INVESTIGADORES
MALCHIODI Emilio Luis
artículos
Título:
Efficient preservation in silicon oxide matrix of Escherichia coli, producer of recombinant proteins.
Autor/es:
DESIMONE, MF, DE MARZI MC, COPELLO GJ, FERNANDEZ MM, MALCHIODI EL & DIAZ, LE.
Revista:
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 2005 vol. 68 p. 747 - 752
ISSN:
0175-7598
Resumen:
The aim of this work was to study the use of silicon oxide matrices for the immobilization and preservation of recombinant protein producing bacteria. We immobilized Escherichia coli BL21 transformants containing different expression plasmid. One contained DNA coding for a T-cell receptor b chain, which was expressed as inclusion bodies in the cytoplasm. The other two encoded bacterial superantigens Staphylococcal Enterotoxin G and Streptococcal Superantigen, which were expressed as soluble proteins in the periplasm.  The properties of immobilization and storage stability in inorganic matrices prepared from two precursors, silicon dioxide and tetraethoxysilane, were studied.  Immobilized E. coli was stored in sealed tubes at 4 and 20ºC and the number of viable cells and level of recombinant protein production were analyzed weekly.  Different tests showed that immobilized bacteria conserved their E. coli biochemical characteristics intact.  We found that at both temperatures selected, the number of bacteria in silicon dioxide-derived matrix were in the same order of magnitude (109 CFU ml-1) as before immobilization, for 2 months.  After 2 weeks those in an alkoxide-derived matrix decrease to 104 CFU ml-1 at 4ºC and no viable cells were detected at 20ºC.  We found that immobilized bacteria could be used as a starter to produce recombinant proteins with a yield comparable to glycerol stocks, 15 mg l-1 for superantigens and 2 mg l-1 for T-cell receptor b chain.  These results contribute to the development of methods for microbial cells preservation under field conditions.