The Effect of Initial Butyric Acid Addition on ABE Fermentation by C. acetobutylicum NCIMB 619

Abstract

The addition of organic acids to the growth medium has been shown to stimulate solvent production and protect against the degeneration of ABE-producing clostridia. The objective of this study is to demonstrate the effect of introduction of butyric acid in the fermentation media on the solvent production by C. acetobutylicum NCIMB 619. In this study, batch cultures were carried out in Reinforced Clostridial Media (RCM) containing 0.0015, 2.0 and 5.0 g/l of butyric acid, simultaneously with a control media (without addition of butyric acid) at 37°C for 72 hours. Samples were periodically withdrawn for analysis purposes. It was found that the presence of butyric acid during the early stage of the fermentation process favor the solvent yield to glucose utilization and productivity up to 139%. By adding butyric acid, the concentration of acetone, butanol and ethanol generated was improved significantly. In the case of 5.0 g/l butyric acid addition, acetone, butanol and ethanol production was increased approximately 92, 8 and 2 folds, respectively compared to control culture. The result obtained in this study showed that the addition of butyric acid has successfully enhanced the cell growth and subsequently promoted solvent production by C. acetobutylicum NCIMB 619.