Engineering aYeast Cell Factory to Sustainably BiosynthesizeParthenolide

The sesquiterpene lactone parthenolide is a promising anticancer drug. Its biosynthesis via a microbial cell factory has been considered as a sustainable alternative to plant extraction. Herein, systematic metabolic engineering approaches, as well as the introduction of a novel noncanonical tricarboxylic acid (TCA) cycle, were employed to enhance the production of the key precursor germacrene A. By identifying two new dehydrogenases and controlling the expression of parthenolide synthase, we further achieved the elimination of byproducts and enhanced parthenolide production. A two-stage fermentation approach and <i>in situ</i> product extraction using macroreticular resin were further applied to relieve the nocuous effect of costunolide and parthenolide on the growth of yeast cell factories, ultimately achieving a titer of 549.7 mg/L for parthenolide and 972.7 mg/L for costunolide in a 10 L fermenter, which represents the highest reported titer obtained by microbial fermentation. The strategies should also contribute to the microbial cell factory-construction for other natural products exhibiting toxicity.