A method has been developed for immobilizing viable but nongrowing Escherichia coil in highly uniform patches. The patches consist of a thin layer of bacteria in acrylate vinyl acetate covered with a thin layer of the same polymer devoid of bacteria and sealed by the edges. This method permits study of immobilized cell physiology in biocatalytic films by the assay methods used for suspended cells. Large numbers of patches of immobilized E. coli can be generated on metal or polyester sheets. Those described here are 12.7 mm in diameter; in them the cell layer is 30 μm thick and contains more than 5 x 108 viable cells. The method allows the cell-plus-polymer layer and the polymer sealant to be varied in thickness from 5 to 60 μm and from 7 to 80 μm, respectively. No leakage of cells was detected from 87% of the patches during 15 days of rehydration. Culturability of the immobilized cells, released by shaking the cells out of the porous polymer layer, was 80% of pre coating culturability. E. coli β-galactosidase activity and measurements of total RNA and DNA from immobilized and suspended cells indicated that cells immobilized in the thin polymer layer have higher specific β-galactosidase activity and a slower total RNA degradation rate than suspended cells over 15 days.
|Original language||English (US)|
|Number of pages||12|
|Journal||Biotechnology and bioengineering|
|State||Published - Jan 5 1999|
- Biocatalytic films
- Immobilized viable cells
- Latex patch coating of E. coli