Recombinant E. coli strains, producing minimal core and full-sized streptavidin variants were obtained. E. coli BL21 Codon Plus (DE3) RIPL as host cells and pET19b plasmid carrying gene of minimally-sized core (miniSAV) or full-sized (SAV) streptavidin were used. The synthesis of miniSAV results in its “packing“ as insoluble inclusion bodies. Protein was solved in buffered solution with 6 M urea and purified by ion exchange chromatography in denaturating conditions. Denatured miniSAV yield was 130 mg per liter of E. coli culture. The renaturation gives only 10-12% of the functionally active protein. Full-sized streptavidin localizes in cytoplasm in soluble state, but its toxicity causes low yield of the protein. It was found that the protein induction at the end of logarithmic stage of the cells’ growth increases the yield approximately 2 times. After affine chromatography on 2-iminobiotin agarose column SAV was obtained practically in individual state. The yield of functionally active protein was 29-30 mg of per culture liter. One molecule of full-sized streptavidin bound 3.9 biotin molecules as was shown by colorimetric analyses using HABA (4-hydroxyazobenzene-2-carboxylic acid). E. coli BL21 Codon Plus (DE3) RIPL/pET19bSAV strain was stable during storage with 20% glycerol at -70°С, that was shown by repeated two-years reseeding. Both streptavidin variants form tetrameric structure spontaneously and “work” as a bridge between biotinylated molecules in solid-phase microanalysis.