Table 1.
Effect of fermentation period, pH, temperature, carbon sources, nitrogen sources and metal chlorides on alkaline serine protease production by Bacillus caseinilyticus
| Fermentation period (h) | Protein concentration (mg/ml) |
|---|---|
| 26 | 39.30 ± 2.5 |
| 48 | 42.67 ± 3.5 |
| 74 | 34.65 ± 4.0 |
| 98 | 28.76 ± 2.8 |
| 120 | 24.35 ± 2.1 |
| pH | |
| 6 | 0 |
| 7 | 29.30 ± 3.5 |
| 8 | 33.67 ± 2.5 |
| 9 | 49.76 ± 1.5 |
| 10 | 28.16 ± 2.6 |
| 10.5 | 0 |
| 12 | 0 |
| Temperature (°C) | |
| 20 | 0 |
| 30 | 39.10 ± 2.5 |
| 37 | 49.99 ± 3.5 |
| 40 | 39.76 ± 1.5 |
| 50 | 28.16 ± 2.9 |
| 60 | 20.22 ± 1.8 |
| 70 | 0 |
| Carbon sources | |
| Glucose | 33.55 ± 1.9 |
| Sucrose | 42.66 ± 1.8 |
| Lactose | 39.16 ± 1.8 |
| Fructose | 48.16 ± 1.9 |
| Maltose | 21.92 ± 1.7 |
| Nitrogen sources | |
| Ammonium chloride | 0 |
| Malt extract | 43.99 ± 1.9 |
| Yeast extract | 31.19 ± 1.2 |
| Peptone | 39.19 ± 1.0 |
| Skim milk | 47.92 ± 2.1 |
| Metal chlorides | |
| CaCl2 | 42.35 ± 2.1 |
| MgCl2 | 42.55 ± 3.9 |
| ZnCl2 | 39.77 ± 2.8 |
| FeCl2 | 38.68 ± 2.9 |
| CuCl2 | 31.29 ± 1.8 |
| Control (only basal medium) | 12.45 ± 3.7 |
All the results were presented as mean ± SD