Selección de Levaduras Resistentes al Estrés del Proceso Fermentativo y Caracterización de la Fisiología de su Crecimiento

Abstract

The objective of this study was to isolate of whey Kluyveromyces marxianus strains tolerant to stress factors of the fermentation process for ethanol production and obtain biomass for production thereof. Eleven samples of whey, which were supplemented with chloramphenicol to inhibit bacterial growth were analyzed, then dilutions were performed in phosphate buffered saline which were plated on media containing lactose as sole carbon source and phenol red as indicator microorganisms that use it. The lactose positive yeasts were selected. Identification to species was conducted using molecular techniques amplifying the ITS1 (5.8S) ITS2 region. Tolerance tests at high temperatures, low pH and high ethanol concentrations were done. Biomass production was performed in a bioreactor. Sixteen isolates were obtained of whey. Three strains of K. marxianus tolerant to stress factors were identified. The K. marxianus L31 strain was selected for the production of biomass. Future studies should be conducted to determine ethanol production using the selected strain.