(538e) Application of Wafer-Enhanced Electrodeionization In a Continuous Fermentation Process to Produce Butyric Acid with Clostridium Tyrobutyricum

Butyric acid is an organic acid which can be produced by fermenting sugars with Clostridium tyrobutyricum. Butyric acid has many applications in the food and perfume industries including enhancing butter-like notes in food flavors and using esters of butyric acid as additives in the perfume industry.  Although most Clostridia strains can produce butyric acid, C. tyrobutyricum is most commonly used because it can produce butyric acid with a high selectivity in a simple medium.  Fermentation with C.tyrobutyricum produces butyric acid and acetic acid as its main products, while simultaneously producing hydrogen and carbon dioxide as the gaseous products. When an inhibitory product, such as butyric acid, exists in a fermentation broth, simultaneous product removal could relieve the inhibition effect, increase cell mass, and improve fermentation productivity. The widely used separation methods for organic acids from a fermentation broth include ion exchange, liquid extraction, and electrodialysis.  The continous use of electrodeionization has not been reported with fermentation, especially with the removal of butyric acid.  This work performs this separation and finds that electrodeionization can not only increasese the selectivity of butyric to acetic acid from 85 to 92%, but also increases the productivity by 220%.  This has potential for butryic acid production as well as using butryic acid as an intermediate to make butanol.