Metabolic engineering of Saccharomyces cerevisiae for de novo biosynthesis of isoorientin
TL;DR
An engineered yeast platform for isoorientin synthesis is established by implementing a strategy for P450 optimization, providing a framework for microbial production of glycosylated natural products.
Abstract
The flavonoid glycoside isoorientin has demonstrated antitumor, cardioprotective, and gut-protective activities, as well as potential applications as a natural biopesticide and antimicrobial agent. However, large-scale production and industrial development of isoorientin are limited by its low abundance in plants. In this study, we used metabolic engineering to construct an isoorientin-producing budding yeast (Saccharomyces cerevisiae) cell factory. To enhance production of the intermediate naringenin, we overexpressed key genes in the shikimic acid and naringenin pathways, reinforced the cytosolic malonyl-CoA supply, and redirected subcellular acetyl-CoA flux. After screening enzymes from diverse sources, we identified an optimized enzyme combination for luteolin biosynthesis from naringenin: CYP93G1 (from Oryza sativa L.), ATR1 (from Arabidopsis thaliana [L.] Heynh.), and SbFBH2 (from Scutellaria baicalensis Georgi)-ATR2 (from A. thaliana). To address cytochrome P450 (P450)-related bottlenecks, we optimized gene dosage and engineered the P450 microenvironment by increasing the supply of NADPH and heme and expanding the size of the endoplasmic reticulum. Finally, introducing a flavone 6-C-glycosyltransferase, coupled with optimizing the culture medium and enhancing the UDP-glucose supply, enabled de novo isoorientin biosynthesis. Therefore, we established an engineered yeast platform for isoorientin synthesis by implementing a strategy for P450 optimization, providing a framework for microbial production of glycosylated natural products.