Figure 4

Time course of cell dry weight (CDW), P4HB content and P4HB concentration during a pulse feeding fed-batch culture of E . coli JM109 (pKSSE5.3). Glycerol and 4-hydroxybutyric acid were used as carbon source and precursor, respectively. Cultivation was conducted at 32°C in a 1L bioreactor with an initial volume of 600mL of modified M9 medium plus 20gL^-1 glycerol, 6gL^-1 Na-4HB, 2gL^-1 acetic acid, 0.5gL^-1 NZ-amines, 0.015gL^-1 thiamine and 100mgL^-1 ampicillin. Feeding solution was added to the bioreactor when glycerol in the medium was close to depletion, indicated by pO₂ signal. Arrow #1, feeding of 12.5gL^-1 glycerol+2.5gL^-1 Na-4HB+1.1gL^-1 acetate at 30h; Arrow #2, feeding of 25.0gL^-1 glycerol+2.1gL^-1 acetate at 39h; Arrow #3, feeding of 2.5gL^-1 Na-4HB at 41h; Arrow #4, feeding of 25.0gL^-1 glycerol+2.1gL^-1 acetate+2.5gL^-1 Na-4HB at 44h; Arrow #5, feeding of 25.0gL^-1 glycerol+2.1gL^-1 acetate+6gL^-1 Na-4HB at 49.5h. The data are the average numbers of duplicates.