Submitted to: Process Biochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2006
Publication Date: 1/3/2007
Citation: Ezeji, T.C., Qureshi, N., Blaschek, H.P. 2007. Production of acetone-butanol-ethanol (ABE) in a continuous flow bioreactor using degermed corn and Clostridium beijerinckii. Process Biochemistry. 42:34-39. Interpretive Summary: In these studies, we investigated the production of butanol from degermed corn. Butanol is a superior fuel to ethanol and can be used in internal combustion engines. It can also be used as a solvent and a chemical in paint and plastic industries. Currently, butanol market in the U.S. is 2.9 billion lbs/year, which is produced from petrochemical sources. Butanol can be produced from agricultural crops (corn, rye, and barley), dairy industry byproduct (cheese whey permeate), and cellulosic residues including wheat straw, rice straw, and corn stalks. In these studies, it has been demonstrated that degermed corn/saccharified degermed corn can be used for butanol production. Use of degermed corn/saccharified degermed corn results in the production of byproducts such as germ/oil, and corn fiber which results in byproduct credit (from these byproducts), thus reducing the cost of butanol production from corn. To further reduce the cost of butanol production, a continuous process was used as opposed to the traditional batch process. Economic production of butanol from degermed corn would benefit the U.S. corn growers. Additionally, butanol end users (U.S. public; uses - fuel and chemical) would benefit from this process.
Technical Abstract: An examination of the sustainability of the long-term cultivation of Clostridium beijerinckii BA101 in degermed corn/saccharified degermed corn based P2 medium has been described in this work. It was found that long term continuous cultivation of C. beijerinckii BA101 in a degermed corn based medium was not possible due to the instability of the gelatinized degermed corn starch during storage often called “retrogradation.” Using this substrate, continuous acetone butanol ethanol (ABE) fermentation was run for 228 h when the fermentation turned acidogenic. However, continuous fermentations of saccharified degermed corn with normal and half P2 medium nutrients were successful. In saccharified degermed corn continuous fermentation, ABE concentration up to 14.28 g/L was achieved at a dilution rate of 0.03/h. This work demonstrated that byproduct (germ/oil, corn fiber) credit can be obtained by fermenting saccharified degermed corn in continuous bioreactors. Additionally, significant savings can be achieved by supplementing with half of the normal P2 medium nutrients.