Fig. 3
Screening of E. coli single mutant strains and optimization of the genetic background for D-DIBOA production. a Screening of E. coli single mutant strains transformed with the vector pBAD-NfsB for improved D-DIBOA synthesis. Bar charts show relativized values of D-DIBOA concentration (mM) and SP (mmol D-DIBOA/gCDW x h) for single mutant strains respect to the wild type strain at 22 h. In no case the coefficient of variation were higher than 11%. In the left-hand column, the mutant strains assayed in this work are listed and in the right-hand column the metabolic pathways in which the mutated gene is involved are indicated. In order to facilitate the analysis of the screening, the mutant strains are listed in the same order as in Table 1. b Scatter plot of mean and SD (from at least 9 replicates) of D-DIBOA concentration in the reference, the single and double knockout strains. c BY and d SP for the single and double mutant strains under the screening conditions. Asterisks (*) show the pair of strains that have no statistically significant differences (p value > 0.05) for BY or SP. The parameters in b, c and d were evaluated at 0, 4, 8, 18 and 22 h time points