Table 2.
Metabolic features of thermophilic hydrogen producers (modified and continued from Chou et al. 2008)
| Organism | Fermentability of feedstocks/polymers | CCR | Auxotrophy to amino acids | Electron carriers | Hydrogenasea | Reductant sink | References |
|---|---|---|---|---|---|---|---|
| Clostridia (Cl. thermocellum) | Starch, cellulose, lignocellulose | Yes | No | NADH, ferredoxin | Uptake, Fe-only, FNOR | Alcohol, organic acids, lactate | Johnson et al. (1981), Desvaux (2006) |
| Thermococcales (Pyroccus furiosus) | Maltose, cellobiose, β-glucans, starch | No | Yes | Ferredoxin | MBH, NiFe-only, FNOR | Alanine, ethanol | Hoaki et al. (1994), Maeder et al. (1999), Silva et al. (2000), Robb et al. (2001) |
| Thermotogales (T. maritima/T. neapolitana) | Cellulose, xylan, starch, cellobiose, lignocellulose | Yes | No | NADH, ferredoxin | Fe-only, NMOR, FNOR | Lactate, alanine | Schönheit and Schäfer (1995), Vargas and Noll (1996), Rinker and Kelly (2000), Bonch-Osmolovskaya (2001) |
| Caldicellulosiruptor (C. saccharolyticus) | Cellulose (avicel, amorp.), xylan, pectin, α-glucan, β-glucan, lignocellulose, guargum | No | No | NADH, ferredoxin | Fe-only, NiFe-only | Lactate, ethanol | Rainey et al. (1994), de Vrije et al. (2007), van de Werken et al. (2008), Ivanova et al. (2008), Willquist and van Niel (2012) |
| Thermoanaerobacter (T. tengcongensis MB4) | Starch, sucrose, glycerol | Yes | Yes | NADH, Ferredoxin | Fe-only, NiFe-only | Ethanol | Xue et al. (2001), Warner and Lolkema (2003), Soboh et al. (2004) |
CCR carbon catabolite repression
aTypes of hydrogenases—uptake, NiFe type hydrogen uptake hydrogenase, FNOR (ferredoxin:NAD(P)H oxidoreductase), Fe-only, Fe-only evolution hydrogenase, NiFe-only, NiFe-only evolution hydrogenase, NMOR (NADH:methylviologen oxidoreductase) and MBH (membrane-bound hydrogenase)