Browsing by Autor "Gen Larsson"
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Item type: Item , Comparison of engineered Escherichia coli AF1000 and BL21 strains for (R)-3-hydroxybutyrate production in fed-batch cultivation(Springer Science+Business Media, 2019) Mariel Pérez-Zabaleta; Mónica Guevara-Martínez; Martin Gustavsson; Jorge Quillaguamán; Gen Larsson; Antonius J. A. van MarisItem type: Item , Cultivation strategies for production of (R)-3-hydroxybutyric acid from simultaneous consumption of glucose, xylose and arabinose by Escherichia coli(BioMed Central, 2015) Johan Jarmander; Jaroslav Belotserkovsky; Gustav Sjöberg; Mónica Guevara-Martínez; Mariel Pérez-Zabaleta; Jorge Quillaguamán; Gen LarssonItem type: Item , Improvements of poly(3-hydroxybutyrate) production in an air-lift reactor using simple production media(Springer Science+Business Media, 2020) Nancy Ortiz-Veizán; Jeanett Daga-Quisbert; Mariel Pérez-Zabaleta; Mónica Guevara-Martínez; Gen Larsson; Jorge QuillaguamánItem type: Item , Increasing the production of (R)-3-hydroxybutyrate in recombinant Escherichia coli by improved cofactor supply(BioMed Central, 2016) Mariel Pérez-Zabaleta; Gustav Sjöberg; Mónica Guevara-Martínez; Johan Jarmander; Martin Gustavsson; Jorge Quillaguamán; Gen LarssonIn a recently discovered microorganism, Halomonas boliviensis, polyhydroxybutyrate production was extensive and in contrast to other PHB producers, contained a set of alleles for the enzymes of this pathway. Also the monomer, (R)-3-hydroxybutyrate (3HB), possesses features that are interesting for commercial production, in particular the synthesis of fine chemicals with chiral specificity. Production with a halophilic organism is however not without serious drawbacks, wherefore it was desirable to introduce the 3HB pathway into Escherichia coli. The production of 3HB is a two-step process where the acetoacetyl-CoA reductase was shown to accept both NADH and NADPH, but where the V max for the latter was eight times higher. It was hypothesized that NADPH could be limiting production due to less abundance than NADH, and two strategies were employed to increase the availability; (1) glutamate was chosen as nitrogen source to minimize the NADPH consumption associated with ammonium salts and (2) glucose-6-phosphate dehydrogenase was overexpressed to improve NADPH production from the pentose phosphate pathway. Supplementation of glutamate during batch cultivation gave the highest specific productivity (q3HB = 0.12 g g−1 h−1), while nitrogen depletion/zwf overexpression gave the highest yield (Y3HB/CDW = 0.53 g g−1) and a 3HB concentration of 1 g L−1, which was 50 % higher than the reference. A nitrogen-limited fedbatch process gave a concentration of 12.7 g L−1 and a productivity of 0.42 g L−1 h−1, which is comparable to maximum values found in recombinant E. coli. Increased NADPH supply is a valuable tool to increase recombinant 3HB production in E. coli, and the inherent hydrolysis of CoA leads to a natural export of the product to the medium. Acetic acid production is still the dominating by-product and this needs attention in the future to increase the volumetric productivity further.Item type: Item , Production of 3-hydroxybutyrate by E. coli: Application of Nitrogen and Phosphorous limitation to steer fluxes to product formation(Elsevier BV, 2014) M.V Manzo Guevara; Johan Jarmander; Mariel Pérez-Zabaleta; Jorge Quillaguamán; Gen LarssonItem type: Item , Production of 3-hydroxybutyrate from waste biomass by metabolically engineered Escherichia coli(Elsevier BV, 2014) Johan Jarmander; Mónica Guevara; Mariel Perez Zabaleta; Gustav Sjöberg; Jaroslav Belotserkovsky; Jorge Quillaguamán; Gen LarssonItem type: Item , The role of the acyl-CoA thioesterase “YciA” in the production of (R)-3-hydroxybutyrate by recombinant Escherichia coli(Springer Science+Business Media, 2019) Mónica Guevara-Martínez; Mariel Pérez-Zabaleta; Martin Gustavsson; Jorge Quillaguamán; Gen Larsson; Antonius J. A. van Maris