Screening for Extracellular Acid Protease(s) Production by Wine Yeasts*

Ninety-four Saccharomyces wine yeasts were screened for their ability to produce extracellular acid protease(s) under simulated vinification conditions. Seventeen strains were selected on the basis of their higher proteolytic activity on haemoglobin and casein. These strains showed maximum activity after 20 days of fermentation on haemoglobin and 25 days on casein. Wines obtained from grape juice fermented by the above 17 strains showed significative differences in the residual protein content.