Table 2.
Effect of different nitrogen sources, tryptone concentrations and initial pH value on aflatoxin B1 degradation (%) by Aspergillus niger. The reactions were carried out at 32 °C with agitation at 200 rpm for 24 h. Sterile MTM was used to substitute microbial culture in the control. Results are expressed as means ± SEM of three replicates. In nitrogen sources group, means without a common letter denote significant differences according Least Significant Difference method (p < 0.05); in tryptone concentrations group and initial pH value group, means without a common letter denote significant differences according Least Significant Difference method (p < 0.01); SEM, standard error of the mean.
| Nitrogen sources | Aflatoxin B1 degradation (%) | Concentrations of tryptone (%) | Aflatoxin B1 degradation (%) | Initial pH value | Aflatoxin B1 degradation (%) |
|---|---|---|---|---|---|
| tryptone | 50.7 ± 0.6 a | 0.5 | 50.7 ± 0.6 A | 6.0 | 58.2 ± 0.9 A |
| Acidicase peptone | 47.0 ± 1.0 b | 0.7 | 50.4 ± 0.4 A | 6.5 | 50.7 ± 0.6 B |
| Proteose peptone | 45.1 ± 1.5 b | 0.9 | 49.8 ± 0.3 A | 7.0 | 49.2 ± 1.0 B |
| Ammonium nitrate | 39.1 ± 1.1 c | 0.3 | 38.9 ± 1.6 B | 7.5 | 47.9 ± 1.6 B |
| Mixed ammonium salt | 37.0 ± 1.0 c | 0.1 | 14.1 ± 0.9 C | 8.0 | 47.1 ± 1.1 B |
| Beef extract peptone | 33.3 ± 0.8 d | - | - | 5.5 | 35.2 ± 0.9 C |
| Peptone | 33.1 ± 1.6 d | - | - | 5.0 | 27.4 ± 1.8 D |
| Beef extract | 32.6 ± 1.1 d | - | - | - | - |
a, b, c, d, indicate significant differences between treatments at the 5% level of probability (p < 0.05).
A, B, C, D, indicate significant differences between treatments at the 1% level of probability (p < 0.01).