Peter and Ruth Nicholas Postdoctoral Fellow
Ph.D., Molecular Genetics, Baylor College of Medicine, June 2009
B.S., Chemistry, University of Wisconsin-Green Bay, May 2001
Glycerol has become an ideal feedstock for the microbial synthesis of biochemicals due to its high degree of reduction, abundance, and plummeting prices. The Gonzalez Laboratory has previously delineated the pathways for the fermentative use of glycerol by Escherichia coli in minimal salts media under microaerobic conditions. With my project, I have capitalized on such results to engineer E. coli for the production of value-added succinic acid (succinate, C4H6O4) from glycerol that could become a central platform chemical to produce a wide spectrum of products such as: pharmaceuticals, food additives, biodegradable plastics, paints, green solvents, deicers, and fuel additives.
Through rational design, succinate production was greatly elevated by 1) blocking pathways for the competing production of lactate (ΔldhA), ethanol (ΔadhE), and acetate (Δpta), and 2) expressing Lactococcus lactis pyruvate carboxylase in E. coli to sequester CO2 and drive the generation of succinate from pyruvate, circumventing low phosphoenolpyruvate levels. This metabolic engineering strategy coupled cell growth to succinate production because the creation of succinate remained as the primary route of NAD+ regeneration Our succinate biocatalysts demonstrated a maximum productivity of 25.8 mg/L/h (specific productivity 96.7 mg/h/g) and at a yield of 54% (69% g/g) of theoretical maximum.
While this is the first description of metabolically engineering E. coli to produce succinate from glycerol, performances are on par to those achieved in the equivalent synthesis of organic acids from sugars using recombinant E. coli strains.
Peter and Ruth Nicholas Postdoctoral Fellowship, 2011
BCM Molecular and Human Genetics Best Student Paper, 2007
Fellowship to Molecular Genetics of Bacteria and Phage Meeting, Madison, WI, 2007
Graduated Magna Cum Laude, 2001
Robert E. Lee & Associates Scholarship in Chemistry, 2000
UWGB Faculty Science and Mathematics Scholarship, 2000
Nancy A. Sell Memorial Scholarship, 1999
Mason Scholarship, 1996
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