Collaborative Research: Investigating and Improving the Production of Butanol by C. Pasteurianum for the Value-Added Conversion of Biodiesel-Derived Crude Glycerol

University Of Alabama In Huntsville, Huntsville AL

Investigators

Abstract

0966846/0966818 Taconi/Bothun As the price of crude oil continues to reach record highs, biorefining becomes a necessary option for renewable fuels and chemical production. However, robust and versatile microorganisms for bioconversion that can utilize multiple feedstocks are currently lacking. Better engineered microorganisms designed to function within an integrated biorefining system are required to significantly reduce petroleum utilization and develop a diverse portfolio of biomass-based processes that can generate comparable alternatives for a wide range of petroleum products. Utilization of biodiesel-derived crude glycerol for the production of butanol represents a tangible approach to improving the sustainability of the biofuels industry in general and is critical for the growth and stability of the biodiesel industry in particular. Furthermore, utilizing crude glycerol as an alternative to corn-derived feedstocks will provide much-needed diversity and flexibility to an emerging biorefining industry limited by the price and availability of corn. Butanol is a key biorefinery platform chemical and has significant advantages as a renewable transportation fuel. The potential to generate higher yields using an essentially no-cost feedstock strengthens the technical and economic feasibility for industrial-scale butanol fermentation. Intellectual Merit The goal of this research is to quantify metabolism and tolerance in Clostridium pasteurianum and to engineer this bacterium to improve the value-added conversion of biodiesel-derived crude glycerol using anaerobic fermentation. This project will focus on fundamental research to understand and improve the metabolic pathways that control glycerol utilization and substrate formation from both extracellular and intracellular approaches. The proposed research has three objectives. The first objective is to elucidate the cellular response of C. pasteurianum to both substrate and product toxicity. The second objective is to evaluate cell membrane structure and stability in response to increasing concentrations of substrate impurities and butanol. And the third objective is to metabolically engineer C. pasteurianum to increase butanol production. The research is innovative because it proposes an alternative pathway to glycerol fermentation, where metabolic engineering approaches are used to knock down the genes in the reductive pathway as opposed to up-regulation of genes in the oxidative pathway. The research is potentially transformative because it opens up new approaches for metabolic engineering of microorganisms to convert crude glycerol byproducts from biorefinery operations to liquid transportation fuels. Broader Impacts This research project provides opportunities to educate students and other educators about alternative energy, renewable resources, and biorefining. The education plan will develop the technical and laboratory expertise for graduate and undergraduate students to prepare them for careers in the biofuels industry, which is currently experiencing substantial growth. Various outreach activities are planned, including the development of a seminars and demonstrations to educate K-12 students, teachers, and community members about biofuels production and utilization. Education efforts will also focus on the recruitment of students from underrepresented groups through activities that will target the inclusion of these students. These educational and outreach activities will stimulate broad interest in science and engineering, and inspire K-12 students to pursue higher education and careers in engineering and energy industries. The proposed outreach activities also include a web based wiki site and summer exchange program that will facilitate collaboration among graduate and undergraduate students in the two research groups.