MIXED CULTURE-GROWTH KINETICS OF STREPTOCOCCUS-THERMOPHILUS AND LACTOBACILLUS-BULGARICUS

A simple microbiological technique was used to differentially enumerate growth of Streptococcus thermophilus and Lactobacillus bulgaricus in a mixed culture. The growth of the microorganisms in the mixed culture was satisfactorily simulated with a set of modified logistic equations. This simple model was valid for various initial biomass concentrations and their ratios. It did not need substrate or product data for simulation of biomass growth, which may simplify the calculations in fermenter design. It was shown that our model may also be regarded as a special case of a common mixed culture model: Volterra's competition analysis. © 1990.