MODELLING OF LACTIC ACID PRODUCTION BY STREPTOCOCCUS CREMORIS HP

Abstract

A mechanistic mathematical model is developed for Streptococcus cremoris HP which uses the intracellular substrate concentration as a state variable for the fermentation system. The concept of a threshold intracellular substrate concentration and a new model of product inhibition are introduced to account for a pronounced lag phase and a strong metabolic product inhibitory effect. Parameters for the model are determined from experimental data from seven batch runs with widely varying initial and final conditions. Statistical tests and comparisons with another model are carried out. A possible method of optimisation is discussed in terms of the developed model.