Fig. 1

a Relative intensity of intracellular butanoyl-CoA measurements from widely targeted metabolic profiling of EL22 and BUOHSE. The y-axis represents the relative intensity of the metabolites, which was normalized to an internal standard. b Absolute intracellular concentration of butanoyl-CoA [pmol/mg-dry cell weight (dcw)kin EL22 and BUOHSE [18]. Samples were taken 67 h after IPTG induction. The error bars indicate standard deviations obtained from three replicates. c PCA score plot showing clear distinction between EL22 (in green circles) and BUOHSE (in yellow circles). d Loading scatter plot indicating metabolites that have influence on the clustering of the score plot. Relative intensity of two important metabolites: e acetyl-CoA and f (iso-) citrate. (Iso-) citrate in this study refers to iso-citrate and citrate as it is not possible to separate the two metabolites in our system. The y-axis represents the unit for the relative intensity of metabolites, which was normalized to an internal standard. Asterisks indicate significant differences in the strains (**p ≤ 0.01; ***p ≤ 0.001). All error bars indicate standard deviations obtained from three replicates