Establishing genetically stable Escherichia coli for effective myo-inositol production

myo-Inositol (MI), also known as vitamin B8, participates in various physiological processes such as blood glucose regulation, lipid metabolism, and cellular aging. Escherichia coli has emerged as a promising microbial chassis for MI biosynthesis. However, its industrial application is often limited by metabolic burden and genetic instability in high-expression systems. In this study, a combination of inducible and constitutive promoters was employed to express the pathway genes INO1 and suhB, resulting in the construction of a multi-copy integration strain. Subsequently, metabolic engineering strategies aimed at improving carbon transport efficiency and optimizing nitrogen source supply further shortened the fermentation period. Under optimized fed-batch fermentation conditions, the final engineered strain achieved a high MI titer of 191.72 g/L, a carbon yield of 0.70 g/g, and a productivity of 1.59 g/L/h. This study presents an effective strategy for developing stable and efficient microbial cell factories suitable for the industrial production of high-value biochemicals.