Microbiological monitoring for bioethanol industry is important in order to know the yeast strains that inhabit the fermentation tanks. Currently molecular tools are capable of providing important features for understanding the population dynamics of industrial yeast. The technological bottleneck is in relation to the screening tool of the yeast colonies to be evaluated using molecular biology. This study aimed to evaluate the use of a selective culture medium to make this screening. Although it was possible to obtain different colony profiles when the samples were grown in WLN ((Wallerstein Laboratory Nutrient Agar), it was not possible to obtain a different phenotype for each observed biotype. In only 21% of cases, it was possible to observe a biotype for a phenotype. It is possible to suppose that this occurred because all evaluated yeasts belong to the genus Saccharomyces.