n-Butanol pathway intermediates at 24 h. Bars and strains: black bars, ESY4; gray bars, ESY7; white bars, ESY11. (A) All pathway intermediates in strains ESY4, 7 and 11. (B) HbCoA, CrCoA and BtCoA intermediates in strains ESY4 and ESY7. Levels of AcCoA were similar except for strains ESY11 (A). Levels of 3-hydroxybutyryl-CoA (HbCoA) and butyryl-CoA (BtCoA) were notably higher in ESY7 compared to ESY4, while crotonyl-CoA (CrCoA) was relatively similar in the two strains. Values and error bars represent the mean and standard deviation of triplicate cultures.