Metabolic Engineering of Saccharomyces cerevisiae for Flavonoid Synthesis from Acetate

Acetate is a sustainable C2 feedstock derived from CO2 electroreduction, but its conversion to complex natural products is constrained by impaired cell growth and poor metabolic compatibility. Adaptive laboratory evolution generated an evolved Saccharomyces cerevisiae strain capable of producing 536.32 mg/L of p-coumaric acid from 15 g/L acetate as the sole carbon source. Genome- and transcriptome-level analyses subsequently revealed genetic factors associated with an enhanced acetate utilization. To evaluate acetate-supported flavonoid biosynthesis, a downstream flavonoid pathway was constructed in the parental chassis, yielding 19.55 mg/L of phloretin from acetate. Co-overexpression of EFG1 and ACS1, followed by fermentation optimization, increased the phloretin titer to 35.71 mg/L, reaching 78.71% of the glucose-based level. This work establishes S. cerevisiae as a viable platform for converting renewable C2 feedstocks into complex flavonoids and provides a practical strategy for the low-carbon bioproduction of high-value natural products.