Engineering the Biosynthesis of Daidzein and Genistein with the Red Oleaginous Yeast Rhodotorula toruloides

Daidzein (DEIN) and genistein (GEIN) are aromatic amino acid (AAAs) derivatives that have various physiological, nutritional, and medical activities. The low abundance in natural sources and structural complexity limit their acquisition through plant extraction and chemical synthesis. The versatile red yeast Rhodotorula toruloides, endowed with critical enzymes for producing AAAs and derivatives, has been engineered to produce DEIN and GEIN. First, the stability of DEIN and GEIN and the selectivity of chalcone synthase were investigated before constructing the biosynthetic pathway for DEIN and GEIN. Second, ATP-citrate lyase was inactivated to downregulate the lipid biosynthesis and redirect the metabolic flux toward DEIN and GEIN production. Then, the biosynthesis of DEIN and GEIN was enhanced by enzyme fusion. Finally, the production of DEIN and GEIN reached 6.92 and 3.55 mg/L, respectively. Herein, the biosynthesis of DEIN and GEIN was achieved for the first time with R. toruloides, which should provide insights into the bioproduction of AAAs-derived compounds.