Metabolic engineering of Escherichia coli for 1-butanol and 1-propanol production via the keto-acid pathways.
Production of higher alcohols via the keto-acid intermediates found in microorganism's native amino-acid pathways has recently shown promising results. In this work, an Escherichia coli strain that produces 1-butanol and 1-propanol from glucose was constructed. The strain first converts glucose to 2-ketobutyrate, a common keto-acid intermediate for isoleucine biosynthesis. Then, 2-ketobutyrate is converted to 1-propanol through reactions catalyzed by the heterologous decarboxylase and dehydrogenase, or to 1-butanol via the chemistry involved in the synthesis of the unnatural amino acid norvaline. We systematically improved the synthesis of 1-propanol and 1-butanol through deregulation of amino-acid biosynthesis and elimination of competing pathways. The final strain demonstrated a production titer of 2 g/L with nearly 1:1 ratio of butanol and propanol.
Shen
C R
CR
Department of Chemical and Biomolecular Engineering, University of California, 5531 Boelter Hall, Los Angeles, CA 90095, USA.
Liao
J C
JC
D020001:1-Butanol / Q000378:metabolism*; D000433:1-Propanol / Q000378:metabolism*; D001674:Bioelectric Energy Sources; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000502:physiology*; D024861:Genetic Enhancement / Q000379:methods*; D005947:Glucose / Q000378:metabolism*; D007651:Keto Acids / Q000378:metabolism*; D015202:Protein Engineering / Q000379:methods; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
D029968:Escherichia coli Proteins; D007651:Keto Acids; D011994:Recombinant Proteins; D020001:1-Butanol; D000433:1-Propanol; D005947:Glucose