ENTRAPMENT OF FLUORESCENT E. COLI CELLS IN ALGINATE GEL

By this experiment we will demonstrate the possibility to obtain genetically modifiedmicrobial strains that can be used as markers in different studies. The traittransferred in this study is the fluorescence in UV light expressed by a gene isolatedfrom jellyfish. This gene was insered into a plasmid carrying ampiciline resistanceand in the operon for arabinose fermentation. The plasmid was called pGLO. E coliHB101 K-12, ampicillin resistant colonies has been obtained. The colonies on theLB/amp/ara plate fluoresce green under UV light and the transformed colonies cangrow on ampicillin. Transformation efficiency = 362 transformed colonies/ μg DNA.The cells where immobilized by entrapment in alginate gel to study the phenomenoninvolved in cells immobilization. After immobilization in alginate gel, 5x104 cells ofE. coli pGLO / capsule and 1,4 x 105 cells of E. coli HB101/capsule has been found.Fluorescent microscopy revealed the presence of pGLO carrying cells into thecapsules. After cultivation of alginate capsules containing E. coli in LB broth, andfluorescent microscopy of the capsule sections, several observations of thephenomenon involved in continuous fermentation using biocatalysts in has beenmade. These cells grow and migrate to the cortical part of the matrix where they areimmobilized.