Abstract Mezcal is the second most important alcoholic beverage produced in Mexico, and the microorganisms present during the fermentation process are primarily responsible for its organoleptic characteristics. Among these, the bacterial populations have been less studied, mainly due to the difficulty of recovering them. The aim was to apply a culture-independent molecular technique to detect the bacterial populations involved in spontaneous mezcal fermentation in Durango State. Samples were obtained from several stages in the mezcal production line. Denaturing gradient gel electrophoresis (DGGE) analysis was performed using DNA extracted from isolated microorganisms and metagenomes obtained from samples directly taken from the fermentation process. This study indicated that non-isolated bacteria were significant in the fermentation process and indicated that the lactic acid and acetic acid bacterial populations present in the monitored process are similar to those present in other regions during fermentation, although they differ in some species that may play essential roles in the development of the typical organoleptic properties of mezcal produced in the State of Durango. Furthermore, this study indicates that culture-independent analysis by DGGE can reveal the bacterial diversity during the mezcal fermentation process without the use of complex isolation procedures and can be a useful tool for the analysis, monitoring and control of mezcal fermentation processes.

Resumen El mezcal es una de las principales bebidas alcohólicas de México, los microorganismos presentes durante la fermentación son los principales responsables de sus características organolépticas, dentro de ellos, las poblaciones bacterianas son las menos estudiadas debido a la dificultad que implica recuperarlas. El objetivo fue aplicar una técnica molecular independiente de cultivo para la detección de poblaciones bacterianas involucradas en el proceso de fermentación espontánea de agave en el Estado de Durango para lo que se obtuvieron muestras de varias etapas en la línea de producción. El análisis por DGGE se realizó a partir de ADN extraído de microorganismos aislados y de muestras tomadas directamente del proceso. Este análisis señaló a bacterias no aisladas como significativas durante la fermentación. Además, sugiere que las poblaciones de bacterias ácido-lácticas y ácido-acéticas son similares a las aisladas en otras regiones productoras de mezcal, pero difieren en algunas que pudieran ser importantes en el desarrollo de características sensoriales típicas del Mezcal de Durango. Además, este estudio indica que el análisis por DGGE puede revelar la diversidad bacteriana durante el proceso sin necesidad de aislamiento y puede ser una herramienta útil para el análisis, monitoreo y control de los procesos de fermentación del Mezcal.

We utilized two-dimensional gel electrophoresis and immunoblotting (2D-immunoblotting) with anti-Sporothrix schenckii antibodies to identify antigenic proteins in cell wall preparations obtained from the mycelial and yeast-like morphologies of the fungus. Results showed that a 70-kDa glycoprotein (Gp70) was the major antigen detected in the cell wall of both morphologies and that a 60-kDa glycoprotein was present only in yeast-like cells. In addition to the Gp70, the wall from filament cells showed four proteins with molecular weights of 48, 55, 66 and 67 kDa, some of which exhibited several isoforms. To our knowledge, this is the first 2D-immunoblotting analysis of the S. schenckii cell wall.