The mean values of RE,H and RGly,H assumed similar values for
runs carried out both in presence and absence of ethanol in the initial
reaction medium (Table 3). This experimental evidence show that the
reaction involved in the rate determining step is one of those coming
first the hexose cleavage to two triose phosphates regardless the initial
concentration of ethanol in the reaction medium. The ratio between the
kinetic constant related to time evolution of D-glucose and D-fructose
in experimental runs characterized by an high initial concentration
of ethanol assumed a similar value (kG/kF ~ 3:1) both for S. cerevisiae
strain than for S. bayanus one. This value was lower than that related
to the runs carrying out in absence of ethanol in the initial reaction
medium (kG/kF ~1.6:1), showing that this alcohol induced a sensible
reduction of fructose conversion so that a great amount of this sugar
can be found unconverted in the reaction medium (> 25%) both using
strain C and strain B