IQUIBICEN   23947
INSTITUTO DE QUIMICA BIOLOGICA DE LA FACULTAD DE CIENCIAS EXACTAS Y NATURALES
Unidad Ejecutora - UE
artículos
Título:
Metabolism of Klebsiella pneumoniae freeze-dried cultures for the design of BOD bioassays
Autor/es:
BONETTO, M. C.; SACCO, N.; ASTRID HILDING OHLSSON; CORTÓN, EDUARDO
Revista:
LETTERS IN APPLIED MICROBIOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2012 vol. 55 p. 370 - 375
ISSN:
0266-8254
Resumen:
Aims: The survival rate of freeze-dried cultures is not enough information for technological applications of microorganisms. There could be serious metabolic/structural damage in the survivors, leading to a delay time that can jeopardize the design of a rapid metabolic-based bioassay. Therefore, we will compare metabolic activity (as ferricyanide reduction activity) to survival (as colony-forming units) for different freeze-drying procedures and biochemical oxygen demand (BOD) calibrating solutions, in order to find optimal solutions for K. pneumoniae bacteria. Method and Results: Here we tried several simple freeze-drying processes to obtain a Klebsiella pneumoniae freeze-dried culture capable to be used in a rapid metabolic-based bioassay. Electrochemical measurements of ferrocyanide and logarithmic/arithmetical survival rates obtained with the different freeze-dried cultures were used to choose the best freeze-drying process that leads to a rapid metabolic-based bioassay. Conclusions: The use of milk plus monosodium glutamate was the best choice to obtain a K. pneumoniae freeze-dried culture with metabolic stable conditions after 35 days of storage at -20°C without the need of vacuum storage and ready to use after 20 min of rehydration. We also show that viability and metabolic activity are not always directly correlated. Significance and Impact of the Study: This study shows that particular combinations of cryoprotectant and pretreatment of K. pneumoniae cells originated certain freeze-dried cultures successfully applied for the design of a rapid BOD bioassay.