PROBIEN   20416
INSTITUTO DE INVESTIGACION Y DESARROLLO EN INGENIERIA DE PROCESOS, BIOTECNOLOGIA Y ENERGIAS ALTERNATIVAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Yeast biota associated with traditional fermented beverages in Patagonia
Autor/es:
LOPES C.A.; SANGORRÍN M.P.; SÁEZ J.S.; CABALLERO A.C.
Lugar:
Villa Carlos Paz, Córdoba, Argentina
Reunión:
Congreso; VI Congreso Nacional Sociedad Argentina de Microbiología General; 2009
Resumen:
Several raw sources, including cereals and fruits has Wild fruits such as strawberries(<i>Fragaria chiloensis</i>), “maqui” (<i>Aristotelia chilensis</i>), “calafate”(<i>Berberis</i> spp.), apples (<i>Malus</i> sp.), as well as seeds of different plantshave been traditionally used by aboriginal communities in Patagonia to preparedifferent fermented beverages. A particularly interesting fermented beverage is thatobtained from seeds of the <i>Pehuen</i> tree (<i>Araucaria araucana</i>), fromwhich the Mapuche´s communities prepared the fermented beverage called<i>Mudai</i>. No works involving the microbial biota present during <i>Mudai</i> andother traditional fermented beverages in Patagonia have been published until now.With the aim of investigate this particular yeast biota for the first time, juices obtainedfrom <i>Pehuen</i> seeds and wild apples obtained in the traditional way werefermented in sterile flasks under laboratory conditions (3 fermentations from<i>Pehuen</i> seeds and 2 fermentations from apple). Yeast sampling in completemedium was carried out during the processes, evidencing maximum populationdensities of 1.5x10<sup>8</sup>cfu mL-1. Molecular identification of these coloniesby using ITS1-5.8S-ITS2 PCR-RFLP and sequence analyses, revealed the presence ofonly two yeast species at the beginning of <i>Mudai</i> fermentation:<i>Hanseniaspora uvarum</i> and <i>Saccharomyces cerevisiae</i> in percentagesof 80% and 20% of the total biomass respectively. In Apple fermentations, non-<i>Saccharomyces</i> yeasts corresponded to 25% and 84% of the total isolates atthe begining of the two analyzed fermentations respectively, including isolatesbelonging to <i>H. uvarum</i> and <i>Metschnikowia pulcherrima</i>. In subsequentstages of all <i>Mudai</i> and apple fermentations, the yeast biota correspondedexclusively to <i>S. cerevisiae</i> in all analyzed fermentations.Intraspecific analysis of the <i>S. cerevisiae</i> isolates from <i>Mudai</i>fermentations by means of mtDNA-RFLP analysis evidenced a single restrictionpattern. This kind of biological homogeneity is frequently observed in inoculatedfermentations in which the yeast starter selected culture dominate the fermentationprocess, but it is not expected in natural processes Traditional production of thisbeverage does not involve the use of commercial yeasts; however, the environment inwhich this product is elaborated is in permanent contact with commercial yeasts usedin bread making. MtDNA-RFLP analysis of commercial bakery yeasts showed thesame molecular pattern detected in <i>Mudai</i> fermentations, evidencing a crosscontaminationof yeasts in these traditional fermented products. The intraspecificdiversity in <i>S. cerevisiae</i> populations from apple fermentation samples are beingcurrently analyzed in order to find indigenous <i>Saccharomyces</i> isolates and toevaluate its phylogenetic relationships with regards to wine strains of this species.