Construction and\nOptimization of Engineered Saccharomyces cerevisiae for <i>De Novo</i> Synthesis of Phloretin and Its Derivatives

Phloretin and its derivatives are dihydrochalcone compounds\nwith\ndiverse pharmacological properties and biological activities, offering\nsignificant potential for applications in the food and pharmaceutical\nindustries. Due to their structural similarity to flavonoids, their\nextraction and isolation were highly challenging. Although the biosynthesis\nof phloretin via three distinct pathways has been reported, a systematic\ncomparison within the same host has yet to be conducted. In this study,\nwe employed rational design and synthetic biology approaches to engineer Saccharomyces cerevisiae for <i>de novo</i> synthesis of phloretin and its derivatives. We constructed and evaluated\nthree biosynthetic pathways for phloretin in S. cerevisiae, demonstrating that effective phloretin synthesis is achievable\nonly via the <i>p</i>-coumaryl-CoA pathway. Additionally,\nby optimizing enzyme screening, strain engineering, and coordinating\nheterologous pathways with endogenous metabolism, we achieved the\nhighest reported <i>de novo</i> titer of 287.2 mg/L for\nphloretin, 184.6 mg/L for phlorizin, 103.1 mg/L for trilobatin, and\n164.5 mg/L for nothofagin and the first-time synthesis of 4-methylphloretin\nand hesperetin dihydrochalcone. This study was committed to addressing\nthe growing demand for dihydrochalcones while laying the foundation\nfor the biosynthesis of more complex derivatives.