3.1. Respiratory quotient
In order to investigate the extent of respiro-fermentative metabolism
of the different yeast strains included in this study (Table 1), the
RQ was determined under fully aerobic conditions, in the presence of
about 200 g/L of sugar and pH 3.5, as described in the Materials and
methods section. A simple stoichiometric calculation (Fig. S1), just taking
energy metabolism into account, indicates that the percentage of
sugar metabolised by respiration would be equivalent to 100/(3RQ-2).
Therefore, RQ values around 1.0, as those measured for a typical