[Cultivation integrated with acetate acid filtration on Escherichia coli]

A fed-batch fermentation integrated with filtration process was proceeded in a synthetic medium with the use of a hollow-fibre membrane filter. The activity of alpha A interferon reached 1.4 x 10(9) u/L, which was increased 320% over that of a control process. The integrated process was then proceeded in the synthetic medium supplemented with yeast extract during the earlier stage. The addition of yeast extract not only reduced the accumulation of acetate, but also promoted the production of alpha A interferon. The maximum activity achieved 1.9 x 10(9) u/L during the fermentation, which was increased 480% over that of a normal process.