OPTIMISATION ET MODELISATION DES PARAMETRES ENVIRONNEMENTAUX SUR LA CROISSANCE DE "Saccharomyces cerevisiae" ISOLE SUR REBUT DE DATTE

Abstract

This work focused on the metabolic and kinetic analysis of two strains of yeasts Saccharomyces cerevisiae (S1 and S3), isolated from juice of dates poorer quality Degla-Beida and Mech-Degla respectively. Based on the methodology of the experimental plans to study the influence of environmental factors (pH, temperature, initial concentration in ethanol and salinity) upon the growing of the yeasts. The parameter value of the growing of Saccharomyces cerevisiae are fixed according to the results of the experiment plan and the data collection was made according to a centered composite plan, so as to study the linear effects, the quadratic effects and the interactions between factors. The results obtained show that the yeast S3 was able to grow at an aggressive pH of order 3 and at a temperature between 20 and 38°C in the presence of a high alcohol content 14%. The production of the S3 cell biomass was improved (Xmax = 4.7308 g/l) by optimizing the temperature, pH, NaCl and ethanol content factors set respectively at 29°C., 4.34, 2% and 3%. 23%. It has been concluded that this strain may well adapt to industrial uses for large scale bioethanol production.