THE STUDY OF THE EFFECT OF FERMENTATION TEMPERATURE ON THE GROWTH KINETICS OF SACCHAROMYCES CEREVISIAE YEAST STRAIN, IN THE PRESENCE OR ABSENCE OF SUPPORT, BY CHROMATOGRAPHIC TECHNIQUES

The Gravitational field-flow fractionation (GFFF) in combination with the conventional gas chromatography and high-performance liquid chromatography were applied in order to study the effect of temperature (15 degrees, 20 degrees, 25 degrees, and 30 degrees C) on the fermentation kinetics and the proliferation of the alcohol-resistant and psychrophilic Saccharomyces cerevisiae (AXAZ-1) yeast strain, in the presence or absence of wheat starch granules as immobilization carrier. The results indicated that both systems (free and immobilized cells) performed better at 30 degrees C, whereas at lower temperatures decreases in the fermentation rate and in the number of viable cells were observed. The duration and the rate of the fermentation process were shorter in the case of immobilized cells as compared with free cells, which is in accordance with literature. Moreover, wheat starch granules proved to be capable and efficient for the immobilization process as it is a cheap material, of food grate purity, available in large amounts. The activation energy for the fermentation process (Ea) was reduced in the case of immobilized cells as compared with free cells.