Table 1.
Effect of different nitrogen sources on growth and γ-PGA production by Bacillus subtilis and Bacillus licheniformis. Data represent the mean of 3 different readings ± standard deviation.
| Nitrogen sources | γ-PGA production (g/l) |
Bacterial growth (g/l) |
||
|---|---|---|---|---|
| B. subtilis | B. licheniformis | B. subtilis | B. licheniformis | |
| Yeast extract | 12.58 ± 1.2 | 10.22 ± 1.12 | 17.88 ± 0.99 | 14.55 ± 0.25 |
| Peptone | 11.45 ± 1.0 | 9.84 ± 2.00 | 15.24 ± 0.52 | 12.15 ± 0.12 |
| Malt extract | 20.15 ± 0.8 | 8.56 ± 1.46 | 14.52 ± 0.64 | 10.22 ± 0.14 |
| Soybean extract | 37.45 ± 0.2 | 6.47 ± 1.89 | 13.20 ± 0.22 | 9.24 ± 0.84 |
| NH4Cl | 53.68 ± 0.02 | 31.28 ± 1.25 | 12.5 ± 0.06 | 9.36 ± 0.05 |
| NH4SO4 | 42.89 ± 0.00 | 28.44 ± 1.50 | 10.0 ± 0.10 | 7.26 ± 0.11 |
| NH4NO3 | 49.11 ± 0.65 | 22.35 ± 0.05 | 8.12 ± 0.07 | 4.44 ± 0.16 |
| NaNO3 | 30.45 ± 1.5 | 20.18 ± 0.08 | 7.92 ± 0.00 | 3.12 ± 0.13 |
| KNO3 | 40.28 ± 1.0 | 19.78 ± 0.09 | 7.10 ± 0.68 | 2.51 ± 0.21 |