Evaluation of culture conditions of Lactobacillus acidophilus y Lactobacillus casei on laboratory scale, with inulin as carbon source

Abstract

Lactobacillus acidophilus and Lactobacillus casei are lactic acid bacteria that function as probiotics, are generally used for the formulation of functional foods and grow at similar culture conditions. Bacteria metabolize specific sugars such as inulin, this substance is a fructooligosaccharide whose prebiotic function contributes to the proliferation of intestinal microflora and prevents the colonization of pathogenic microorganisms. In this study, the concentration of inulin both molecular grade and reagent grade, were evaluated together with the pH of the medium for growth of both Lactobacillus species. The aim was to obtain a medium containing a unique value of pH and an ideal percent of inulin for the growth of bacteria. An optimal medium for the growth of L. casei was recovered, supplemented with 4.31% of inulin reagent grade and pH 7.465. For L. acidophilus no medium resulted as optimal for the bacteria and their growth occurs in extreme values of each variable. It suggests that pH range and extreme conditions of bacteria impedes to obtain an optimal growth medium. In conclusion inulin is an able sugar for the probiotics biomass production.