Unstructured model for the decline phase of batch cultures of Lactobacillus helveticus growing on supplemented whey permeate

An unstructured model was previously developed to describe growth of Lactobacillus helveticus; this model accounted for the biomass kinetics until the stationary state was achieved. In the new model, the decline phase was modelled as an exponential decay, all the parameters having an obvious biological meaning. By means of both expressions, the whole growth history is described. This model has been tested for a wide range of yeast extract (YE) supplementations (5-30 g l(-1)), i.e. for various autolysis kinetics (from 8 to 26% of autolysis after 8 h of death phase); in all cases, the new model fitted accurately the experimental data. (C) 2002 Elsevier Science B.V. All rights reserved.