Tandem Repeat Gene Strategy for High-Yield Production and Functional Evaluation of Bioactive Wheat Oligopeptides

Bioactive wheat peptides are promising functional ingredients, yet their industrial production remains constrained by low yields, product heterogeneity, and poor scalability associated with conventional enzymatic hydrolysis and chemical synthesis. Here, we report a tandem-repeat gene strategy for the scalable biosynthesis of the representative wheat peptide YDW (Tyr-Asp-Trp-Pro-Gly-Gly-Arg-Asn). By integrating codon optimization with engineered pepsin-cleavable linkers, high-molecular-weight precursor proteins were efficiently expressed in Escherichia coli and subsequently converted into homogeneous target peptides through site-specific enzymatic processing. Systematic evaluation of repeat architectures identified the 24-repeat construct as optimal, reflecting a balance between gene length, mRNA stability, and translational burden. This system achieved peptide yields of up to 5 g/L in a 700 L fermentation process, demonstrating strong scalability. The resulting peptides exhibited high purity and correct molecular weight, as confirmed by HPLC and LC-MS/MS analyses. Functional assays further showed that YDW significantly enhanced cellular collagen I expression by over 240% relative to controls, supporting its potential in anti-photoaging and tissue repair applications. This work establishes a generalizable and scalable platform for the biomanufacturing of cereal-derived bioactive peptides, providing a practical alternative to conventional methods and enabling future studies on peptide structure-function relationships and industrial applications.