Sustainable Production of Shinorine from Agricultural Wastes Using Engineered <i>Saccharomyces cerevisiae</i> Expressing Novel <scp>d</scp>-Alanine-<scp>d</scp>-alanine Ligase from <i>Pseudonocardia pini</i>

Shinorine, a compound known for its protective properties against UV radiation, is widely used in cosmetics and pharmaceuticals. Despite the construction of various recombinant <i>Saccharomyces cerevisiae</i> strains for shinorine production, achieving industrial-scale yields remains a challenge. In this study, genes encoding enzymes (DDGS, O-MT, and ATP-grasp enzyme) from <i>Actinosynnema mirum</i> were introduced into <i>S. cerevisiae</i> DXdT to enable the heterologous conversion of sedoheptulose 7-phosphate to mycosporine-glycine─the direct biosynthetic precursor of shinorine. Subsequently, a novel d-alanine-d-alanine ligase from <i>Pseudonocardia pini</i> was introduced to produce shinorine. The engineered strain (DXdT-MG-mi89-PP.ddl) produced 267.9 mg/L shinorine with a 48.6 mg/g dry cell weight (DCW) content in a medium supplemented with lignocellulosic hydrolysate derived from rice straw. Notably, the recombinant strain produced 1.7 g/L shinorine with a 79.1 mg/g DCW content from a corn steep liquor medium with a mixture of glucose and xylose. These results support the idea that sustainable shinorine production from agricultural wastes holds significant promise for industrial applications.