Table 1.
Effect of carbon source and inducer on production of muramidase. Muramidase activities in batch cultures (M9 medium) of BL21(DE3) pET21 mur performed with either glucose or glycerol as initial carbon source and by induction with lactose, whey or IPTG. Induction was started at OD500 = 0.8 and activities were measured 5 hours after induction. In samples without inducer muramidase activity was zero.
| Carbon source | Concentration of carbon source, g l-1 Initial at start of induction | Inducer | Concentration of inducer, g l-1 | Activity of muramidase, U ml-1 | |
| Glucose | 4.0 | 1.5 | IPTG | 0.5 mM | 585 (100%) |
| Glucose | 4.0 | 1.5 | Lactose | 6.8 | 0 (0%) |
| Glucose | 4.0 | 1.5 | Whey | 6.8 (lactose) | 0 (0%) |
| Glycerol | 5.0 | n.d. | IPTG | 0.5 mM | 535 (91%) |
| Glycerol | 5.0 | n.d. | Lactose | 6.8 | 520 (89%) |
| Glycerol | 5.0 | n.d. | Whey | 6.8 (lactose) | 518 (89%) |
n.d. – not determined