Cinnamic acid and p-coumaric acid are metabolized to 4-hydroxybenzoic acid by Yarrowia lipolytica

Yarrowia lipolytica has been explored as a potential production host for flavonoid synthesis due to its high tolerance to aromatic acids and ability to supply malonyl-CoA. However, little is known about its ability to consume the precursors cinnamic and p-coumaric acid. In this study, we demonstrate that Y. lipolytica can consume these precursors through multiple pathways that are partially dependent on the cultivation medium. By monitoring the aromatic acid concentrations over time, we found that cinnamic acid is converted to p-coumaric acid. We identified potential proteins with a trans-cinnamate 4-monooxygenase activity in Y. lipolytica and constructed a collection of 15 knock-out strains to identify the genes responsible for the reaction. We identified YALI1_B28430g as the gene encoding for a protein that converts cinnamic acid to p-coumaric acid (designated as TCM1). By comparing different media compositions we found that complex media components (casamino acids and yeast extract) induce this pathway. Additionally, we discover the conversion of p-coumaric acid to 4-hydroxybenzoic acid. Our findings provide new insight into the metabolic capabilities of Y. lipolytica and hold great potential for the future development of improved strains for flavonoid production.