Table 5.
Key electron sinks that compete with H2 production**
| Electron Sink | Pathway | Reaction | Responsible Genes |
|---|---|---|---|
| PHB | Butanoate Metabolism | RXN0589 | RSP0382, RSP1257 |
| H2S | Sulfur Metabolism | RXN0866 | RSP1942 |
| Glycogen | Starch & Sucrose Metabolism | RXN0849 | RSP2887 |
| Formate | One Carbon Pool by Folate | RXN0323 | RSP0944 |
| Glycerate | Glycerolipid Metabolism | RXN0030 | RSP1292, RSP1507, RSP3740, RSP4003, RSP2372 |
| 4-Coumarate | Nitrogen Metabolism | RXN0495 | RSP3574 |
| Methanethiol | Cysteine & Methionine Metabolism | RXN1096 | RSP1851 |
| 4-Aminobutyraldehyde* | Glycolysis/Gluconeogenesis | RXN0031 | RSP4003, RSP3740, RSP2372, RSP1507, RSP1292 |
| Chitobiose* | Amino Sugar and Nucleotide Sugar Metabolism | RXN0040 | RSP2941 |
| D-1-Aminopropan-2-ol O-phosphate* | Cobalamin Metabolism | RXN0653 | RSP0430 |
| Heme* | Heme Metabolism | RXN0632 | RSP1197 |
| Ethanolamine* | Glycerophospholipid Metabolism | RXN0378 | RSP0113 |
*Competitors for sub-optimal growth conditions only.
** Secretion of central metabolism intermediates pyruvate, fumarate, and malate were blocked, assuming that cells are programmed to reuse these compounds as carbon sources even after secretion. This was based on observations with batch cultures [3], but might not hold true for continuous cultures.