Determining contaminating bacteria in the ethyl alcohol production process and their relationship to Saccharomyces cerevisiae flocculation
This work was done in an ethanol production plant, its propose being to study contaminating bacteria in the molasses' dilution, yeast reproduction and fermentation stages by microbiological count, isolation and identifi-cation of predominating bacteria and the relationship between the bacterial contamination and yeast cell flocculation. The effect of a commercial disinfectant such as microbicide in controlling such contaminants was deter-mined. Samples were taken to standardise laboratory methodology for identifying contaminating bacteria in molasses and ethanol producing yeast. The obtained results indicate that the contaminating micro-organisms analysed in the process were Lactobacillus sp. (10 x 105 UFC/ml average) and Zynomonas mobilis (10 x 102 UFC/ml average). It was shown that the presence of contaminating bacteria is directly related to yeast flocculation, pre-senting 106 UFC/ml Lactobacillus sp, 105 UFC/ml Zymomonas mobilis or 103 UFC/ml for a mixture of these two micro-organisms. This phenomenon also depends on many f actor s, such as yeast strain, culture conditions and medium employed. A commercial disinfectant (Sanitech®) was used; this was seen to be very effective for Zymononas mobilis control. The penicillin (Alipen®) contained in one inoculum had a suitable effect on Lactobacillus sp inhibition. It was also shown that a 20 ppm concentration of commercial disinfectant did not affect Saccharomyces cerevisae feasibility, though contamination levels reached 106 UFC/ml populations.
| Principais autores: | , , , |
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| Formato: | Digital revista |
| Idioma: | spa |
| Publicado em: |
Universidad Nacional de Colombia - Sede Bogotá - Instituto de Biotecnología
2002
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| Acesso em linha: | https://revistas.unal.edu.co/index.php/biotecnologia/article/view/30127 |
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