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

Objective. To evaluate probiotic properties of two native strains of S. cerevisiae. Materialsand methods. Strains were used in assays for tolerance to biliary salts, pH, temperatureand adhesion to Salmonella spp., E. coli and Shigella spp. and antagonism. A 33 x 3 factorialdesign was used, with three levels for each factor (strains, pH and initial concentration ofsubstrate (S0)) by triplicate, to establish the culture conditions for each strain. A commercialstrain (B) was used as control. The selected strain was cultured in a 2L bioreactor; thebiomass 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 differencesbetween the 27 assays (p<0.05) and surface analysis found that the interaction betweenfactors strain and S0 was significant, suggesting for the optimization process the use ofstrain A and increasing concentrations of S0. Results were reproduced in bioreactor with mx0.31h-1, dt 2.18h and Y(x/s) 0.126g/g. the dry biomass obtained was viable and yieldedbetween 6.3 and 6.9% N2/g. Conclusions. Native strains were identified with probioticproperties such as pH, biliary salt and temperature tolerance, and adherence to Salmonellaspp., E .coli and Shigella spp.