Orthogonal Engineering of Biosynthetic Pathway for Efficient Production of Limonene in Saccharomyces cerevisiae

Limonene, a plant-derived natural cyclic monoterpene, is widely used in the pharmaceutical, food, and cosmetics industries. The conventional limonene biosynthetic (CLB) pathway in engineered Saccharomyces cerevisiae consists of heterologous limonene synthase (LS) using endogenous substrate geranyl diphosphate (GPP) and suffers from poor production of limonene. In this study, we report on an orthogonal engineering strategy in S. cerevisiae for improving the production of limonene. We reconstructed the orthogonal limonene biosynthetic (OLB) pathway composed of SlNDPS1 that catalyzes IPP and DMAPP to NPP ( cis-GPP) and plant LS that converts NPP to limonene. We find that the OLB pathway is more efficient for production of limonene than the CLB pathway. When expression of the competing gene ERG20 was chromosomally regulated by the glucose-sensing promoter HXT1, the OLB pathway-harboring strain produced 917.7 mg/L of limonene in fed-batch fermentation, a 6-fold increase of the CLB pathway, representing the highest titer reported to date. Orthogonal engineering exhibits great potential for production of terpenoids in S. cerevisiae.