The bacterial microorganisms constitute a good part of the biodiversity of our planet and the importance of its knowledge and preservation has been increased as their multiple utilities in different fields are discovered. The conservation can be done by different methods and one of which offers better results is the freezing; for that reason east project was made whose objective was to evaluate the effects of the freezing in 18 native bacterial species of the collection of cultures of the Program of Bacteriology of the University Colegio Mayor de Cundinamarca, Bogotá- Colombia. The microorganisms including in the study, they were selected considering the variability of metabolic activity between species and their clinical importance, industrialist, biotechnological or environmental. The obtained results were similar in the analyzed species and although some had difficulty to recover their viability and metabolic activity in the first sowing, later they presented displayed one better answer, what allowed to conclude that the phenotypic and genotypic stability does not seem to depend on means of culture nor on the used preservation substance, but of the procedures of freezing and defrost with which the experiment was made. The recommendation of the investigating group is to establish own standardizations and protocols that guarantee the viability and biochemical stability of the microorganisms that are conserved by this method.
