AN ONLINE PHYSIOLOGICAL-STATE RECOGNITION SYSTEM FOR THE LYSINE FERMENTATION PROCESS-BASED ON A METABOLIC REACTION MODEL

A metabolic reaction model was developed for the lysine fermentation p rocess by Corynebacterium glutamicum AJ-3462 to estimate the physiolog ical state of the cells-that is, the growth and production activity, a nd the flux distribution of metabolites-from on-line measurable rates only. First, the extended Kalman filter was applied to eliminate noise in the measured rates. Then, using the metabolic reaction model, the lysine production rate and flux distribution were calculated. The esti mation results allowed the physiological state of lysine production to be recognized, and an appropriate measure corresponding to the estima ted state, such as intermittent addition of glucose and/or leucine, to be taken to maintain a high level of lysine productivity in batch cul ture. Finally, application of the recognition system enabled lysine to be produced from glucose at a higher yield than that from glucose- or leucine-limited exponential fed-batch cultures. (C) 1997 John Wiley & Sons, Inc.