composition for butanol production by C. pasteurianum DSM525 was optimized using response surface methodology (RSM). Three factors (FeSO4•7H2O, yeast extract, (NH4)2SO4) were identified to affect butanol production significantly using a fractional factorial design (FFD). Steepest ascent experiments were applied to estimate the optimal region of the three factors and the central composite experimental design (CCD) was adopted to determine their optimized values. After incubating 48 hours in the optimal composition medium, the final butanol concentration was 5.8 g/L which was higher than butanol production (4.5 g/L) with the modified P2 medium.