Verificación de una cepa microbiana del sedimento de la Laguna de San Antonio, Cantón Riobamba, Provincia de Chimborazo

Abstract

The verification of the microbial strain of Laguna de San Antonio, Cantón Riobamba, Chimborazo Province was carried out in this investigation, being determined by growth tests in nutrient broths and specific agars if the microbial strain under study (L3) corresponded to the bacterium Xenorhabdus nematophilys, of Gram- characteristic, which was previously studied in other research. The presence of Colony- forming unit (UFC) was evaluated in each means used; the sequencing of the microbial strain was conducted using the polymerase chain reaction (PCR), to finally establish the applicability of the microorganism defined in a bioremediation process. Four samples at random were chosen in the pilot phase from the L3 strain, which were activated by preparing nutrient broth and incubated at 35°C. Subsequently three different types of culture media were prepared for the overcrowding of the activated samples: Nutrient broth 1, Broth X, Broth BHI, and for sowing, three types of agars: Nutrient Agar, MacConkey Agar, and Eosin Agar. Also three sowings of feeding strains were made in the different culture media using the dilution and Pour plate method. The bacterial counting was carried out after the incubation in the boxes which showed a greater growth, and the purification, enlargement and sequencing were performed once completed the process using the PCR of the bacterial strains at Macrogen laboratory in South Korea. Knowing the previous features by documented review of Xenorhabdus nematophilys, and observing the behavior of the bacterium in each medium, which was not cosistent with what was known about it, it was imperative to resort to the analysis of genetic sequencing in PCR to confirm data. The results showed the presence of two types of Gram+ bacteria: Bacillus pumillus and Bacillus altitudinis, different from the species under study, which concludes that the identification of bacterial consortiums can be validated only by this type of procedures and analysis. The applicability of microorganisms found through genetic sequencing: Bacillus pumillus and Bacillus altitudinis are specifically as biological control, fungicides and insecticides, the same that can be applied in bioremediation processe.