TABLE 3.
Thresholds for hydrogen of selected H2-consuming bacteria
| Microorganism | Incubation (temp [°C]) | Gas com- position | No. of determi- nations | Mean H2 (ppm)a ± SEM |
|---|---|---|---|---|
| A. ruminis 139B | + (38) | H2-N2-CO2b | 33 | 4,660 ± 39 |
| + (38) | N2-CO2c | 18 | 147 ± 15 | |
| − | N2-CO2 | 4d | 39 ± 3 | |
| A. ruminis 190A4 | + (38) | H2-N2-CO2 | 34 | 3,830 ± 69 |
| + (38) | N2-CO2 | 13 | 68 ± 22 | |
| − | N2-CO2 | 4d | 41 ± 1 | |
| Methanogen 10-16B | + (38) | H2-N2-CO2 | 32 | 126 ± 4 |
| + (38) | N2-CO2 | NDe | ND | |
| S. termitida | + (30) | H2-N2-CO2 | 20 | 871 ± 88 |
| + (30) | N2-CO2 | 15 | 1,200 ± 95 | |
| − | N2-CO2 | 4d | 12 ± 1 | |
| A. woodii | + (30) | H2-N2-CO2 | 33 | 362 ± 9 |
| + (30) | N2-CO2 | 17 | 328 ± 14 | |
| − | N2-CO2 | 4d | 35 ± 3 |
a
Gas-phase concentration at the end of incubation. To convert to micromolar H2 in the liquid phase, multiply parts per million of H2 by 7.62 × 10−4 and 7.36 × 10−4 for tubes incubated at 30 and 38°C, respectively (45).
b
1.2:75.2:23.6 (vol%).
c
80:20 (vol%).
d
Analyzed for H2 immediately after initial pressurization with N2-CO2.
e
ND, not determined.