Microbes and Metabolism - Environmental Biotechnology: Theory and Application - page 30

Fermentation is therefore an option under conditions where there is an active elec-
tron transport chain as discussed in the following section, but becomes essential
when fermentation is the only method for regenerating NAD + .
As noted above, the end product of fermentation for any given carbon source
may be diagnostic of the identity of a specific organism. This is more relevant for
bacteria than for yeast or other eukaryotic cells and arises from the predisposition
of that organism, to use a particular fermentation pathway. These are described
in detail in Mandelstam and McQuillen (1973) and are summarised in Figure 2.8.
Identification by the product of carbohydrate catabolism is somewhat specialised
and is very thoroughly set out in Cowan and Steel's Manual for the Identification
of Medical Bacteria (Barrow and Feltham 1993).
Figure2.8 Fermentations