Eichenberger, Michael (2019)
Biosynthesis of plant polyketides in yeast.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
Industrial biotechnology aims to replace production processes based on petrochemicals with more sustainable biological processes based on renewable raw materials. With the rise of metabolic engineering and synthetic biology in the last decades, the range of products attainable by this technology has widened substantially. This thesis explores the potential of Saccharomyces cerevisiae for the production of two commercially interesting compound classes within the plant polyphenols. The first part demonstrates heterologous production of various dihydrochalcones. A side activity of the native ScTsc13, the reduction of p-coumaroyl-CoA to p- dihydrocoumaroyl-CoA, was used for de novo production of phloretin, the first committed dihydrochalcone. By further extension of the pathway from phloretin, by employing decorating enzymes with known specificities for dihydrochalcones, and by exploiting substrate flexibility of enzymes involved in flavonoid biosynthesis, de novo production of the antioxidant molecule nothofagin, the antidiabetic molecule phlorizin, the sweet molecule naringin dihydrochalcone, and 3-hydroxyphloretin was achieved. In the second part, yeast was engineered for de novo production of anthocyanins, molecules that are used in the food and beverage industries as natural colorants. Enzymes from different plant sources were screened and efficient variants were found for most steps of the pathways to the three main anthocyanins. However, as previously shown in vitro and in Escherichia coli, the shunt flavonol production by the anthocyanidin synthase was a major limitation. In the third part, this flavonol by-product formation was eliminated by co- expression of glutathione-S-transferases. These enzymes, previously thought to be involved in vacuolar transport of anthocyanins in plants, were shown to be required for correct product formation by anthocyanidin synthases. By additional co-expression of glycosyltransferases and a malonyltransferase, the pathway was extended to various decorated anthocyanins with a range of different colors. This thesis uncovers and describes important steps towards a sustainable biotechnological process for production of dihydrochalcones and anthocyanins. However, further optimization to increase titers will be required before such processes become commercially viable.
Typ des Eintrags: | Dissertation | ||||
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Erschienen: | 2019 | ||||
Autor(en): | Eichenberger, Michael | ||||
Art des Eintrags: | Erstveröffentlichung | ||||
Titel: | Biosynthesis of plant polyketides in yeast | ||||
Sprache: | Englisch | ||||
Referenten: | Süß, Prof. Dr. Beatrix ; Warzecha, Prof. Dr. Heribert ; Næsby, Dr. Michael | ||||
Publikationsjahr: | 2019 | ||||
Ort: | Darmstadt | ||||
Datum der mündlichen Prüfung: | 26 März 2018 | ||||
URL / URN: | https://tuprints.ulb.tu-darmstadt.de/8574 | ||||
Kurzbeschreibung (Abstract): | Industrial biotechnology aims to replace production processes based on petrochemicals with more sustainable biological processes based on renewable raw materials. With the rise of metabolic engineering and synthetic biology in the last decades, the range of products attainable by this technology has widened substantially. This thesis explores the potential of Saccharomyces cerevisiae for the production of two commercially interesting compound classes within the plant polyphenols. The first part demonstrates heterologous production of various dihydrochalcones. A side activity of the native ScTsc13, the reduction of p-coumaroyl-CoA to p- dihydrocoumaroyl-CoA, was used for de novo production of phloretin, the first committed dihydrochalcone. By further extension of the pathway from phloretin, by employing decorating enzymes with known specificities for dihydrochalcones, and by exploiting substrate flexibility of enzymes involved in flavonoid biosynthesis, de novo production of the antioxidant molecule nothofagin, the antidiabetic molecule phlorizin, the sweet molecule naringin dihydrochalcone, and 3-hydroxyphloretin was achieved. In the second part, yeast was engineered for de novo production of anthocyanins, molecules that are used in the food and beverage industries as natural colorants. Enzymes from different plant sources were screened and efficient variants were found for most steps of the pathways to the three main anthocyanins. However, as previously shown in vitro and in Escherichia coli, the shunt flavonol production by the anthocyanidin synthase was a major limitation. In the third part, this flavonol by-product formation was eliminated by co- expression of glutathione-S-transferases. These enzymes, previously thought to be involved in vacuolar transport of anthocyanins in plants, were shown to be required for correct product formation by anthocyanidin synthases. By additional co-expression of glycosyltransferases and a malonyltransferase, the pathway was extended to various decorated anthocyanins with a range of different colors. This thesis uncovers and describes important steps towards a sustainable biotechnological process for production of dihydrochalcones and anthocyanins. However, further optimization to increase titers will be required before such processes become commercially viable. |
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URN: | urn:nbn:de:tuda-tuprints-85742 | ||||
Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie | ||||
Fachbereich(e)/-gebiet(e): | 10 Fachbereich Biologie 10 Fachbereich Biologie > Synthetic Genetic Circuits (2020 umbenannt in "Synthetic RNA biology") |
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Hinterlegungsdatum: | 07 Apr 2019 19:55 | ||||
Letzte Änderung: | 07 Apr 2019 19:55 | ||||
PPN: | |||||
Referenten: | Süß, Prof. Dr. Beatrix ; Warzecha, Prof. Dr. Heribert ; Næsby, Dr. Michael | ||||
Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 26 März 2018 | ||||
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