Validation of kit for rapid method for of viable yeasts quantification during fermentative process

• Grant number: 15/22699-1
• Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE
• Start date: November 01, 2016
• End date: June 30, 2018
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Science
• Principal Investigator: Pilar Rodriguez de Massaguer
• Grantee: Pilar Rodriguez de Massaguer
• Company: LABTERMO Consultoria Microbiológica Ltda
• City: Campinas
• Associated researchers: Alessandra Regina da Silva

Abstract

The performance and activity of yeast is critical in the ethanol production industry. For this reason, fast and accurate methods, which analyze the viability of yeast during fermentation are essential elements in this process. Thus, this research will aim: to validate the use of solutions made by LABTERMO with reagents purchased in the local market, used in fluorimetric reading the viability of yeast solutions in laboratory scale and on an industrial scale. In both steps, the yeast used is Saccharomyces cerevisiae. At predetermined time intervals, aliquots are withdrawn during the fermentation process and counts made by four different methods: A. hemacytometer count using staining with methylene blue; B. standard plate count - using specific methods for mold count and yeast; C. determining the number of active cells measured by fluorimetry using the Easy Count method with imported kit and D. determining the number of active cells using fluorometric readings kit made by LABTERMO. In laboratory scale fermentation is conducted in 300mL erlenmeyer flask with 150 mL of sterile wort pH and Brix standardized vegetative cells inoculated with the yeast suspension 5mL, reaching a final concentration of ~ 106UFC / ml. The fermentation is conducted at 32 ° C and samples collected every 30 minutes for 7h. In the industrial scale, samples will be collected during a typical cycle of fermentation and the viability monitored until the end of fermentation. Each sample collected will be subjected to viable cell count by four methods described above. The counts by traditional methods (staining with methylene blue and plate count) are conducted in duplicate and by two different analysts. In scores performed by the method Easy Count (imported kit or formulated national), for each sample, each analyst will do 10 repetitions at each collection interval. Errors and standard deviations of the results of each reading, among analysts and each method will be analyzed statistically. This will be a way to validate the proposed method with the kits made by LABTERMO versus the method that uses the Easy Count kit imported. For this validation, the method with less error and standard deviation between operators will be established as the best performance. Through the results can be validated using the Easy Count, with kits made by LABTERMO for later marketing, at a much reduced price. The demand for this type of method is large in the alcoholic fermentation industries, therefore, the faster the observed drop in viability more quickly the problem can be fixed. (AU)