The effect of ethanol on cell wall antigens of Saccharomyces cerevisiae and specific isolation of high ethanol producing strains of this yeast, making use of a serological technique.

Generally, natural isolates of high ethanol producing Saccharomyces cerevisiae obtained by screening are used in alcoholic industries. The methods involved in their isolation and identification are elaborate. Antigenic analysis using antibodies raised against whole Saccharomyces cells indicated species specificity of cell wall surface thermostable antigens. By affinity purification, the specific antibodies could be obtained and used for specific isolation of S. cerevisiae. Antigenic studies using antibodies raised against isolated cell walls of fermentatively grown S. cerevisiae indicated the occurrence of thermolabile antigens common to Saccharomyces species. Higher concentrations of these antigens could be detected in those S. cerevisiae that had the ability for high ethanol production. The concentrations of these cell wall common antigens increased with increasing culture age and ethanol accumulation in culture broths. In younger yeast cells, the concentration could be increased by growing the cells in a medium containing added ethanol. Using dilutions of cross absorbed antibody specific for common antigens and Ouchterlony test, high ethanol producing S. cerevisiae could be identified.