TABLE 2.
Fermentation product formation in wild-type B. subtilis and various fermentation gene mutantsa
| B. subtilis strain (relevant genotype) | Electron acceptor (10 mM) | Lactate (mM) | Acetate (mM) | 2,3-Butanediol (mM) | Total product concn (mM) | Concn of cells (g [wet wt]/liter) |
|---|---|---|---|---|---|---|
| 168 (wild type) | Nitrate | 23.3 | 16.4 | 16.7 | 56.4 | 8.0 |
| BSIP1190 (lct) | Nitrate | 1.1 | 14.3 | 13.4 | 28.8 | 2.0 |
| BSIP1171 (pta) | Nitrate | 9.0 | 3.7 | 4.2 | 16.9 | 4.3 |
| BSIP1173 (als) | Nitrate | 38.3 | 18.1 | NDb | 56.4 | 7.8 |
| BSIP1174 (pta als) | Nitrate | 2.7 | 1.7 | ND | 4.4 | 2.4 |
| 168 (wild type) | Nitrite | 25.9 | 16.0 | 11.1 | 53.0 | 7.3 |
| BSIP1190 (lct) | Nitrite | 0.9 | 14.4 | 13.1 | 28.4 | 2.7 |
| BSIP1171 (pta) | Nitrite | 12.3 | 3.0 | 1.1 | 16.4 | 3.0 |
| BSIP1173 (als) | Nitrite | 38.0 | 15.5 | ND | 53.5 | 7.5 |
| BSIP1174 (pta als) | Nitrite | 2.0 | 1.0 | ND | 3.0 | 2.1 |
| 168 (wild type) | 38.4 | 13.3 | 9.5 | 61.2 | 7.3 | |
| BSIP1190 (lct) | 3.0 | 7.0 | 7.5 | 16.5 | 1.8 | |
| BSIP1171 (pta) | 28.8 | 2.5 | 18.2 | 49.5 | 3.2 | |
| BSIP1173 (als) | 39.4 | 12.5 | ND | 51.9 | 7.4 | |
| BSIP1174 (pta als) | 15.0 | 1.1 | ND | 16.1 | 2.0 |
a
The indicated B. subtilis strains were incubated anaerobically for 10 h at 37°C in defined minimal media using 50 mM glucose and 50 mM pyruvate as carbon sources. Fermentation products were isolated from the growth media and quantified using HPLC as described in Materials and Methods.
b
ND, not detectable.