Recent Strategies for the Biosynthesis of Ergothioneine.

Ergothioneine (EGT) is a unique naturally occurring amino acid that is usually biosynthesized by bacteria and fungi. As a food-derived antioxidant and cytoprotectant, it has several physiological benefits and has a wide range of applications in food, medicine, and cosmetics. Traditional production of EGT is mainly through biological extraction or chemical synthesis; however, these methods are inefficient, making large-scale production to meet the growing market demand difficult. Nowadays, the rapid development of synthetic biology has greatly accelerated the research on the EGT production by microbial fermentation. In this paper, the biological characteristics, applications, biosynthesis, separation, and detection methods of EGT were fully reviewed. Furthermore, the approaches and challenges for engineering microbial cells to efficiently synthesize EGT were also discussed. This work provides new ideas and future research potentials in EGT production.