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Fig. 9.
Effect of various chemicals on CNXK100 thermostable protease activity_
| Group | Chemical | Concentration | Residual activity (%) |
|---|---|---|---|
| Control | – | – | 100.00 |
| Organic solvents | Methanol | 10.0% | 89.28 ± 3.63 |
| Ethanol | 86.54 ± 2.36 | ||
| Isopropanol | 79.47 ± 1.85 | ||
| Butanol | 43.93 ± 2.32 | ||
| Chloroform | 86.54 ± 2.34 | ||
| Surfactants | Triton X-100 | 1.0% | 101.27 ± 2.58 |
| Tween 20 | 88.13 ± 1.93 | ||
| Tween 80 | 92.06 ± 3.21 | ||
| SDS | 53.42 ± 3.05 | ||
| Bleaching agents | NaClO | 0.5% | 105.86 ± 0.57 |
| 1.0% | 111.36 ± 0.86 | ||
| 1.5% | 113.17 ± 1.62 | ||
| 2.0% | 114.11 ± 0.53 | ||
| 2.5% | 121.47 ± 2.28 | ||
| 3.0% | 120.75 ± 1.34 | ||
| H2O2 | 0.5% | 89.21 ± 2.03 | |
| 1.0% | 77.85 ± 9.51 | ||
| 1.5% | 74.12 ± 10.34 | ||
| 2.0% | 71.68 ± 12.29 | ||
| 2.5% | 75.51 ± 2.12 | ||
| 3.0% | 66.96 ± 13.07 | ||
| Proteolytic enzymes | Pepsin | 0.1 mg/ml | 101.54 ± 1.43 |
| Trypsin | 68.97 ± 0.51 | ||
| Chymotrypsin | 91.34 ± 0.13 | ||
| Proteinase K | 10.80 ± 0.44 |
Purification of thermostable protease from Streptomyces sp_ CNXK100_
| Purification steps | Total protein (mg) | Total activity (U) | Specific activity (U/mg) | Activity recovery (%) | Purification level |
|---|---|---|---|---|---|
| Crude extract | 54.64 | 1.14 x 106 | 2.09 x 104 | 100.00 | 1.00 |
| Heat-treatment | 18.62 | 4.14 x 105 | 2.22 x 104 | 36.32 | 1.06 |
| Fractional precipitation with 60% (NH4)2SO4 | 0.81 | 1.95 x 105 | 2.41 x 105 | 17.11 | 11.53 |
| Gel filtration | 0.011 | 2.63 x 104 | 2.40 x 106 | 2.31 | 114.83 |