Fig. 1

Metabolic flux distributions simulated by non-optimized ACHR method under anaerobic conditions. The abbreviations and arrows in black color represent metabolites and reactions, respectively, whereas the red arrows refer to the biomass formation reaction. The rectangles and histograms denote the average flux values of reactions and the probability distributions for the values of reactions, respectively. Therein, the colors of both the numbers in the rectangles and the lines in the histograms indicate different strains as follows: black, green, red, and blue indicate wild-type E. coli, ldhA mutant, pflB mutant, and NZN111, respectively