ELECTROPHYSICAL MONITORING OF CULTURE PROCESS OF RECOMBINANT ESCHERICHIA-COLI STRAINS

A novel method for monitoring the cell culture process has been develo ped. The method is based on the measurements of electro-optical charac teristics of cell suspension, calculation of cell structure parameters , and the relationship between accumulation of proteins and change of these parameters' employment. Application of the meth od for the monit oring of a culture process of a recombinant strain is considered. The process of growth of recombinant strains cannot be sufficiently predic ted and the direct measurement of cell culture parameters is unlikely to be the most efficient way of solving the problem. Escherichia coli plasmid-free and recombinant strains synthesizing the fusion protein c onsisting of tumor necrosis factor-alpha (TNF) and thymosin-alpha(1) ( T) were studied. It was found that cytoplasmic electroconductivity of the strains investigated increased during the culture process. The acc umulation of insoluble recombinant pThy-315-encoded hybrid protein TNF -T in cells resulted in a decrease of the membrane dielectric permeabi lity. To determine variations of membrane dielectric permeability the amount of insoluble recombinant protein TNF-T in the bacterial cells s hould be calculated. (C) 1996 John Wiley & Sons, Inc.