Fig. 7
From: Multilevel optimisation of anaerobic ethyl acetate production in engineered Escherichia coli
Effect of pH-control and continuous ethyl acetate stripping on product yield and volumetric productivity. a Final product yields achieved by cultures producing unprocessed Kma Eat1 and trEat1 K-30 in the presence of 0.05 or 0.1 mM IPTG. The numbers above the bars represent the carbon recovery of the fermentations. b Final product yields achieved by cultures producing unprocessed Wan Eat1 and trEat1 N-13 in the presence of 0.01 mM IPTG. The numbers above the bars represent the carbon recovery of the fermentations. c, d The volumetric productivity of ethyl acetate (QEA) of the fermentation shown in a and b, respectively. Strains were grown under anaerobic conditions in minimal medium containing 55 mM glucose. Genes were expressed in E. coli BW25113 ΔackAΔldhA (DE3) from a series of pET26b plasmids. The cumulative mass of ethyl acetate, CO2 and H2 removed by gas stripping was divided by the culture volume of the reactor and in case of ethyl acetate added to concentrations measured in the liquid. Formate and CO2 yields were lumped together to compensate for the variation in H2 formation. Experiments were performed as biological duplicates or triplicates; error bars represent the standard deviation. Eat1 unprocessed Eat1, trEat1 truncated Eat1