THE EFFECT OF MACROMIXING ON OSCILLATORY BEHAVIOR IN RECOMBINANT FERMENTATION IN A CONTINUOUS STIRRED-TANK REACTOR

A general model is presented for recombinant fermentation in a chemost at in which micromixing may be imperfect. Using the production of tryp tophan synthetase as an example and the dilution rate, D, as the bifur cation parameter, conditions are first derived for Hopf bifurcation in a perfectly mixed chemostat. The bifurcation surfaces in three-dimens ional space are such that oscillatory solutions exist above the surfac es and washout conditions below. A similar analysis is done for imperf ect mixing. The bifurcation region is a concave hyperboloid in the [D, f, n]-space, where f and n are model parameters. It is argued that po or macromixing reduces the range of D over which bifurcation to period ic solutions is possible.