Correlation between surface potential and flocculation of Saccharomyces cerevisiae

Two liquid fermentating yeasts and two solid fermentating yeasts were prepared for the research to study the relevance between surface potential and flocculation of Saccharomyces cerevisiae. Saccharomyces cerevisiae FFC144 and L2 Y were inoculated from generation to generation,zeta potentials of different breed yeasts and different generation were measured using a standard instrument,yeast flocculability was measured by the method of calculating cells sedimentation rate. Results showed that,when ionic strength was 0,zeta potential of solid fermentating yeasts were less than 30 m V(absolute value),while the liquid fermentating yeasts in all cases were more than 30 m V,the flocculation rate of the solid fermentating yeasts which were cultivated72 h reached 80.2%,and the liquid fermentating yeasts possessed a maximum value of only 14.4%. There was no significant alteration of the zeta potential in the process of fermentation,and so was the Saccharomyces cerevisiae FFC2144 in the process of subculturing. Flocculability of the Saccharomyces cerevisiae FFC2144 was enhanced gradually which reached 94.8% in the 20 th generation. Different Saccharomyces cerevisiae possessed different zeta potential,the magnitude of which objectively reflected the strength of flocculability. In the process of yeast aging,flocculation had nothing to do with the surface potential of cells.