Identificación preliminar in vitro de propiedades probióticas en cepas de S. cerevisiae

Objective: To evaluate probiotic properties of two native strains of S. cerevisiae. Materials and methods: Strains were used in assays for tolerance to biliary salts, pH, temperature and adhesion to Salmonella spp., E. coli and Shigella spp. and antagonism. A³3 × 3 factorial design was used, with three levels for each factor (strains, pH and initial concentration of substrate (S₀)) by triplicate, to establish the culture conditions for each strain. A commercial strain (B) was used as control. The selected strain was cultured in a 2L bioreactor; the biomass was dryed by temperature and the resulting product was assayed to determine N₂ concentration and cellular viability. Results. Strain A (from sugar cane), tolerated pH 3 ± 0.2, 0.3% (w/v) of biliary salts and 42°C. The factorial ANOVA found significant differences between the 27 assays (p<0.05) and surface analysis found that the interaction between factors strain and S 0 was significant, suggesting for the optimization process the use of strain A and increasing concentrations of S₀. Results: were reproduced in bioreactor with m_x 0.31h^-1, dt 2.18h and Y_(x/s) 0.126g/g. the dry biomass obtained was viable and yielded between 6.3 and 6.9% N₂/g. Conclusions: Native strains were identified with probiotic properties such as pH, biliary salt and temperature tolerance, and adherence to Salmonella spp., E.coli and Shigella spp.