This study will access kinetics parameters from different strains of yeast (Saccharomyces cerevisiae) which are commonly used as fermentation starters by sugarcane industries. This study will cover these strains: BG-1, PE-2, CAT-1. Baker's yeast will be used as control. Experiment will be conducted in triplicates. Fermentations will be held in beakers with 1 liter of sugarcane and molasses must. A blend of sugarcane and molasses must will also be used. Musts will be prepared under 30ºBrix, pH 5,0 and 30ºC conditions. Pre-tests will be carried out to standardize the technique but mainly to access the quantity of yeast necessary to stabilize the Brix within 8-10 hours from the start of fermentation. To determine kinetics parameters (µmax on alcohol and yeast biomass productions, ethanol productivity, and generation time), hourly measures of carbon dioxide and biomass will be done. Among these parameters other two conversion factors will be calculated; substrate into biomass (YX/S) and substrate into ethanol (YP/S).
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