Mutagénesis, selección y caracterización nutricional de una cepa nativa de Saccharomyces cerevisiae para la producción de isobutanol
In this study, a collection of yeast strains of Saccharomyces cerevisiae was evaluated in order to select a strain with an increased isobutanol production during the fermentation process. The strain 209-2-8 presented the higher isobutanol production, which was 301.7 mg/L, when a diluted sugar cane s...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión aceptada para publicación |
| Fecha de publicación: | 2019 |
| País: | Colombia |
| Institución: | Universidad Nacional de Colombia |
| Repositorio: | Repositorio UN |
| Idioma: | español |
| OAI Identifier: | oai:repositorio.unal.edu.co:unal/75846 |
| Acceso en línea: | https://repositorio.unal.edu.co/handle/unal/75846 |
| Access Level: | acceso abierto |
| Palabra clave: | Ingeniería y operaciones afines Química y ciencias afines isobutanol Saccharomyces cerevisiae strain improvement ethanol fermentation sugar cane mejoramiento de cepas etanol fermentación caña de azúcar |
| Sumario: | In this study, a collection of yeast strains of Saccharomyces cerevisiae was evaluated in order to select a strain with an increased isobutanol production during the fermentation process. The strain 209-2-8 presented the higher isobutanol production, which was 301.7 mg/L, when a diluted sugar cane syrup supplemented with ammonium dihydrogen phosphate was used as substrate. Further, this yeast was subjected to a mutagenesis process with N-methyl N-nitro nitrosoguanidine, followed by a selection procedure with sulfometuron methyl. As a result, the S. cerevisiae strain Q1 was obtained, which presented an isobutanol production 1.92 fold higher than the parental strain, with a final concentration of isobutanol of 580.8 mg/L. Also, the production of isoamyl alcohol by the Q1 mutant strain was 1.3 fold higher than the parental strain. Subsequently, Q1 mutant strain was subjected to a mutagenesis process with ethyl methane sulphonate followed of an enrichment procedure with nystatin in order to obtain an L-leucine auxotrophic mutant (called Q1m). The strain Q1m reached an isobutanol production of 811.0 mg/L, when a diluted sugar cane syrup supplemented with ammonium dihydrogen phosphate and L-leucine was used as a substrate. This strain also produced a lower isoamyl alcohol level than the parental strain. Through a preliminary bioreactor assay, it was determined that the productivity was 16.4 mg/Lh. On the other hand, a Plackett-Burman experimental design was performed, by using as a reference a chemical defined media. Results showed that potassium dihydrogen phosphate, biotin and pH levels were the main factors that affects isobutanol production. |
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