Use of McFarland Standards and Spectrophotometry for Yarrowia Lipolytica QU69 cell counting

New researches on microorganisms capable of synthesizing different carbon sources have been made to fulfill the growing use of biotechnology to obtain products with economic value and the search for reducing the environmental impact caused by inadequate waste disposal. The yeast Yarrowia lipolytica has stood out for its ability to grow in hydrophobic environments and has been used in bioconversion processes to produce various industrial products of interest. McFarland standards and Neubauer chamber are the two most common methodologies employed to count viable cells, but they were originally made to count bacterial cells and blood cells, furthermore, those methodologies can be quite subjective. In order to optimize yeast cell count for use in bioprocesses, McFarland standard associated with spectrophotometry was used to estimate the amount of strain Yarrowia lipolytica QU69 cells present in a suspension. It proved to be a reliable, accurate and reproducible method, and it could be applied in routine analysis and classroom experiments.