| 61. |
- Nielsen, Jens B, 1962
(författare)
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Engineering yeast metabolism for production of fuels and chemicals
- 2016
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Ingår i: New Biotechnology. - : Elsevier BV. - 1876-4347 .- 1871-6784. ; 33:Supplement: S Meeting Abstract: PL3, s. S66-S66
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Metabolic engineering relies on the Design-Build-Test cycle. This cycle includes technologies like mathematical modeling of metabolism, genome editing and advanced tools for phenotypic characterization. In recent years there have been advances in several of these technologies, which has enabled faster development of metabolically engineered strains that can be used for production of fuels and chemicals.The yeast Saccharomyces cerevisiae is widely used for production of fuels, chemicals, pharmaceuticals and materials. Through metabolic engineering of this yeast a number of novel industrial processes have been developed over the last 10 years. Besides its wide industrial use, S. cerevisiae also serves as an eukaryal model organism, and many systems biology tools have therefore been developed for this organism. These tools can be used for detailed phenotypic characterization as well as for metabolic design.In this lecture it will be demonstrated how the Design-Build-Test cycle of metabolic engineering has allowed for development of yeast cell factories for production of a range of different fuels and chemicals. Some examples of different technologies will be presented together with examples of metabolic engineering designs, in particular for development of platform strains that can be used for production of a fatty acid derived products, e.g. fatty alcohols and alkanes. It will be argued that with advancement in genome-editing technologies and novel methods for rapid phenotypic screening, advancement in the field is hampered by our design abilities, i.e. to predict genotype–phenotype connections. For this genome-scale metabolic modeling is a strong technology, and in the presentation recent advancements in mathematical modeling for cell factory design will be presented. Finally, the presentation will also demonstrate how the Design-Build-Test cycle can be expanded to incorporate adaptive laboratory evolution to identify targets for engineering complex traits, such as improved tolerance to toxic metabolites like elevated temperatures or low pH.
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| 62. |
- Novak, Ondrej, et al.
(författare)
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Extra- and intracellular distribution of cytokinins in the leaves of monocots and dicots
- 2016
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 33, s. 735-742
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Tidskriftsartikel (refereegranskat)abstract
- The plant hormones cytokinins are a convenient target of genetic manipulations that bring benefits in biotechnological applications. The present work demonstrates the importance of the subcellular compartmentalization of cytokinins on the model dicot plant Arabidopsis thaliana and monocot crop Hordeum vulgare. The method of protoplast and vacuole isolation combined with precise cytokinin analysis and recovery assay of a vacuolar marker protein were used to quantify the contents of individual cytokinin forms in the leaf extracellular space, cell interior and vacuole. The data obtained for wild type plants and in each case a specific mutant line allow comparing the effect of genetic manipulations on the hormone distribution and homeostatic balance of cytokinins in the modified plants.
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| 63. |
- Nyman, Jonas, et al.
(författare)
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Pellet formation of zygomycetes and immobilization of yeast
- 2013
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Ingår i: New Biotechnology. - : Elsevier BV. - 1871-6784 .- 1876-4347. ; 30:5, s. 516-522
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Tidskriftsartikel (refereegranskat)abstract
- Pelleted growth provides many advantages for filamentous fungi, including decreased broth viscosity, improved aeration, stirring, and heat transfer. Thus, the factors influencing the probability of pellet formation of Rhizopus sp. in a defined medium was investigated using a multifactorial experimental design. Temperature, agitation intensity, Ca2+-concentration, pH, and solid cellulose particles, each had a significant effect on pelletization. Tween 80, spore concentration, and liquid volume were not found to have a significant effect. All of the effects were additive; no interactions were significant. The results were used to create a simple defined medium inducing pelletization, which was used for immobilization of a flocculating strain of Saccharomyces cerevisiae in the zygomycetes pellets. A flor-forming S. cerevisiae strain was also immobilized, while a non-flocculating strain colonized the pellets but was not immobilized. No adverse effects were detected as a result of the close proximity between the filamentous fungus and the yeast, which potentially allows for co-fermentation with S. cerevisiae immobilized in pellets of zygomycetes
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| 64. |
- Pedersen, Anders, 1976, et al.
(författare)
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Rational improvement of cell-free protein synthesis.
- 2011
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Ingår i: New Biotechnology. - : Elsevier BV. - 1876-4347 .- 1871-6784. ; 28:3, s. 218-224
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Tidskriftsartikel (refereegranskat)abstract
- Experimental design principles were applied on cell-free protein synthesis to optimize performance with regard to the expression yield and the incorporation efficiency of amino acid precursors. A versatile screening platform based on batch-mode cell-free expression and central composite design was used. The performance of different extracts (S12 and S30), the concentration dependence of key components and the effect of different additives were investigated. We find that the initial expression yield can be enhanced twofold to threefold in this manner. The improved conditions comprise a modified S12 extract, optimized concentrations of creatine phosphate and key amino acids, as well as introduction of ketoacid additives. Our results show that current cell-free expression technology is far from optimal and that higher yields and increased utilization of the provided precursors are attainable with further optimization.
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| 65. |
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| 66. |
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| 67. |
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| 68. |
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| 69. |
- Robinson, Kathryn M., 1975-, et al.
(författare)
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Variation in non-target traits in genetically modified hybrid aspens does not exceed natural variation
- 2021
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Ingår i: New Biotechnology. - : Elsevier. - 1871-6784 .- 1876-4347. ; 64, s. 27-36
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Tidskriftsartikel (refereegranskat)abstract
- Genetically modified hybrid aspens (Populus tremula L. x P. tremuloides Michx.), selected for increased growth under controlled conditions, have been grown in highly replicated field trials to evaluate how the target trait (growth) translated to natural conditions. Moreover, the variation was compared among genotypes of ecologically important non-target traits: number of shoots, bud set, pathogen infection, amount of insect herbivory, composition of the insect herbivore community and flower bud induction. This variation was compared with the variation in a population of randomly selected natural accessions of P. tremula grown in common garden trials, to estimate how the “unintended variation” present in transgenic trees, which in the future may be commercialized, compares with natural variation. The natural variation in the traits was found to be typically significantly greater. The data suggest that when authorities evaluate the potential risks associated with a field experiment or commercial introduction of transgenic trees, risk evaluation should focus on target traits and that unintentional variation in non-target traits is of less concern.
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| 70. |
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