Effect of cell surface hydrophobicity, charge, and zymolectin density on the flocculation of Saccharomyces cerevisiae

Cell surface investigations for the yeast strains LCC1209 (Flo1 phenotype), LCC125 (NewFlo phenotype), and LCC1240, a nonflocculent variant of LCC1209, are reported. The strains were examined for their degree of flocculation, surface hydrophobicity, and surface charge. Cell surface zymolectin density was quantitated with a fluorescent avidin-fluorescein isothiocyanate probe as well as a radio-labeled tritiated-mannose probe. Additionally, fluorescence microscopy was employed to examine the cell wails of the two flocculent yeast strains. The strains showed different hydrophobicity, surface charges, and apparent zymolectin densities. Cell surface hydrophobicity correlated with flocculation significantly (r = 0.684, P < 0.001). It was found that 82 and 75% of the variations in flocculation (n = 48) can be explained by the level of zymolectin density and zymolectin affinity for the Flo1 and NewFlo strains, respectively.