Synergistic utilization of glucose and xylose for the myo-inositol biosynthesis in recombinant Escherichia coli BL21.

Myo-inositol is an active sugar alcohol which has important physiological functions. In this study, an engineered strain that could simultaneously utilize glucose and xylose to produce myo-inositol was constructed, and its fermentation performance was determined. Firstly, the ptsG gene was deleted to make E. coli BL21 capable of utilizing glucose and xylose simultaneously as mixed carbon source. Galp and glk genes were introduced to promote the glucose absorption after ptsG knockout. Secondly, the ino1 gene from Saccharomyces cerevisiae SC288 was introduced and the suhB gene was overexpressed to construct the complete biosynthetic pathway of myo-inositol in E. coli BL21. Ultimately, when 20 g/L glucose and xylose with a ratio of 3:2 were used as the mixed carbon source, the consumption rate of the total sugar was the fastest, and the yield of myo-inositol was 0.63 g/L in 50 mL/250 mL culture system. When the fermentation system was expanded to 1 L shake flask, the yield of myo-inositol was 0.69 g/L. This study contributes to the production of myo-inositol with mixed sugar as the carbon source.