TABLE 1.
Average stoichiometric and kinetic properties of chain elongating communities in SBRs at different pH during stable operationa.
| pH 7 | pH 5.5 | |
| Ethanol consumption (%) | 47 ± 4 | 25 ± 3 |
| Acetate consumption (%) | 79 ± 3 | 66 ± 4 |
| Electrons converted to caproate (%) | 71 ± 6 | 30 ± 5 |
| EtOH:H2 ratio (mol mol–1) | 3.0 ± 0.3 | 3.5 ± 0.2 |
| Donor:Acceptor consumption ratiob (mol mol–1) | 1.9 ± 0.1 | 2.1 ± 0.2 |
| YX/EtOH (CmolX mol–1) | 0.11 ± 0.02 | 0.05 ± 0.01 |
| qEtOH (mol CmolX –1 h–1) | 0.54 ± 0.08 | 1.12 ± 0.13 |
aOnly data between cycle 60 and cycle 96 is included in these calculations. bElectron acceptor consumption was calculated as the summed consumption of acetate and butyrate. Following the canonical stoichiometry for chain elongation, it was assumed that for every mol of caproate produced, 1 mol of butyrate was consumed.