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Fig. 6 | Biotechnology for Biofuels

Fig. 6

From: Engineering and application of synthetic nar promoter for fine-tuning the expression of metabolic pathway genes in Escherichia coli

Fig. 6

Comparison of 2,3-BDO production with the expression of ilvBN, aldB, and bdh1 under control of the 3 synthetic nar promoters. a Combination of expression modules of ilvBN, aldB, and bdh1 genes. Modules are Si, Ii, Wi, Sa, Ia, Wa, Sb, Ib, and Wb; S stands for strong promoter, I for intermediate promoter, W for weak promoter, i for ilvBN, a for aldB, and b for bdh1. b Titer of 2,3-BDO obtained by expressing 7 modules in flask cultures. The positive control NiNa-Nb is a module expressing ilvBN, aldB, and bdh1 genes with a wild-type nar promoter. Fed-batch cultivation of E. coli expressing SWS (c) and NNN (d) modules. The SWS module expressed ilvBN with a strong, aldB with a weak, and bdh1 with a strong nar promoter. The positive control NNN module expressed ilvBN, aldB, and bdh1 genes with a wild-type nar promoter. Black square, 2,3-BDO; hollow circle, cell growth; hollow triangle, glucose; solid gray circle, DO level; red arrows, the time of DO downshift (induction)

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