Figure 3

Effect of fermentation process design and induction temperature on growth of collagen-producing E. coli strains. Cell concentration was estimated by measuring optical density at 600 nm. See Table 1 for experimental details. (A) Shake flask and low cell density processes.♦, VCL, shake flask, complex medium (2xYT); ▲, VCL, shake flask, defined medium; ■, VCL, bioreactor batch process (low cell density); ●, VCLH, bioreactor batch process (low cell density). (B) High cell density processes. ♦, VCLH, bioreactor fed-batch process, induction at 25°C for 10 hours; ▲, VCL, bioreactor fed-batch process, induction at 25°C for 10 hours; ●, VCL, bioreactor fed-batch process, induction at 15°C for 24 hours; ■, VCL, bioreactor fed-batch process, induction for 24 hours with stepwise temperature reduction.