Elimination of D-lactate synthesis increases poly(3-hydroxybutyrate) and ethanol synthesis from glycerol and affects cofactor distribution in recombinant Escherichia coli
The effect of eliminating D-lactate synthesis in poly(3-hydroxybutyrate) (PHB)-accumulating recombinant Escherichia coli (K24K) was analyzed using glycerol as a substrate. K24KL, an ldhA derivative, produced more biomass and had altered carbon partitioning among the metabolic products, probably due...
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| Autores principales: | , , , , |
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| Formato: | Artículo publishedVersion |
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2010
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00992240_v76_n22_p7400_Nikel https://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=artiaex&d=paper_00992240_v76_n22_p7400_Nikel_oai |
| Aporte de: |
| Sumario: | The effect of eliminating D-lactate synthesis in poly(3-hydroxybutyrate) (PHB)-accumulating recombinant Escherichia coli (K24K) was analyzed using glycerol as a substrate. K24KL, an ldhA derivative, produced more biomass and had altered carbon partitioning among the metabolic products, probably due to the increased availability of carbon precursors and reducing power. This resulted in a significant increase of PHB and ethanol synthesis and a decrease in acetate production. Cofactor measurements revealed that cultures of K24K and K24KL had a high intracellular NADPH content and that the NADPH/NADP+ ratio was higher than the NADH/NAD+ ratio. The ldhA mutation affected cofactor distribution, resulting in a more reduced intracellular state, mainly due to a further increase in NADPH/NADP+. In 60-h fed-batch cultures, K24KL reached 41.9 g · liter-1 biomass and accumulated PHB up to 63% ± 1% (wt/wt), with a PHB yield on glycerol of 0.41 ± 0.03 g · g-1, the highest reported using this substrate. © 2010, American Society for Microbiology. |
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