Production of interferon alpha A by Escherichia coli W3110 (pEC901).

The maximum specific growth rate, saturation constant, maintenance coefficient and growth yield for E. coli W3110 (pEC901) and the host, W3110, were estimated through continuous cultivation of the two strains. The growth rate of the transformant was lower than that of the host, while its maintenance metabolism increased due to the existence of plasmids pEC901. Both the plasmid stability and the expression level of interferon increased with the increase in dilution rate. In fed-batch culture, the growth rate of W3110 (pEC901) was maintained at a high level by controlling the feeding rate of glucose, and the interferon titer reached 2.5 x 10(10) u/l, which was greatly improved compared with those reached in shaker flask cultures.