Figure 4.

NADPH supply to increase β-carotene production by different engineered Escherichia coli strains. Production of β-carotene (A) and biomass (B) by the different strains. The results represent the means from four independent experiments, and the error bars represent standard deviations. (C) Fed-batch fermentation of strain ECW4/p5C-nadK. Ultraviolet spectrophotometer was used to quantify the β-carotene production quickly during the fed-batch fermentation, and HPLC was used to re-quantify the production of some samples to confirm the quantitative accuracy of the absorption method after fermentation. Results showed that the quantifications obtained from the two methods were consistent.