Engineering a growth-phase-dependent biosynthetic pathway for carotenoid production in Saccharomyces cerevisiae.

Metabolic engineering is usually focused on static control of microbial cell factories to efficient production of interested chemicals, though heterologous pathways compete with endogenous metabolism. However, products like carotenoids may cause metabolic burden on engineering strains, thus limiting product yields and influencing strain growth. Herein, a growth-phase-dependent regulation was developed to settle this matter, and its efficiency was verified using the heterogenous biosynthesis of lycopene in Saccharomyces cerevisiae as an example. Through growth-phase-dependent control of the lycopene biosynthetic pathway, limited step in MVA pathway, and competitive squalene pathway, production yield was increased by approximately 973-fold (from 0.034- to 33.1-mg/g CDW) and 1.48 g/L of production was obtained by one-stage fermentation in a 5-L bioreactor. Our study not only introduces an economically approach to the production of carotenoids, but also provides an example of dynamic regulation of biosynthetic pathways for metabolic engineering.