Implementación del método de conservación para bacterias ácido lácticas aisladas del suelo de bosques primarios de la parroquia Baños

Abstract

Using microorganisms is significant in agriculture, food, and human and animal health. Therefore, the preservation of strains is required, and this is not easy because it must ensure the survival of lactic acid bacteria for a considerable period, ensuring the viability, purity, and genetic stability of the bacteria. Therefore, the research's main objective was to implement a conservation method for lactic acid bacteria from primary forests of the parish of Baños. The methodology implemented in the research began with the reconstitution of the microorganisms previously isolated in solid and liquid media. The microbiological load was adjusted by nephelometry. For the application of the preservation method, 30% glycerol was used; these were placed at -20°C, four °C, and 16°C for a period of 90 days. The viability of the bacteria was evaluated by microbiological counting, morphological and biochemical tests, carbohydrate fermentation tests, acidification, and mobility to verify if the bacteria underwent changes or mutations. The results obtained from the preservation in lactic acid bacteria at -20°C in 90 days for the L. rapi strain remained in values of 6.9×105 Colony Forming Units (CFU/g) and 5.56.9×105 CFU/g implying that there was no loss in the microbiological concentration; the L. agilis strain presented values between 6.16.9×106 CFU/g and 1.96.9×105 CFU/g, with a partial loss. It is concluded that none of the strains showed morphological and biochemical changes, as well as carbohydrate fermentation, mobility, and acidification tests during the 90-day storage period. It was considered that this method is appropriate for the long-term preservation of lactic acid bacteria with agroindustrial potential.