Abstract

QUINTERO-RODRIGUEZ, María P.; MONTOYA-ARANGO, Daniela; RESTREPO-POSADA, Deisy C.  and  GONZALEZ-GIL, Diana M.. Conservation of bacteria by freeze-drying in the Microorganisms Collection CM-EM-UDEA, Medellín, Colombia. Biota colombiana [online]. 2023, vol.24, n.2, e1127.  Epub July 01, 2023. ISSN 0124-5376.  https://doi.org/10.21068/2539200x.1127.

Microbial collections preserve strains ex situ with the purpose of maintaining viable, pure and stable microorganisms over time. For this purpose, it is recommended ideally to preserve by cryopreservation and freeze-drying. Currently, the Collection of the Escuela de Microbiología at the Universidad de Antioquia (CM-EM-UDEA) preserves bacteria only by cryopreservation and requires standardization of freeze-drying to maintain the viability of microorganisms for a long time, to optimize storage and to facilitate transport while maintaining their stable characteristics. The aim was to evaluate the freeze-drying process in different bacteria from the CM-EM-UDEA Microorganisms Collection. Six bacteria were selected, the inocula were standardized and different lyoprotectants were evaluated, assessing the freeze-drying efficiency through viability, purity and stability of each microorganism before and after freeze-drying. In most of the microorganisms, the lyoprotectant that presented the best results in viability and physical characteristics of the dry product was sucrose. However, effects observed in the other lyoprotectants in specific microorganisms make them an alternative for use according to their availability. This study enabled standardizing the lyophilization process maintaining 100% purity and viability and stability in high percentages, in most of the microorganisms evaluated.

Keywords : bacteria; conservation; microbial collections; freeze-drying; preservation.

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