Browsing by Author "Wang, Yipeng"

Now showing 1 - 3 of 3
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    Cofactor engineering for advancing chemical biotechnology
    (Elsevier, 2013) Wang, Yipeng; San, Ka-Yiu; Bennett, George N.; Bioengineering; Biosciences; Chemical and Biomolecular Engineering
    Cofactors provide redox carriers for biosynthetic reactions, catabolic reactions and act as important agents in transfer of energy for the cell. Recent advances in manipulating cofactors include culture conditions or additive alterations, genetic modification of host pathways for increased availability of desired cofactor, changes in enzyme cofactor specificity, and introduction of novel redox partners to form effective circuits for biochemical processes and biocatalysts. Genetic strategies to employ ferredoxin, NADH and NADPH most effectively in natural or novel pathways have improved yield and efficiency of large-scale processes for fuels and chemicals and have been demonstrated with a variety of microbial organisms.
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    Improvement of NADPH bioavailability in Escherichia coli through the use of phosphofructokinase deficient strains
    (Springer-Verlag, 2013) Wang, Yipeng; San, Ka-Yiu; Bennett, George N.; Bioengineering; Biosciences; Chemical and Biomolecular Engineering
    NADPH-dependent reactions play important roles in production of industrially valuable compounds. In this study, we used phosphofructokinase (PFK)-deficient strains to direct fructose-6-phosphate to be oxidized through the pentose phosphate pathway (PPP) to increase NADPH generation. pfkA or pfkB single deletion and double-deletion strains were tested for their ability to produce lycopene. Since lycopene biosynthesis requires many NADPH, levels of lycopene were compared in a set of isogenic strains, with the pfkA single deletion strain showing the highest lycopene yield. Using another NADPH-requiring process, a one-step reduction reaction of 2-chloroacrylate to 2-chloropropionic acid by 2- haloacrylate reductase, the pfkA pfkB double-deletion strain showed the highest yield of 2-chloropropionic acid product. The combined effect of glucose-6-phosphate dehydrogenase overexpression or lactate dehydrogenase deletion with PFK deficiency on NADPH bioavailability was also studied. The results indicated that the flux distribution of fructose-6- phosphate between glycolysis and the pentose phosphate pathway determines the amount of NAPDH available for reductive biosynthesis.
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    Native NAD-dependent GAPDH replaced with NADP-dependent GAPDH plus NADK
    (2014-04-29) San, Ka-Yiu; Bennett, George N.; Wang, Yipeng; Rice University; United States Patent and Trademark Office
    This invention is metabolically engineer bacterial strains that provide increased intracellular NADPH availability for the purpose of increasing the yield and productivity of NADPH-dependent compounds. In the invention, native NAD-dependent GAPDH is replaced with NADP-dependent GAPDH plus overexpressed NADK. Uses for the bacteria are also provided.