Control biológico de hongos micotoxigénicos con bacterias ácido lácticas
The lost food caused by the contamination with microorganisms is an important problem to solve human survival. The contamination by fungus is a topic of great interest. because the fungus biosynthesized mycotoxins associated with several diseases. In this sense to give solutions to the problem menti...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2022 |
| País: | México |
| Institución: | Universidad Autónoma Metropolitana |
| Repositorio: | Repositorio Institucional de la UAM Iztapalapa |
| Idioma: | español |
| OAI Identifier: | oai:bindani.izt.uam.mx:js956g12g |
| Acceso en línea: | https://doi.org/10.24275/uami.js956g12g |
| Access Level: | acceso abierto |
| Palabra clave: | info:eu-repo/classification/LEM/Lactic acid bacteria info:eu-repo/classification/LEM/Bacterias lácticas info:eu-repo/classification/LEM/Agentes antifunginos info:eu-repo/classification/cti/6 |
| Sumario: | The lost food caused by the contamination with microorganisms is an important problem to solve human survival. The contamination by fungus is a topic of great interest. because the fungus biosynthesized mycotoxins associated with several diseases. In this sense to give solutions to the problem mentioned before, in this thesis, the use of lactic acid bacteria as antagonists of the growth of Aspergillus carbonarius is proposed. The work focuses on enhancing the antifungal effect of LAB modifying the formulation of the culture medium and identifying metabolites with antifungal activity. Firstly, an analysis of the fermentation products of the LAB was carried out. The strains were characterized as homofermentative, because mainly produced lactic acid, and a low concentration of propionic acid, ethanol, and LAB strain 31 (MZ809351) also produced butyric acid. On the other hand, it was found that the highest antifungal activity occurred when the cell-free supernatant was obtained between 72 and 96 h of LAB culture under anaerobic conditions. Secondly, we analyzed the effect of the concentration of the nitrogen source and some nutritional factors. LAB strains 7 from Mexico and 31 from the Ivory Coast exhibited the highest antifungal activity, moreover, it was found that both yeast extract and ammonium citrate can be eliminated from the culture medium without affecting both growth and antifungal activity. Lastly, this part shows the antifungal activity was reduced when calcium chloride was added to culture media and was not affected by the presence of sodium chloride. The last stage corresponds to the analysis of the results of adding polyols to the MRS culture medium on the production of metabolites with antifungal activity. The highest growth inhibition of A. carbonarius was obtained by cultivating L. plantarum MZ809351 (LAB 31) in the presence of xylitol and glycerol. Under these conditions, in addition to 9-octadecenoic acid, 3 diketopiperazines or cyclic dipeptides were identified, including cyclo (Leu-Leu), cyclo (Pro-Gly) and cyclo (Val-Phe), these compounds have been related to microbial antifungal activity. On the other hand, adding xylitol and glycerol to the MRS broth reduced the Ochratoxin A (OTA) content to 56.8 and 54.7%, respectively. This study shows the potential for using L. plantarum as a biocontrol agent. |
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