Table 1.

Effects of combined glycerol addition on plasmid production and cell growth^*

Glycerol (g/L)	Relative DCW (%)	Relative PDY (%)	Relative SPDY (%)
0.0	100	100	100
2.0	126.3	96.5	76.4
4.0	101.6	170.6	167.9
6.0	113.5	100.0	88.0
8.0	125.0	38.1	30.4

^*Besides 5 g/L glucose in MMBL, different levels of glycerol was respectively supplemented into the medium. All the glycerol-containing cultures were harvested at 18 h, and no further increases in plasmid yield were achieved beyond the time. Values were the average of three independent determinations. PDY: plasmid DNA yield; SPDY: specific plasmid DNA yield