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Metabolic engineeri...
Metabolic engineering and cultivation strategies for recombinant production of (R)-3-hydroxybutyrate
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- Perez-Zabaleta, Mariel, 1987- (author)
- KTH,Skolan för kemi, bioteknologi och hälsa (CBH),Industrial Biotechnology
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- Larsson, Gen, Professor (thesis advisor)
- KTH,Skolan för kemi, bioteknologi och hälsa (CBH),Centrum för Bioprocessteknik, CBioPT,Bioteknologi
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- van Maris, Antonius J. A., Professor, 1976- (thesis advisor)
- KTH,Skolan för kemi, bioteknologi och hälsa (CBH)
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- Mattanovich, Diethard, Professor (opponent)
- University of Natural Resources and Life Sciences Vienna
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(creator_code:org_t)
- ISBN 9789178732166
- KTH Royal Institute of Technology, 2019
- English 106 s.
- Related links:
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https://kth.diva-por... (primary) (Raw object)
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https://urn.kb.se/re...
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Abstract
Subject headings
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- Metabolic engineering and process engineering are two powerful disciplines to design and improve microbial processes for sustainable production of an extensive number of compounds ranging from chemicals to pharmaceuticals. The aim of this thesis was to synergistically combine these two disciplines to improve the production of a model chemical called (R)-3-hydroxybutyrate (3HB), which is a medium-value product with a stereocenter and two functional groups. These features make 3HB an interesting building block, especially for the pharmaceutical industry. Recombinant production of 3HB was achieved by expression of two enzymes from Halomonas boliviensis in the model microorganism Escherichia coli, which is a microbial cell factory with proven track record and abundant knowledge on its genome, metabolism and physiology.Investigations on cultivation strategies demonstrated that nitrogen-depleted conditions had the biggest impact on 3HB yields, while nitrogen-limited cultivations predominantly increased 3HB titers and volumetric productivities. To further increase 3HB production, metabolic engineering strategies were investigated to decrease byproduct formation, enhance NADPH availability and improve the overall 3HB-pathway activity. Overexpression of glucose-6-phosphate dehydrogenase (zwf) increased cofactor availability and together with the overexpression of acyl-CoA thioesterase YciA resulted in a 2.7-fold increase of the final 3HB concentration, 52% of the theoretical product yield and a high specific productivity (0.27 g g-1 h-1). In a parallel strategy, metabolic engineering and process design resulted in an E. coli BL21 strain with the hitherto highest reported volumetric 3HB productivity (1.52 g L-1 h-1) and concentration (16.3 g L-1) using recombinant production. The concepts developed in this thesis can be applied to industrial 3HB production processes, but also advance the knowledge base to benefit design and expansion of the product range of biorefineries.
Keyword
- Escherichia coli
- (R)-3-hydroxybutyrate
- nitrogen limitation
- nitrogen depletion
- lignocellulose
- fed batch
- acetate
- β-ketothiolase
- acetoacetyl-CoA reductase
- Halomonas boliviensis.
- Bioteknologi
- Biotechnology
Publication and Content Type
- vet (subject category)
- dok (subject category)
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