Characterization of palm wine yeasts using osmotic, ethanol tolerance and the isozyme polymorphism of alcohol dehydrogenase

Physiologic characteristics of ten palm-wine yeast isolates obtained from nine localities in four provinces in southern Cameroon were assessed using sensitivity to chloramphenicol, tolerance to acetic acid, ethanol tolerance, osmotolerance as well as protein and alcohol dehydrogenase (ADH) polymorphism. None of these isolates was sensitive to 30 mu g/ml chloramphenicol and all were non-tolerant to 1% acetic acid. Some of the isolates (Vip 2 and Vip 10) showed tolerance to both high sucrose and ethanol concentrations, criteria which are useful in fermentation. Results indicated that 80% of the strains were able to grow at 15% alcohol solution and only 20% grew on 40% sucrose solution. The denatured protein pattern (SDS-PAGE) as well as the native protein pattern was similar for all strains. The ADH pattern showed a high diversity based on which isolates were differentiated into three patterns. The electrophoretic patterns showed that the ADH pattern was the best criterion for diversity characterisation because of its specificity and variability.