EFFECT OF CULTURE PH ON THE GROWTH-CHARACTERISTICS AND POLYSACCHARIDEPRODUCTION BY LACTOBACILLUS-CASEI

The effect of initial pH on the growth characteristics and exopolysacc haride (EPS) production by Lactobacillus casei was studied. After a fe rmentation for 24 h, the cell growth in APTg broth was related to the metabolism of glucose to lactate in the pH range tested (4.0 - 6.0), w hile a ''partial uncoupling'' between growth and lactate formation was observed in milk cultures. When lengthening the incubation time up to 72 h, the results obtained were strongly influenced by the initial pH . A pH range of 6.0-6.5 was found to be the optimal one for the EPS pr oduction both in milk and in APT g broth after a fermentation for 24 h .