Figure 1

Overview of conducted experiments. Cultivations were performed with four E. coli BL21 (DE3) variants carrying the genes for 3-hydroxybutyryl-CoA dehydrogenase (E. coli HBD), glucose 1-dehydrogenase (E. coli GDH), 3-hydroxybutyryl-CoA dehydrogenase and glucose 1-dehydrogense (E. coli HBD-GDH), and alcohol dehydrogenase A (E. coli ADH-A) in three different complex media. The non-inducing TB medium and auto-inducing TB+lactose medium were prepared with yeast extracts from five different suppliers and, in total, eight different lots which are listed in Table 1. Additionally, cultivations were performed with two different lots of the commercially available Overnight Express (OnEx) auto-induction medium