Efficient Synthesis of Food-Derived Antioxidant <scp>l</scp>-Ergothioneine by Engineered <i>Corynebacterium glutamicum</i>

Abstract

l-Ergothioneine (EGT) is a strong antioxidant used in industry, and it is commonly extracted from mushrooms; however, its production is limited. As an alternative, we developed metabolically engineered <i>Corynebacterium glutamicum</i> with reinforced sulfur assimilation and pentose phosphate pathways, which led to the accumulation of 45.0 and 63.2 mg/L EGT, respectively. Additionally, the overexpression of <i>cysEKR</i> resulted in further promoted EGT production in ET4 (66.5 mg/L) and ET7 (85.0 mg/L). Based on this result, we developed the strain ET11, in which all sulfur assimilatory, PP, and l-cysteine synthetic pathways were reinforced, and it synthesized 264.4 mg/L EGT. This study presents the first strategy for EGT synthesis that does not require precursor addition in <i>C. glutamicum</i>, and the production time was shortened. In addition, the synthesized EGT showed high radical scavenging activity (70.7%), thus confirming its antioxidant function. Consequently, this study showed the possibility of EGT commercialization by overcoming the limitations of industrial processes.