IQUIMEFA   05518
INSTITUTO QUIMICA Y METABOLISMO DEL FARMACO
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Analysis of parameters affecting growth and viability of bacteria immobilized in sol-gel silica matrices
Autor/es:
GISELA S. ALVAREZ; MARÍA L. FOGLIA; GUILLERMO J. COPELLO; MARTÍN F. DESIMONE; LUIS E. DIAZ
Lugar:
Villa Carlos Paz, Córdoba, Argentina
Reunión:
Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación en; 2008
Resumen:
The aim of this work was to evaluate the effect of various parameters on bacteria immobilized in sol-gel-derived silica matrices. With this purpose, we evaluated the stress of immobilization over bacteria cultures obtained from different growing states including exponential phase, stationary phase and growing colonies in solid agar. We also studied the effect of cell density during immobilization and the capability of cells to proliferate inside matrices. The effect of complete medium, a carbon and nitrogen source and solely a carbon source incorporation on bacteria viability was studied. In order to induce osmotic stress and the consequent endogenous trehalose synthesis and accumulation, an E. coli culture was exposed to high salt concentration, previous to immobilization. In parallel, some compatible solutes including glycerol, mannitol and trehalose were added during the gelation step. Furthermore, the effect of citric acid as a gelation agent was compared to the use of inorganic acids on bacteria viability preservation over 550 days. Best results to attain longer preservation times were obtained when we immobilized  suspensions with an optimised bacterial number of 1 x 107 cfu/gel in the presence of LB medium using aqueous silica precursors.