Table 3.
Comparison of optimal conditions at each step of GlcNAcase production by Aeromonas caviae CHZ306
| Variables | Evaluation steps | |||
|---|---|---|---|---|
| Basal conditionsa | Nutritional conditions | Physicochemical conditions | ||
| Cultivation system | Shake flasks | Shake flasks | Shake flasks | Stirred-tank bioreactor |
| Primary carbon source | Colloidal α-chitin | Colloidal α-chitin | Colloidal α-chitin | Colloidal α-chitin |
| Secondary carbon source | - | Corn steep liquor, peptone A | Corn steep liquor, peptone A | Corn steep liquor, peptone A |
| Nitrogen source | (NH4)2SO4 | Corn steep liquor, peptone A | Corn steep liquor, peptone A | Corn steep liquor, peptone A |
| C:N ratio | 0.7 | 4.4 | 5.2 | 5.2 |
| Colloidal α-chitin (%) | 1.0 | 1.0 | 5.0 | 5.0 |
| pH | 7.0 | 7.0 | 8.0 | 8.0 |
| Temperature (°C) | 28 | 28 | 34 | 34 |
| Agitation (rpm) | 180 | 180 | 180 | 250 |
| Aeration (vvm) | - | - | - | 1.75 |
| kLa (h−1) | - | - | - | 55.2 |
| Time of max. activity (h) | 96 | 96 | 36 | 12 |
| GlcNAcase activity (U.L−1) | 3.7 | 78.3 | 192.5 | 173.4 |
| GlcNAcase productivity (U.L−1.h−1) | 0.04 | 0.82 | 5.35 | 14.45 |
aBasal conditions refer to those used in our previous studies (data not shown)