Physiological properties and plasma membrane composition of Saccharomyces cerevisiae grown in sequential batch culture and in the presence of surfactants

The effects of various polyoxyalkylene glycols (PAG) of different molecular mass, colza oil and oleic acid were studied on Saccharomyces cerevisiae grown without aeration in sequential batch culture on beet molasses wort. It was observed that PAG improve cell growth, viability and alcohol production with the best efficiency when their molecular mass was between 2000 and 3300 Da. Plasma membrane analysis revealed the presence of a higher percentage of ergosterol but a low percentage of lanosterol in cells showing the best viability. Colza oil had no significant action while oleic acid had a positive effect similar to that of the most efficient surfactant tested in this study. The kinetics of sphaeroplast production revealed that recycled cells were more resistant to lytic enzymes and that culture of the cells in the presence of the surfactants had no effect on cell wall lysis.