Production of d-ribose by metabolically engineered Escherichia coli

[Display omitted] •Transketolase-deficient E. coli was constructed to produce d-ribose from xylose.•d-Ribose produced in the E. coli was identical to standard d-ribose in HPLC and LC/MS analyses.•The transketolase-deficient E. coli was further engineered to uptake glucose and xylose simultaneously for facilitating d-ribose production.•The simultaneous uptake of glucose and xylose in the E. coli resulted in a 5-fold improvement of d-ribose production. Escherichia coli was metabolically engineered for the production of d-ribose, a functional five-carbon sugar, from xylose. For the accumulation of d-ribose, two genes of transketolase catalyzing the conversion of d-ribose-5-phosphate to sedoheptulose-7-phosphate in pentose phosphate pathway were disrupted to create a transketolase-deficient E. coli SGK013. In batch fermentation, E. coli SGK013 grew by utilizing glucose and then started to produce d-ribose from xylose after glucose depletion. E. coli SGK013 produced 0.75g/L of d-ribose, which was identical to the standard d-ribose as confirmed by HPLC and LC/MS analyses. To improve D-ribose production, the ptsG gene encoding the glucose-specific IICB component was disrupted additionally, resulting in the construction of E. coli SGK015. The carbon catabolite repression-negative E. coli SGK015 utilized xylose and glucose simultaneously and produced up to 3.75g/L of d-ribose, which is a 5-fold improvement compared to that of E. coli SGK013.