3.2 Cultivation
The cultivation results are summarized in Figures S1and S2 . Figure S1 indicates the time courses of cell
growth as OD660. Figure S2 demonstrates the
time courses of GFP fluorescence intensities. In the control experiment
using M9 minimal medium (Figure S1U and Figure S2U), the cell growth was
weak and the final yield was 1.11±0.25. GFP production was also weakly
induced, and the final GFP yield was
1.83×104±1.52×102 after 9 h. All of
the yeast extracts stimulated cell growth and GFP expression. Cell
growth and GFP drastically increased between 2 h and 4 h after
inoculation, and then the curves plateaued or decreased slightly. The
fold changes in growth after adding yeast extracts were between 2.72 and
4.50, and E3 was the best enhancer. The fold changes in GFP were between
1.62 and 2.84, and the best enhancer was E4. Experimental-grade yeast
extracts tended to stimulate more cell growth and GFP production than
manufacturing-grade yeast extracts. Interestingly, mixing both
experimental-grade and manufacturing-grade yeast extracts increased the
cell growth and GFP production.