Flocculence of Brewery Yeasts and Their Surface-properties - Chemical-composition, Electrostatic Charge and Hydrophobicity

摘要: The flocculence of a top and bottom fermentation brewery yeast was studied through the cell surface properties: composition (X-ray photoelectron spectroscopy), charge (microelectrophoresis) hydrophobicity (adhesion tests). Aerobic Cultures simulating industrial conditions were performed. The (tendency to flocculate in favourable conditions) has been determined by test which separated occurrence flocculation measurement its manifestation (suspension clearing); flocculating agents ethanol calcium. strain does not with calcium alone but is very sensitive (0.01% (v/v)). lower observed for cells cultured on malt extract as compared accompanied more negative zeta potential. The flocculates only presence enhances process. variation according culture medium harvesting time correlated phosphate concentration. This paralleled potential decrease below value about-35 mV concentration increases. increase function correlates also an hydrophobicity; this obvious cultures than fermentations.