Fermentation capacity was determined by cultivating each strain in 50 mL of agave juice. Initial sugar concentration (fructose + glucose) was adjusted to 120 g/L, as described previously.Nitrogen content of the agave juice was measured the by the micro-Kjeldahl method, as described previously. Then, the carbon/nitrogen (C/N) ratio was adjusted to 73 by adding ammonium sulfate. Incubations were carried out at 28C for 72 h with sampling at 8-h intervals. Biomass concentration was determined in a Neubauer chamber. Samples were filtered through a 0.45-mm nylonfilter and the liquid was stored at 80C until analysis. Specific rates of sugar consumption (KS) and ethanol production (KE) were calculated by fitting afirst-order kinetics equation to the corresponding experimental data, as reported previously .All fermentations were performed in triplicate.