Figure 10.

Conversion pathways for the anaerobic fermentation of glucose and the subsequent options for industrial valorization; between brackets, the Gibbs free energy per electron (kJ/mol) calculated from the reaction of each compound to CO₂ and H₂O. The resulting Gibbs energies show that both ethanol and lactate offer the opportunity for further conversion to medium chain length fatty acid, while volatile fatty acid can only be converted either to methane (anaerobically) or to molecules that are produced aerobically, like PHA [Color figure can be viewed at wileyonlinelibrary.com]