1 Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark 2 iLoop, Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark 3 Network Reconstruction in Silico Biology, Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark 4 University of California
Maintaining cofactor balance is a critical function in microorganisms, but often the native cofactor balance does not match the needs of an engineered metabolic flux state. Here, an optimization procedure is utilized to identify optimal cofactor-specificity "swaps" for oxidoreductase enzymes utilizing NAD(H) or NADP(H) in the genome-scale metabolic models of Escherichia coli and Saccharomyces cerevisiae. The theoretical yields of all native carbon-containing molecules are considered, as well as theoretical yields of twelve heterologous production pathways in E. coli. Swapping the cofactor specificity of central metabolic enzymes (especially GAPD and ALCD2x) is shown to increase NADPH production and increase theoretical yields for native products in E. coli and yeast-including l-aspartate, l-lysine, l-isoleucine, l-proline, l-serine, and putrescine-and non-native products in E. coli-including 1,3-propanediol, 3-hydroxybutyrate, 3-hydroxypropanoate, 3-hydroxyvalerate, and styrene. © 2014 International Metabolic Engineering Society.
Metabolic Engineering, 2014, Vol 24, p. 117-128
Cofactor balancing; Constraint-based modeling; Escherichia coli; Metabolic engineering; MILP; Saccharomyces cerevisiae; Theoretical yield; Amino acids; Enzymes; Integer programming; Metabolism; Styrene; Cofactor specificity; Cofactors; Genome-scale metabolic models; Heterologous production; Optimization procedures; Yeast
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