TABLE 1.
Influence of carbohydrate source(s) on growth and EPS production during S. thermophilus Sfi20 fermentationsa
| Carbohydrate source(s) (concn [M]) | μmax (h−1) (r2) | rmax (h−1)b (r2) | Biomassmax (g of CDM liter−1) (h) | (HMM-EPS)max (mg of PDM liter−1) (h) | (LMM-EPS)max (mg of PDM liter−1) (h) | (Total EPS)max (mg of PDM liter−1) (h) |
|---|---|---|---|---|---|---|
| Lactose (0.22) | 1.1 (0.997) | 0.5 (0.996) | 5.5 (11.25) | 685 (5.50) | 547 (3.75) | 880 (5.50) |
| Lactose (0.15) + fructose (0.14) | 1.2 (0.999) | 0.3 (0.999) | 5.0 (8.00) | 272 (12.00) | 435 (10.00) | 651 (12.00) |
| 0.3 (0.990) | ||||||
| Lactose (0.15) + galactose (0.14) | 0.9 (0.971) | 0.5 (0.999) | 3.3 (7.00) | 187 (7.00) | 494 (24.00) | 597 (7.00) |
| Lactose (0.15) + glucose (0.14) | 1.1 (0.954) | 0.4 (0.995) | 3.9 (5.75) | 1,162 (5.75) | 456 (23.50) | 1,238 (5.75) |
| 0.7 (0.880) | ||||||
| Glucose (0.42) | 1.2 (0.980) | 0.3 (0.999) | 5.4 (7.25) | 826 (7.25) | 570 (24.50) | 1,096 (8.75) |
| Glucose (0.28) + fructose (0.14) | 1.2 (0.993) | 0.4 (0.995) | 4.8 (7.00) | 401 (10.50) | 537 (7.00) | 771 (7.00) |
| 0.1 (0.999) | ||||||
| Glucose (0.28) + galactose (0.14) | 1.1 (0.977) | 0.7 (0.999) | 4.4 (14.75) | 326 (12.75) | 433 (13.25) | 691 (12.00) |
| Glucose (0.28) + lactose (0.07) | 1.2 (0.966) | 0.7 (0.962) | 5.4 (26.50) | 793 (16.50) | 390 (13.50) | 1,018 (16.50) |
| 0.1 (0.993) |
a
Fermentations were performed in MRS broth at 42°C and at a controlled pH of 6.2. The biokinetic parameters μmax and rmax were estimated through modeling of the experimental data.
b
Dual values refer to the respective carbohydrate sources.