TABLE 2.
Percentage of 13C labeling on the fermentation products derived from the metabolism of different substrates by cell suspension of T. zilligii grown on tryptonea
| Substrate(s) | Value for product:
|
||||
|---|---|---|---|---|---|
| Acetate
|
Formate
|
||||
| Total amt (μmol/mg of protein) | 13CH3COO− (%) | CH313COO− (%) | Total amt (μmol/mg of protein) | H13COO− (%) | |
| [3-13C]pyruvate | 2.70 | 82 | — | 0.05 | — |
| [1-13C]pyruvate | 2.80 | — | — | 0.05 | 20 |
| Glucose and [1-13C]pyruvate | 3.13 | — | — | 0.13 | 23 |
| Glucose and [13C]bicarbonate | 1.2 | — | — | 0.23 | 9 |
a
Cell suspensions were incubated at 75°C for 2 h with the different substrates at a 15 mM concentration each. Fermentation products were quantified in supernatants by proton NMR using formate as a standard. Percentages of 13C labeling were calculated by integration of the respective resonances in the 1H spectra. The natural abundance of 13C (1.1%) was subtracted. —, not detected.