Metabolic Engineering for the Heterologous Biosynthesis of Erythromycin A and Associated Polyketide Products in Escherichia coli.
Zhang, Haoran.
2017-04-18T14:05:42.372Z
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Abstract: The natural product erythromycin is a potent and widely used antibiotic for bacterial infections. In structure, erythromycin consists of one 14-membered polyketide ring, 6-deoxy-erythronolide B (6dEB), and two sugar residues, cladinose and desosamine. Erythromycin is natively produced by a soil-dwelling bacterium Saccharopolyspora erythraea that is fastidious in its growth requirements a... read morend hard to manipulate through genetic and metabolic engineering approaches. In this thesis study, the production of the erythromycin polyketide precursor 6dEB was optimized by engineering the Escherichia coli native metabolic pathways to support biosynthesis of the required substrates. Furthermore, heterologous biosynthesis of the erythromycin sugar groups cladinose and desosamine was achieved to produce the final product erythromycin A in E. coli. The reported titer for erythromycin A was ~10 mg/L. The entire 55kb erythromycin producing gene cluster was then systematically transferred to E. coli to enable the complete heterologous biosynthesis of erythromycin from propionate. Lastly, novel erythromycin associated polyketide analogs were produced by modification of the polyketide and sugar moiety biosynthetic pathways in E. coli. The resulting products contained altered polyketide or sugar groups, as directed by the rationally designed new biosynthetic pathway. Success establishes E. coli as a viable option for the heterologous production of erythromycin A and, more broadly, as a platform for the directed production of erythromycin associated polyketide analogs.
Thesis (Ph.D.)--Tufts University, 2011.
Submitted to the Dept. of Chemical and Biological Engineering.
Advisor: Blaine Pfeifer.
Committee: Andrew Wright, Marcia Osburne, and Kyongbum Lee.
Keyword: Chemical Engineering.read less - ID:
- 5q47s112z
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