Microbiota de levaduras asociada a la superficie de las uvas de la Región del Comahue, Argentina

LOPES C; ZAJONSKOVSKY I; RODRÍGUEZ ME; SANGORRÍN M; LAVALLE L; CABALLERO A; VAN BROOCK MR

San Miguel de Tucuman

Jornada; XVI Jornadas Científicas, Sociedad de Biología de Tucumán; 1999

Grapes have long been considered the primary source of wine yeast in spontaneous fermentations. Several factors, as climatological conditions, age and phytosanitary treatments of the vineyard, grape variety, etc, affect the yeast microbiota of grapes. The aim of this study was to analyze the yeast microbiota related to Trousseau and Malbeck type grapes from the same vineyard. The grapes were gathered by random sampling. The indigenous yeasts were obtained by agitation followed by sonication (sound grapes) or centrifugation (crushed grapes). Isolation of yeasts were carried out on agar YEPD and agar L-lys, at 25°C. The isolates were identified according to Kreger van Rij (1984). Lack of significant differences between counts on the two culture media were observed. C. pulcherrima and K. apiculata were the major yeast species identified in both type grapes, but their proportions were different. Other common species were A. pullulans, R. rubra, and T. pullulans but C. guillermondii, C. stellata, D. hansenii, Cr. albidus while Cr. macerans were only associated to Malbeck type grapes. From 120 isolates analyzed none was identified as S. cerevisiae. These results show a significative incidence of grape variety on yeasts microbiota. they are also an additional evidence on the numerical inconsistency of S. cerevisiae cells in nature.