M.S. Graduate: Joseph Rauzi
Advisor: Ulrike Tschirner, Ph.D. and Shri Ramaswamy, Ph.D.
Abstract: Acid crash of an acetone-butanol-ethanol (ABE) fermentation occurs when the bacterial culture fails to transition from producing intermediate acid products (acidogenesis) to producing the ABE solvent products (solventogenesis). In this project, acid crash of Clostridium acetobutylicum prevented examination of the initial project question: how much does continuous butanol removal from ABE fermentation broth accelerate butanol production? Despite attempting several acid crash control methods including lower culture temperature, pH control, titration with sodium hydroxide, and more, the cultures did not transition to solventogenesis.
After accepting the acid crash of these C. acetobutylicum batch cultures, this project transitioned to producing acid products using paper mill rejects. This paper waste stream includes processed fiber that can be enzymatically hydrolyzed to fermentable sugars. Using hydrolysate with a glucose concentration of 2.5 g/L, this C. acetobutylicum strain produced 0.7 g/L and 0.3 g/L butyric and acetic acid respectively with no additional media components added, and 0.8 g/L and 0.4 g/L respectively with Reinforced Clostridial Media components added. These results indicate potential for local renewable bio-butanol production using paper mill waste as a feedstock.
Masters Defense Seminar was held Wednesday, April 20th, 2022