Application of Wafer-Enhanced Electrodeionization in a Continuous Fermentation Process to Produce Butyric Acid with Clostridium tyrobutyricum

Abstract

Butryic acid is an organic acid which can be produced from Clostridium tyrobutyricum. This organic acid has many applications in food and perfumes as well serving as the first step in a two-step butanol production process. However, the fermentation is product inhibited as well as producing by-products of acetic acid and lactic acid. Electrodialysis and electrodeionization were explored as ways to separate butyric acid from a fermentation broth, in situ. For butyric acid system, the current resistance for ED was almost half that of EDI indicating that ED might be a better option for a pure component separation. However, in a simulated broth containing butyric, lactic, and acetic acid, the opposite trend was found to be true. These results were used to design a fermentation experiment where ED and EDI were used to separate butyric acid from an actual fermentation. It is shown that the percentage of butyric acid (compared to other organic acids) is 84%, 85%, and 92% for no separation, ED, and EDI, respectively. Further, the productivity rate is enhanced by almost 220% when comparing EDI to no separation indicating that it may make sense to use EDI for the separation of butyric acid from a Clostridium tyrobutryicum fermentation.