From β-Carotene to Retinoids: A Review of Microbial Production of Vitamin A.

Vitamin A (retinoids) is crucial for human health, with significant demand across the food, pharmaceutical, and animal feed industries. Currently, the market primarily relies on chemical synthesis and natural extraction methods, which face challenges such as low synthesis efficiency and complex extraction processes. Advances in synthetic biology have enabled vitamin A biosynthesis using microbial cell factories, offering a promising and sustainable solution to meet the increasing market demands. This review introduces the key enzymes involved in the biosynthesis of vitamin A from β-carotene, evaluates achievements in vitamin A production using various microbial hosts, and summarizes strategies for optimizing vitamin A biosynthesis. Additionally, we outline the remaining challenges and propose future directions for the biotechnological production of vitamin A.