1. Fed-batch fermentation
Fed-batch experiments were performed with glucose maintained at around 5
g/L to determine the growth characteristics of YL-C11 (Figure 1). Cell
growth increased rapidly during the 12-42th h
fermentation. After 42 h fermentation, cell growth entered the
stationary period. Although cell growth was in a stationary phase, the
synthesis of β-carotene continued. It was not until the
96th h of fermentation that the synthesis of the
β-carotene trend finally stopped. Glucose (1200 g) was consumed during
fermentation. The DO value decreased rapidly in the first 28 h of
fermentation and reached 0% when the fermentation time extended from 28
to 120 h. Cell biomass reached 73.5g, and β-carotene
concentration
reached 0.3g/L at the end of fermentation. The results showed that the
biomass and β-carotene concentration were at a low level, and there is
potential for improvement.