Enzyme evolution and metabolic engineering for 5-aminolevulinic acid production.

5-Aminolevulinic acid (5-ALA), a nonproteinogenic amino acid, has emerged as a versatile metabolite for applications in health, agriculture, and sustainability. Advances in ALA synthase engineering and metabolic rewiring have enabled scalable biosynthesis. The next frontier should expand beyond production, positioning it as a gateway to future biotechnological applications.