Improvement of lactic cell production.

The production of Lactobacillus brevis has been improved by changing the medium composition and the physiological conditions. The cellular concentration reaches 8.2 x 10(10) cells/mL in 21 h with a fed-batch technique in MRS medium. Freeze-drying has been used as technology for drying the cells and survival rates have been improved with different additives such as glycerol, CaCO3, and skimmed-milk powder up to 70%. A model has been developed to predict the stability of freeze-dried cultures during long-term conservation. This model, based on Arrhenius equation, has been confirmed by experimental data.