Compositions and methods for rapid and dynamic flux control using synthetic metabolic valves

A bioprocess for production of an isopreniod product from a genetically modified microorganism, the bioprocess comprising:

• providing a genetically modified microorganism that may express a heterologous enzyme of an isoprenoid product production pathway and also comprises a synthetic metabolic valve,
• wherein the synthetic metabolic valve characterized by both:
• (i) controlled transcriptional gene silencing of a gene encoding a first enzyme, and (ii) controlled proteolysis of a second enzyme;
• in a first stage, growing the genetically modified microorganism in a media;
• and
• in a second stage, reducing the genetically modified microorganism growth of the first stage and expressing the heterologous enzyme of the isoprenoid product production pathway, thereby producing the isoprenoid product,
• wherein, a transition from the first stage to the second stage is at least partially controlled by depletion of a level of a limiting nutrient from the media and, as the limiting nutrient is depleted from the media, growth of the genetically modified microorganism is stopped, and the transition comprising silencing the gene of the first enzyme and proteolysis the second enzyme,
• wherein at least one of the first enzymes is selected from the group consisting of:
• enoyl-ACP reductase (fabI), citrate synthase (OA), soluble transhydrogenase (udhA), glucose-6-phosphate-1-dehydrogenase (DO, or lipoamide dehydrogenase (lpd), and combinations thereof;
• and
• wherein at least one of the second enzymes is selected from the group consisting of:
• enoyl-ACP reductase (fabI), citrate synthase (OA), soluble transhydrogenase (udhA), glucose-6-phosphate-1-dehydrogenase (DO, or lipoamide dehydrogenase (lpd), and combinations thereof.