Fig. 5
Soluble RH production in EnPresso B-based UYF shake flask cultivations. E. coli BQF8RH was cultivated in 50 mL EnPresso B medium with/out boosting in 250 mL UYF at 30 °C. For autoinduction 50 µM IPTG or 2 g L−1 lactose were added to induce RH production at the beginning of the cultivation. For comparison classic single shot IPTG induction was performed. For IPTG or lactose autoinduction cultures were induced from the beginning of the cultivation and cells harvested after 24 h of growth. For classic IPTG induction cells were cultivated for 18 h without inducer. Subsequently, RH production was induced by addition of 50 µM IPTG and finally cells were harvested after 24 h of induction resulting in a total process time of 42 h. The induction time points are indicated by black arrows. A Growth curve, B Specific, volumetric and space–time yield of RH calculated from Coomassie stained gels after affinity purification and quantification with ImageJ as described in “Materials and methods”