Fig. 3.

Fed-batch culture by E. coli BL21(DE3)pLysS (pBAD/3C/bTGase) with DO-stat feeding using Terrific broth (TB). In approximately 16 h, the culture temperature was reduced to 20 °C, the pro-bTGase gene was induced by the addition of 0.4 mM IPTG, and cultivations proceeded for 4 h; gene 3C protease was induced by the addition of 0.2% L-arabinose, followed by 10 h of cultivation. A (■) biomass DCW (g/L); (△) glucose (g/L); (▽) acetate (g/L). B (○) STIR (rpm); (●) pO₂ (%). All experimental runs were performed in duplicates. The vertical gray lines mark the batch and fed-batch strategy, and the vertical black lines mark the time of induction of pro-bTGase and 3C protease