Toward sustainable food preservatives: high-level production of sorbic acid in engineered Saccharomyces cerevisiae

Sorbic acid (SA) and its salts are among the world's most widely used and safest food preservatives, yet their industrial production still relies on fossil fuel-derived feedstocks via chemical synthesis. Here, we report bioproduction of SA through microbial fermentation by decoding its biosynthetic pathway and metabolic engineering of Saccharomyces cerevisiae as a chassis. Here, we identify SA and its amide derivative sorbamide (SN) from Myrothecium sp. FJNU6, representing identification of SA from a microbial source. Genome sequencing and heterologous expression reveal the SA/SN biosynthetic gene cluster, comprising a highly reducing polyketide synthase (SoaA), a hydrolase (SoaB), and an amidotransferase (SoaC). To enable sustainable overproduction, we reconstitute and optimize the SoaA-SoaB pathway in S. cerevisiae through multilevel engineering, including dynamic promoter control, acetyl-CoA/malonyl-CoA pathway enhancement, peroxisomal compartmentalization, and two-stage fed-batch fermentation. These strategies collectively enable a production titer of 1.84 g/L SA in a 50 L bioreactor. This study uncovers a microbial biosynthetic pathway for SA/SN and establishes a microbial platform for SA production, providing a foundation for developing sustainable alternatives to fossil-based manufacturing.