P68: Multi-scale engineering of heterologous polyketide and isoprenoid natural products in Escherichia coli

Natural products are compounds isolated from natural terrestrial and aquatic environments. Many of these natural products are produced by exotic organisms and plants only found in certain areas of the world, therefore creating a limited supply and high production costs. Heterologous biosynthesis has emerged as an option to reconstitute natural product metabolic pathways in an industrially amenable host system. However, most initial efforts have resulted in production titers lower than the native host, resulting in the need for the application of metabolic engineering technologies.

In this study, a multi-scale approach was used to improve the production titers of two classes of heterologous natural products in Escherichia coli: the polyketide 6-deoxyerythronolide B (6-dEB; complex precursor to the antibiotic compound erythromycin) and the diterpenoid taxadiene (complex precursor to paclitaxel). These studies included model-driven analysis of E. coli metabolism to identify knockout candidates that are predicted to improve production, native and heterologous gene over-expression to improve the uptake and utilization efficiency of exogeniously fed substrates, the development of a novel computational algorithm utilizing elementary mode analysis and a genetic algorithm and its application towards improving biosynthesis, and process and cellular engineering strategies to improve both volumetric and specific productivities.