Production of Solvent (acetone-butanol-ethanol) in Continuous Fermentation by Clostridium saccharobutylicum DSM 13864 Using Gelatinised Sago Starch as a Carbon Source

Abstract

Solvent production by Clostridium saccharobutylicum DSM 13864 was carried out in a single stage continuous culture using 2 L stirred tank fermenter with gelatinised sago starch as a carbon source. From the study it was found that the condition could be adjusted to suit for acids production (high dilution rate and high pH) or solvent production (low dilution rate and low pH) by manipulating the dilution rate and culture pH of single stage continuous fermentation. The highest solvent concentration in outflow (9.10 g/L) was obtained at pH 4.5 and dilution rate of 0.05 h^1, which corresponds to overall productivity of 0.46 g/L.h. However, the highest total solvent productivity (0.85 g/L.h) was obtained at dilution rate of 0.11 h-1 and pH 4.5, which gave a total solvent yield of 0.29 g solvent/g sago starch. Although the total solvent productivity was greatly increased in continuous culture, the final solvent concentration attained in outflow was decreased by about 53% as compared to batch culture.

Keywords

• Acetone-butanol-ethanol fermentation
• Clostridium saccharobutylicum
• Chemostat culture
• Sago starch