Extractive acetone-butanol-ethanol fermentation using methylated crude palm oil as extractant in batch culture of Clostridium saccaharoperbutylacetonicum N1-4 (ATCC 13564)

The possibility of employing methylated crude palm oil (CPOE) as an extraction solvent to reduce end-product inhibition and to enhance solvent productivity in acetone-butanol-ethanol (ABE) fermentation was evaluated using oleyl alcohol as the standard butanol extractant. Fermentation was carried out at an initial glucose concentration of 90 g/l. CPOE did not inhibit the growth of the fermentative organism. Without solvent extraction, butanol production ceased after 30 h at a concentration of 15.4 g/l limiting cell growth to 3.98 g/l and glucose consumption to 62%. Applying CPOE as the extraction solvent, about 47% of the total butanol produced was extracted, glucose consumption was increased to 83% and relatively high glucose consumption rates and solvent productivities were obtained. Butanol production increased to 20.9 g/l; total ABE solvents and yield also increased from 21.2 g/l and 38% (in conventional fermentation) to 29.8% g/l and 40.4% respectively.