396965 Butanol Production Improvement By Metabolically Engineered Clostridium Tyrobutyricum with Proteomics Analysis

Monday, November 17, 2014
Galleria Exhibit Hall (Hilton Atlanta)
Wanqi Sun1, Chao Ma2 and Margaret Liu2, (1)Department of Food Science and Nutrition, University of Minnesota Twin Cities, St Paul, MN, (2)Department of Chemical and Biological Engineering, The University of Alabama, Tuscaloosa, AL

Some metabolically engineered clostridia have the potential to economically produce biobutanol, a sustainable and environmentally friendly fuel with similar energy intensity to petroleum gas. The goals of this study were to develop a fundamental understanding of carbon redistribution to butanol and achieve higher butanol production using engineered C. tyrobutyricum ATCC 25755. The 2-L free-cell fermentations were performed in stirred tank bioreactors at pH 6.0 and 37oC using butyrate producing strains (control) and a high butanol producing ACKKO-adhE2 mutant (butanol titer of 14-16 g/L). The global proteomics profiling of these strains were investigated and compared. It is found that, as compared to wild type, the ACKKO-adhE2 had decreased expression of thiolase (thl), 3-hydroxybutyryl-CoA dehydrogenase (hbd) and crotonase (crt) and high expression of heterologous bifunctional acetaldehyde/alcohol dehydrogenase (adhE2). These findings indicated that we could further improve butanol production by refluxing carbon to butyryl-CoA.

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