Synergetic Engineering of Multiple Pathways for <i>De Novo</i> (<i>2S</i>)-Naringenin Biosynthesis in <i>Saccharomyces cerevisiae</i>

Abstract

( 2S )-Naringenin is a high-value flavonoid precursor with different biological properties. However, current metabolic engineering strategies do not fully use intracellular carbon sources for the synthesis of ( 2S )-naringenin. Inadequate precursors and the loss of carbon metabolic flux severely limit the microbial heterologous synthesis of ( 2S )-naringenin. In this work, a systems engineering strategy was employed for the high-level production of ( 2S )-naringenin. First, the synthetic pathways of shikimic acid and aromatic amino acids were optimized. Carbon flux was redirected into the ( 2S )-naringenin biosynthetic pathway through the concentrated utilization of aromatic amino acids and the introduction of a heterologous phosphoketolase pathway. Then, byproduct accumulation was reduced by replacing endogenous enoyl-CoA reductase with a plant homologous enzyme. Subsequently, overexpression of the endogenous malonyl-CoA synthesis pathway genes and introduction of the acetaldehyde dehydrogenase (acylating) pathway promote ( 2S )-naringenin production. The regulation of the subcellular organelle carbon trafficking system resulted in the production of ( 2S )-naringenin reaching 986.2 mg/L in shake flasks. Finally, the ( 2S )-naringenin titer reached 3420.6 mg/L after fermentation in a 5 L bioreactor, the highest titer ever reported. This study not only provides a possibility for the efficient bioproduction of flavonoids but also provides ideas for the biosynthesis of natural products through the centralized utilization of intracellular carbon sources.

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