SEPARATION OF RECOMBINANT ESCHERICHIA-COLI FROM CULTURE BROTHS BY ADSORPTION TO MODIFIED CARRIERS AND CONTROLLED-RELEASE OF AN EXPRESSED PROTEIN

Investigations were carried out concerning the considerate and selecti ve separation of intact, product including recombinant E. coli cells f rom culture broths by adsorption. Adsorbents were synthesized on basis of porous glass ''SIRAN'' (Schott, Mainz) by chemical surface modific ation in order to adapt surface charge density and hydrophobicity to t he surface behavior of the hosts. It is possible to accumulate up to 5 8 mg dry biomass per gram carrier by using the fixed bed circulation t echnique and by simultaneous dosage of small amounts of polycationic r eagent Polyethyleneimine (PEI). The method is especially useful for th e separation of shear stress sensible microorganisms. Preferred releas e of the recombinant product staphylokinase (SAK) from the cytoplasmat ic space of the adsorbed cells was done by permeabilization of the cel ls and elution of the column with suitable agents. Thus, product enric hment was achieved simultaneously with the clearence of host cell prot eins and other cell components or fragments.