Viabilidad de bacterias ácido lácticas aisladas del suelo del bosque primario Cashca Totoras.

Abstract

The objective of this research was to evaluate the viability of lactic acid bacteria Lactobacillus malefermentans, Lentilactobacillus parakefiri and their mixed culture isolated from the soil of the Cashca Totoras forest in a soluble substrate based on quinoa malt extract. A physicochemical analysis of the malt extract and a plate count were performed to determine the number of viable cells of each bacterium. Three experimental treatments were applied, each with 5 replicates, which were evaluated under a completely randomized design. The results were analyzed by Analysis of Variance (ADEVA) with separation of means by Tukey (p < 0.05). The physicochemical results of the malt extract were a pH of 5.1-5.7, a titratable acidity of 0.14-0.18% and for fermentable sugars values of 1.56 - 2.26 g/L. For viability the results obtained showed highly significant differences (p > 0.01) at 48 hours, at 96 hours significant differences (p > 0.05) and at 24 and 72 hours non-significant differences (p < 0.05). The best treatment is L. malefermentans with values of 3.6x108, 8.7x108, 2.9x109, 3x109 CFU/ml at 24, 48, 72 and 96 hours respectively. In addition, the kinetic parameters such as specific growth rate and biomass yield were 0.05 h-1 and 0.12 g/L. It is concluded that bacterial growth presents a directly proportional relationship between 24 and 72 hours as a function of time since the number of CFU/ml increases with a normal trend. It is recommended to use L. malefermentans as a probiotic in the elaboration of functional beverages since its viable count is higher than 107 CFU/ml.