Abstract
The conditions and modes of flocculation of yeast cells with flocculant produced by Asp. sojae AJ 7002 were investigated. Optimum pH for flocculation was lower than 4.0. Optimum temperature for flocculation was in the range from 30 to 80°C. The addition of saccharides, amino acids, organic acids or EDTA to the reaction mixture had no effect on the aggregation of cells. The addition of salts to the reaction mixture reduced the rate of flocculation. The rate of flocculation was affected by pretreatment of cells with some chemicals and enzymes, such as uranyl nitrate, CTAB, Concanavalin A, pronase and acid phosphatase. Optimum concentration of flocculant for flocculating rate was within the range of 10_??_200 ppm. Age of cells and the addition of cycloheximide and sodium fluoride to the culture media affected the rate of flocculation. These results suggest that the mechanism of yeast flocculation with flocculant is explained in terms of the bridging phenomena between discrete cells and extended polymer chains, forming a three-dimensional matrix that is capable of settling under static conditions.
