Metabolic engineering of Saccharomyces cerevisiae for the biosynthesis of indole-derived compounds

Indole-3-acetonitrile (IAN) and its derivatives-indole-3-carboxaldehyde (I3A), indole-3-carboxylic acid (I3CA), and 3,3'-diindolylmethane (DIM)-are high-value indole-derived compounds widely used in the chemical, pharmaceutical, and nutraceutical industries. However, their de novo microbial production has not yet been achieved. In this study, we constructed a Saccharomyces cerevisiae platform for the de novo biosynthesis of IAN and its downstream derivatives. Reconstruction and optimization of the native plant pathway enabled production of 189.02 mg/l IAN from glucose, and the pathway was subsequently extended to I3A and I3CA, reaching titers of 65.85 and 13.95 mg/l, respectively. Furthermore, an artificial biosynthetic route to DIM was constructed by identifying a previously uncharacterized I3A reductase, enabling the microbial production of DIM from glucose. This work establishes a microbial platform for de novo biosynthesis of IAN and its derivatives and demonstrates a general strategy for producing natural and nonnatural indole derivatives.