Date of Graduation

5-2015

Document Type

Thesis

Degree Name

Bachelor of Science in Chemical Engineering

Degree Level

Undergraduate

Department

Chemical Engineering

Advisor/Mentor

Clausen, Ed

Committee Member/Reader

Hestekin, Jamie A

Abstract

Clostridium saccharoperbutylacetonicum is used in ABE fermentation which historically produces a solvent mixture of 3:6:1 parts acetone, butanol, and ethanol respectively. The fermentation process undergoes two phases, an acidogenesis phase which produces butyric acid, and a solventogenic phase which reutilizes the butyric acid, making butanol. For ABE fermentation to compete economically with butanol production from petroleum, the concentration of butanol in the solvent product must be increased dramatically. Unpublished research by Carver student Kayla Kimbrough in the summer of 2012 showed that the addition of salts (sodium acetate) to PYG fermentation media increased butanol production from Clostridium saccharoperbutylacetonicum significantly. When compared to the control in this experiment, a 4 mM concentration of acetate in 20 g l-1 PYG media yielded a 400% increase in butanol concentration. This aim of this research was to confirm Kimbrough’s results and perform a mass balance to account for the acetate after the fermentation process to ensure that this rise in production was not due to the salts being utilized as a food source. Although this experiment did not have the predicted high butanol yields, the post fermentation analysis accounted for >99% of the added acetate, which suggests that the acetate is acting as a stabilizer and not as a carbon source.

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