TABLE 2.
Folate production by S. thermophilus strain B119 and L. MG1363 in continuous cultures at different pHsa
| pH |
S. thermophilusb
|
L. lactisb
|
||||||
|---|---|---|---|---|---|---|---|---|
| Extracellular folate (μg/liter) | Intracellular folate (μg/liter) | % Excreted | Total folate (μg/liter) | Extracellular folate (μg/liter) | Intracellular folate (μg/liter) | % Excreted | Total folate (μg/liter) | |
| 5.0 | NDb | ND | ND | ND | 3 ± 2 | 32 ± 5 | 8 | 37 |
| 5.5 | 77 ± 7 | 65 ± 15 | 54 | 142 | 4 ± 2 | 36 ± 3 | 9 | 44 |
| 6 | 94 ± 8 | 292 ± 30 | 24 | 386 | 6 ± 1 | 42 ± 9 | 11 | 54 |
| 6.5 | 103 ± 8 | 431 ± 30 | 19 | 534 | ND | ND | ND | ND |
| 7.0 | ND | ND | ND | ND | 16 ± 1 | 91 ± 9 | 8 | 107 |
| 7.5 | ND | ND | ND | ND | 15 ± 1 | 88 ± 1 | 8 | 102 |
a
S. thermophilus strain B119 was cultivated in modified M17 medium (potassium phosphate instead of β-glycerophosphate) with 0.5% lactose as the growth-limiting substrate, and L. lactis was grown in CDM (26) without phenylalanine, PABA, and folate, with 0.5% glucose as the growth-limiting substrate.
b
Extracellular, intracellular, and total folate concentrations produced and percent excreted by the species. ND, not determined.