The Influence of PH on The Growth of Some Lactobacillus Strains with Different Origins

In this work, influence of pH (the values ranged between 2,0 and 11,5) on growth of nine Lactobacillus strains was been investigated. A significant acid tolerance was observed in all Lactobacillus investigated strains. The values of DO600 registered an increase starting from pH values 3.5 or 4.0. The maximum DO600 values of the most strains were recorded in the pH values ranged between 5.0 and 6.0 except Lactobacillus salivarius strains isolated from the dental root canal that showed the maximum DO600 values at neutral pH. At the Lactobacillus strains isolated from the dental root canal, as for the probiotic Lactobacillus rhamnosus GG strain and Lactobacillus salivarius B and D strains of oral origin a high degree of tolerance of alkaline pH was observed. These strains were able to multiply at pH values ≥ 10,5.