3.2 High-density fermentation in a 5-L fermenter
A scale-up fermentation was carried out in a 5-L fermenter, and samples
were collected every 6 h to analyze OD600, total protein
concentration, and enzyme activity. The whole process of high-density
fermentation lasted for 108 h. As is showed in Fig. 2, in the fed-batch
with glycerol as carbon source, OD600 increased
continuously, reaching the highest value of 716±15 at 102 h, and then
decreased, which may be due to the fact that the dissolved oxygen can
not maintain the growth of such high density cells under the
experimental conditions. In the 102-h sample, the total protein
concentration and AGL activity in the culture supernatant were as high
as 0.732 mg/mL and 9.11 U/mL, respectively, which exhibited the same
growth trend as cell mass.
Figure 2