USE OF COMPARATIVE REASONING TOOLS FOR EVALUATION OF THE EFFECT OF STERILIZATION CONDITIONS ON FERMENTATIONS TO PRODUCE ACIDIC FIBROBLAST GROWTH-FACTOR

The effects of various medium sterilization conditions on fermentation s of a recombinant, acidic fibroblast growth factor (aFGF) producing E scherichia coli have been studied. Changes in the medium resulting fro m sterilization were monitored by pH and absorption spectra. This simp le experiment provided excellent data for the demonstration of the use fulness of comparative reasoning tools in order to evaluate the effect of sterilization on fermentation performance. The time profiles of th e main parameters (e.g., carbon dioxide evolution rate, dissolved oxyg en, pH, and aFGF productivity) were simplified into piecewise contiguo us linear segments, each of which was sequentially numbered. The lengt h, position, and slope of each line were then characterized. Applicati on of the comparative reasoning tools confirmed that separate steriliz ation of the glucose was necessary for the success of the process, des pite adding to the cost and complexity. The comparative data analysis also showed that scaleup with longer sterilization holding and cooling times would not be detrimental to aFGF production. (C) 1995 John Wile y & Sons, Inc.