Microbial Production of N-Acetylneuraminic Acid Using Metabolically Engineered Escherichia coli and Bacillus subtilis: Advances and Perspectives

N-Acetylneuraminic acid (Neu5Ac), the predominant form of sialic acids (Sias), is exten- sively utilized in the food, pharmaceutical, and cosmetic industries. Microbial fermentation serves as a critical production method for its economical, eco-friendly, and scalable pro- duction. Escherichia coli and Bacillus subtilis, as primary industrial workhorses for Neu5Ac production, have been extensively investigated owing to their well-characterized genetic frameworks and mature molecular toolkits....