Growth of microorganisms in the pre-fermentation tanks in the production of ethanol
2017
Viera Michalová | Dana Tančinová
<p>Our research was carried out to determine the plate count with a special observation <em>Saccharomyces cerevisiae</em> in the pre-fermenters cereal grains using the classical microscopic method. The cell counts were performed in the Bürker chamber. We followed changes in the plate count, number of <em>Saccharomyces cerevisiae</em> and changes during the yeast propagation in the mash. The mash would present only cultivated yeast <em>Saccharomyces cerevisiae</em> but may occur in a small number of other microorganism's types. Samples were taken during the propagation process in distillery factories. During this period, 30 samples of corn mash were examined. Samples were collected from two tanks during the fifteen generations. The total number of Saccharomyces cerevisiae was reduced and we got a number of unwanted microbiota. The statistical evaluation demonstrated that the growth of unwanted microbiota is directly related to the increase in the propagation of generation in corn mash. The maximum number of yeast cells was found in the twelfth generation 3.052 x 10<sup>8</sup> mL in the propagation tank. The total number of microorganisms in this generation was 3.149 x 10<sup>8</sup> mL and yeasts represent 96.92% of the total microbiota. In the sample B, 95.62% were <em>Saccharomyces cerevisiae</em> during the fifteenth generation. Our results showed that the optimal exchange of the yeast is in 15th generation. Subsequently, repeat the whole process but now with new yeast. These results confirmed our understanding of the relationship between Saccharomyces cerevisiae and contamination during the ethanol fermentation.</p> <!--[endif] -->
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