Biobutanol Production Using Clostridium Tyrobutyricum By Integrating Metabolic Engineering and Process Development

Biobutanol Production from Clostridium tyrobutyricum by Integrating Metabolic Engineering and Process Development

 

Elizabeth Parcher^a, Chao Ma^b, Margaret Liu^b

 

a. Cornell University, School of Chemical and Biomolecular Engineering, Ithaca, NY

b. The University of Alabama, Department of Chemical and Biological Engineering, Tuscaloosa, AL

Designing a process that uses genetically engineered microorganism to produce biofuel comparable to petroleum-based fuel would facilitate society’s transition into using more carbon-neutral practice by allowing the use of current engines and infrastructure without modification. Biobutanol has great potential to replace petroleum-based fuels due to its high-energy content, low volatility, and its ability to be converted to diesel and jet fuel. The goal of this research was to achieve high production (concentration and yield) of biobutanol through gene regulation and bioreactor process development. First, Clostridium tyrobutyricum, an acidogenic clostridium with straightforward metabolic pathway that converts glucose to biochemicals such as butyric acid, was engineered to produce a high level of biobutanol and reduce the accumulation of byproducts. Specifically, the butanol enhancement gene F was cloned and introduced to C. tyrobutyricum/pMAD72 to further increase butanol production. Second, the inhibitory components in medium were identified and their concentration was minimized, which improved the final concentration of biobutanol by 32%. Third, the 3-L fermentation was performed to optimize bioreactor parameters and shift metabolic flux towards biobutanol. In fed-bath free-cell fermentation, 11 g/L of biobutanol and 8 g/L of butyric acid were obtained. Our results indicate that butanol can be economically produced by metabolically shifting carbon and energy flux by integrating metabolic engineering and process development.  

Authors:

Elizabeth Parcher

Cornell University

School of Chemical and Biomolecular Engineering

Ithaca, NY

(Email): ejp75@cornell.edu

(Phone): 858-926-8346

Chao Ma

Department of Chemical and Biological Engineering

The University of Alabama

301 7^th Avenue, Hauser Hall R116

Tuscaloosa, AL 35405

(Email): cma3@crimson.ua.edu

(Phone): 205-292-8115

Margaret Liu, PhD

Assistant Professor

Department of Chemical and Biological Engineering

The University of Alabama

301 7^th Avenue, Hauser Hall R116

Tuscaloosa, AL 35405

(Email): mliu@eng.ua.edu

(Phone): 205-348-0868