(485e) Continuous Butanol Fermentation by Clostridium Beijerinckii ATCC 55025 in a Fibrous Bed Bioreactor

With the rising concern of limited supply of fossil fuel and fluctuating price of crude oil, researches in renewable energy is getting more and more popular. In the field of biofuel production, butanol production is one of the popular choices with its similar properties to automobile fuel. Butanol can be produced through acetone-butanol-ethanol (ABE) fermentation using agricultural commodities by clostridia. However, butanol production from ABE fermentation is limited in its low yield, productivity and titer due to the product toxicity to the microorganisms. The low titer also results in the high cost of downstream processing for the separation of butanol from the cultured media. In order to improve its productivity and titer, single-path continuous operation in a fibrous bed bioreactor (FBB) was used for reducing end-product inhibition and increasing cell growth. Continuous operation without recirculation can constantly produce butanol at high concentration with less product inhibition. Incorporation of FBB into this process is able to help cell immobilization in a fibrous matrix at a high cell density and quick adaptation of higher concentration of toxic product. The optimized parameters of the process will be presented, including the medium composition, dilution rate, and its scalability.